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From the makers of Civilization... comes a game about civilization's last stand.

"Two possibilities exist: Either we are alone in the Universe or we are not. Both are equally terrifying."
Arthur C. Clarke, opening quote for Enemy Unknown

"Those who play with the devil's toys will be brought by degrees to wield his sword."
R. Buckminster Fuller, opening quote for Enemy Within

XCOM: Enemy Unknown is a remake of X-COM (note the lack of hyphen) developed by Firaxis Games and published by 2K. It was released on PC / Xbox 360 / Playstation 3 on October 9 2012, Mac OS X on April 25 2013, iOS on June 20 2013, Linux in June 2014, and PlayStation Vita on March 22 2016.

In the year 2015, Earth comes under attack by alien forces. In response, a secretive Council of Nations activates the XCOM project, a Multinational Team tasked with fighting the alien invaders and researching their technology to protect humanity. The player takes the role of the Commander of XCOM, and with the help of various NPC advisors, guides XCOM to victory (or defeat) by managing the whole organization, including base building, research, manufacturing and sending fighters to intercept UFOs. The main focus of the game, however, is on the ground combat, where the player takes control of a small squad of soldiers and fights turn-based battles against the aliens.

In combat, the player commands up to six soldiers who can level up and specialize in four different classes (Assault, Support, Heavy, and Sniper) with unique weapons, equipment, and abilities. Each soldier gets two actions per turn, though using any action other than 'move' normally ends that unit's turn. Every soldier is equipped with one primary weapon, one pistol (Heavies get a Rocket Launcher instead), and an additional piece of equipment that the player decides (such as a grenade or medikit).

Outside of combat, the player manages the XCOM base, where you're forced to choose which upgrade projects to research, what weapons/items to build, what new facilities to build, and which alien threats to go after with your limited resources. Players also have to monitor the panic in various countries; if it gets too high, the country might withdraw their funding from the XCOM project (and if too many leave, it's an automatic Game Over).

For Downloadable Content there's two:

  1. Slingshot, was released in December 2012. It added additional soldier customization options, a series of inter-connected Council missions in China with a unique soldier, and earlier access to certain technologies/upgrades.
  2. Second Wave, was released in January 2013 for free. It added 16 previously Dummied Out difficulty modifiers, including options that make the game more like the original X-COM, or even more extreme.

An expansion, XCOM: Enemy Within, was released in November 2013. It added new enemy types, maps, items and customization options, the ability to genetically enhance XCOM troopers, a new XCOM unit called the Mechanized Exoskeletal Cybersuit Trooper and a new alien resource called Meld. It also introduces a new enemy faction: EXALT, a human paramilitary group acquiring alien technology to Take Over the World. Unlike the aliens, EXALT resorts to cloak and dagger tactics, such as increasing panic and stealing XCOM's resources, forcing the player to use intel gathering and counter intelligence ops to bring them down. Finally, it added a second mission chain like Slingshot, and indeed it had originally been designed as one.

The XCOM: Long War Game Mod adds significantly more content to the game. It was first released in 2013.

A Sequel, XCOM 2, was released on February 5, 2016.

A character page is under construction here. Please add all character- and class-specific tropes there!


Prepare for deployment, Trope One:

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  • Action Girl: Lots and lots of them from every corner of the globe. Enemy Within introduces a unique female unit in Annette Durand.
  • Adam Smith Hates Your Guts: In Enemy Within, the prices of constructing plasma weapons have been jacked up to encourage capturing them from the aliens. This doesn't apply to interceptor armaments, meaning a regular plasma rifle now costs about four times the price of a heavy ship-borne plasma cannon. Then again, the plasma rifle research notes do say that reducing the weapon's size so a human could comfortably hold it was troublesome in the project.
  • Adaptational Badass: The aliens' designs have been revamped and made generally more menacing.
    • Floaters. They had absolutely horrible AI combined with the worst marksmanship of the aliens in the original game, as bad as some of your rookie troopers. Now, they can drop out from the sky right behind your squad's flank from almost anywhere on the map, use their unlimited flight time to their advantage to pin down your soldiers and lastly, have a significant facelift so they look like fearsome aliens with jetpacks and not a weird guy trying to look like Superman.
    • Mutons are still green and purple, but they don't look like humans in muscle suits anymore. The are much wider-framed, appear to be wearing rebreathers, and have considerably more obvious armor.
    • Chryssalids will still ruin your entire day if you aren't careful, just like in the original, but they're horrible blade-legged quadrupeds instead of people in lobster suits.
    • Sectopods were already threatening-looking in UFO Defense, but that's kicked up a notch. Now their thundering footsteps are booming sounds, they constantly release steam or highly pressurized air even after destruction, and their motto is 'Stuff Blowing Up'.
  • Aggressive Play Incentive: After Enemy Unknown was criticized for rewarding overly cautious play, the Enemy Within expansion added a new resource, Meld, that comes in containers that self-destruct if not recovered within a certain amount of turns. It's extremely useful, but whether it's worth the risk to the soldiers is up to the player to decide.
  • Alien Abduction: The invaders will abduct civilians from countries not under satellite surveillance, often striking multiple cities on different continents at the same time. Successfully stopping them will gain XCOM additional support from the country they save, but panic will rise in the countries they couldn't respond to, and if the countries are on different continents, the whole continents that XCOM didn't assist will take a hit to panic. Having full satellite coverage neutralizes all abductions.
  • Alien Autopsy: An important part of figuring out each alien type's capabilities, as well as unlocking new Foundry projects and items for Engineering to manufacture. In Enemy Within, it also unlocks new genetic augmentations. The MEC Trooper's "Vital-Point Targeting" passive ability also does 2 extra damage to any alien that has been autopsied.
  • Alien Invasion: The point of the game. Mostly an all-out attack, with some infiltration by Thin Men and psionic aliens. Though it turns out the aliens are holding back in an attempt to test humanity rather than wipe it out.
  • Aliens Steal Cattle: Some raids on Abductor-class alien ships will have quite a few slaughtered cattle scattered around the storage pods.
  • Aliens Are Bastards: The aliens, as you'd expect from an X-Com game. They're cruel and violent and launch an all-out war against humanity without explanation, with abductions, terrorism and Human Resources all on the table.
  • All Your Base Are Belong to Us: The aliens eventually attack the XCOM HQ in Enemy Within, due to the aliens overclocking their mind control powers (and the living psionic amplifier that is Annette Durand) to manipulate the XCOM staff inside to breach the defenses. It's up to you to Hold the Line against their onslaught.
  • Alternate Continuity: Separate canon from the classic games.
  • Always Accurate Attack: Melee attacks have no chance to miss at all. That's really bad if a Chryssalid or Berserker is near an injured soldier, but at the same time excellent when your Stormtrooper-inaccurate MEC Trooper with a Kinetic Strike Module is right in the face of an injured Ethereal mind-controlling your best Assault.
  • Always Close: When your soldiers arrive at a bomb disposal mission site, you've got 4 turns to either disarm the bomb or lengthen the countdown by disabling its energy sources. To get to the mission site, it's entirely possible that your soldiers just boarded a jet in Europe and flew to Australia.
  • Always on Duty: Heavily implied for your soldiers. They're always available to go at a moment's notice when it's time to scramble the Skyranger for a mission, unless they're in the infirmary, being genetic modified, on a covert op or undergoing PSI testing. You can send the same squad on mission after mission, sometimes hours apart, without your soldiers getting time off. Taken to its logical conclusion, they live at the base, never take leave, and don't even go into town for a night out since the potential consequences for not being available when needed, which could happen at any given time, include the loss of Earth to the aliens.
  • Ambiguous Robots:
    • When Dr. Vahlen autopsies the Cyberdisk, she notes that while it appears to be a machine, its internals are arranged in a manner similar to organs in a living creature and it possesses what amounts to a circulatory system with plasma instead of blood. She states in her notes that she is unsure if it is a robot or a silicon-based cybernetic life form.
    • The Outsiders are referred to as "energy constructs" and "organic technology", but what they are exactly is anyone's guess. Unlike the rest of the aliens, their presence is never explained; they're also the only aliens who don't make an appearance in the Temple Ship mission.
  • Amazon Brigade: There's an achievement for completing a mission with an all-female team.
  • Ancient Conspiracy: EXALT is an ancient conspiracy stretching back centuries which seeks to use subversive, underhanded methods to Take Over the World. The alien invasion gives them the chance they need.
  • And the Rest: Care must be taken to not rely too much one one squad. If you have a squad of Colonels that all get injured by a Sectopod's cluster bombs, they're going to be laid up in the infirmary for days, maybe weeks. And if that Abduction Alarm goes off, and you only have rookies on your bench (especially late in the game), you're in for a very bad day.
  • Anti-Frustration Features:
    • Normally on Ironman, you cannot restart a mission if you lose, but are forced to continue the game with the casualties and/or panic gain you've gotten. However, you can restart both the first (if the tutorial isn't activated) and last missions if you fail them. The first is so you can start over without having to set up an entirely new game, the second is because the Volunteer is one of a kind and activating the Ethereal device stops all progression. Enemy Within also allows the XCOM Base Defense mission to be restarted on both regular and Ironman runs.
    • Unit equipment doesn't vanish if they perish. This means that even if you lose most of your team wearing end game armor and using expensive plasma weapons, you can equip their replacements with the same loadout. This helps mitigate some of the end game losses by allowing your rookies to at least have a fighting chance in late game encounters should you lose your best and brightest, and hopefully level up from the experience. Of course, there exists a Second Wave option, "Total Loss", that disable this mercy should you want more difficulty.
    • AI priorities in Terror missions might be intentionally set up to alleviate potentially frustrating scenarios. There are times when you'll be in a really bad position relative to an enemy, yet the enemy will often choose to kill a civilian even if they could realistically benefit more by killing a soldier. A Chryssalid can be surrounded by three juicy soldiers ready to shoot it the next turn but still opt to run off and kill a nearby civilian instead. As a result, it can be a lot easier to kill the Chryssalid and zombie in subsequent turns than it would be to lose a soldier and try to do the same with reduced firepower and some potentially panicked soldiers. If the implanted corpse is nearby, you can even use a grenade to damage the Chryssalid while also killing the zombie before it gains its full strength.
    • If enemy advancement outstrips your tech, it is possible to start facing Elite Mutons and Heavy Floaters while still using laser weapons and carapace armor. If this happens, you will likely get TPK after TPK. If you have full satellite coverage you can't get a game-over this way, because you won't have any panic penaltiesnote . So you're stuck in and endless loop of sending underequipped rookies against the toughest enemies in the game, and they can't level up because they keep getting wiped out, and you can't build them better equipment because you need resources you can only get from completing missions. This is especially a problem in Ironman mode, where you can't abuse Save Scumming to complete tough missions. The saving grace is that every so often you'll shoot down a Small Scout with only a few aliens or get a Council Mission with only Thin Mennote , so you can, little by little, collect enough resources to build better equipmentnote .
    • If you go a few turns in a mission without any of your troopers seeing any aliens, someone will hear a sound coming from the direction of a group of remaining aliens regardless of distance so you'll know roughly where you should be looking.
    • A psionic is needed to beat the game. The highest chance of a soldier being one is 31%note  Normally it more 25%, thus it is possible to keep having soldiers fail the test again and again. Thankfully the developers put a rule in to force the sixth trooper you test to be psionic as long as you have no psionic, including if all your other psionic died.
  • Anyone Can Die: Nobody in your ground teams is truly safe from death. A single lucky plasma bolt can send your favorite and greatest soldier to an early grave, and if you're playing on Ironman, those soldiers are gone permanently.
    • Played with in Enemy Within. The Secondary Heart gene modification ensures that your soldiers will always be critically wounded instead of dying when they lose all of their HP; however, anybody who doesn't have it is out of luck, even moreso now that the officer training that gives a chance (based on their rank) for your soldiers to be able to do so by default has been removed.
  • Apocalypse How: The Temple Ship's self destruct would cause a Planetary/Physical Annihilation level event. However the Volunteer pulls a Heroic Sacrifice to get it away from Earth in time.
  • Apocalyptic Log: The News Ticker, moreso if things are going badly.
  • Applied Phlebotinum: Meld, in Enemy Within, is an alien substance made of techno-organic nanomachines that can combine different organic components, or interface organic physiology with machines. It can be used by XCOM to genetically modify soldiers to enhance their abilities, or to convert them into cybernetic MEC troopers.
  • Arbitrary Headcount Limit: Your squad is limited to 4 members, which can be expanded to 6 with some upgrades, even though you can clearly see your skyranger has room for more. You can also have only one squad answering alerts at once, even if you have enough soldiers to field additional squads. It seems XCOM can't afford a second Skyranger.note  In addition, XCOM can only have a maximum of 99 soldiers recruited, though that's almost a non-issuenote .
    • Enemy Within ups the ante by including an achievement for finishing the game without EVER increasing the squad limit. It also decreases the max number of recruitable soldiers to 75.
    • The limit is upped to 7 members in Enemy Within, but only during Covert Ops missions where you can send a full squad to extract the single unit infiltrating EXALT. Furthermore, your operative on the Covert Operation has only a pistol and no armor, making them more of a liability than an asset, especially since you fail the mission if they die.
    • Upped in the XCOM Base Defense mission. In addition to 4 to 6 of your best soldiers (depending on your squad size limit), you get around 6 base security personnel, essentially Rookies with conventional weapons and Frag Grenades. Your squad can also be reinforced at three points in the mission if your headcount of soldiers + security is lower than 8.
  • Arm Cannon: Plasma Pistols as used by the Sectoids. They get converted to a more conventional layout if you manage to capture one intact and have already researched enough plasma technology to know how to modify it safely.
  • Armor Is Useless: Played With to hell and back.
    • The standard armor your soldiers start out with adds a whopping 1 health, but better armor adds more hitpoints, can potentially increase their defense rating to equal that provided by low cover even while standing in the open, and tend to have other special abilitiesnote .
    • For the aliens, it's a zig-zag game. Their heavily-armored regular Mutonsnote  will always have less health than the physically frail Sectoid Commandersnote . However, the even heavier-armored Muton Elitesnote  will outdo the Commanders. Then the Ethereals, who are dressed in robes and have bodies so atrophied they can only move thanks to their psionics, has the exact same health as a heavily armored Berserkernote , which can take more hits than the Elites. Finally, the Sectopods, which are effectively walking tanks, have the largest health pool of any aliennote . The Sectopods also get an upgrade in Enemy Within: their armor, in addition to giving them monstrous health, also reduces all damage by 50%, effectively doubling their health to 60.
    • Enemy Within again zig-zags back and forth. MEC Troopers, which are Cyborg torsos inside armored mechanical chassis, have some of the highest health pools in the game. However, genetically modified soldiers only have a sleeveless vest with combat leggings, and putting on better armor only changes the breastplate and boots while giving them the same bonuses as the full set worn by a regular soldier. Additional shoulder pads and leggings are only cosmetic options.note 
    • Basic EXALT units tend to be about as or more durable than their XCOM equivalents while wearing only a nice suit, sometimes with a Kevlar vest over it. On the other hand, their Elites wear better body armor and have higher health as a result.
  • Artificial Brilliance:
    • The invaders' tactical sense is remarkably complex. They make very good use of the flanking mechanic - most of a player's introduction to flanking will be by having the technique used against them (on higher difficulties). They'll also throw grenades when they can't get a decent shot, will use Overwatch themselves if they know you're there, attempt tactical retreats, and most funny of all, accidentally use up their movement turns blundering into the middle of your units leaving them without cover and ripe for the slaughter. Basically they act like players, occasional missteps and allnote .
    • Sectoids deep in cover tend to Mind Merge those in front of them, and will stay hunkered down. They'll also scurry away behind their compatriots if they're not already there.
    • Thin Men in particular are very intelligent, and will actively seek rooftops and proper sniping positions from which to support other aliens, particularly when supporting "heavy" troops like Mutons. They will also use their gas-spit attack to deny you the use of good sniper spots, but only if you are already in position.
    • The invaders will also "panic" (not the in-game debuff kind) if you trounce a squad with overwhelming force. Removing all but one of the invader units in the same turn that you discover them frequently sends the survivor fleeing from your soldiers for their lives. Of course, this becomes less likely as the strength of the invader unit goes up, or if they lack the intelligence to do so (Berserkers and Chyrssalids).
    • The civilians in Terror missions are miles better than the ones in the old games. They will run away from the aliens, up to and including diving through windows and shimmying up drainpipes to get away, at least after the first turn.
    • Berserkers have the ability to break down some types of cover, causing damage to any XCOM soldiers near it in the process. Berserkers tend to specifically target XCOM soldiers behind breakable barriers when possible, in order to expose them to fire from the other aliens.
    • Seekers cloak and specifically wait until they can hit an XCOM soldier who is isolated from the rest of the squad. They also often wait until you're fighting other enemies before striking.
    • Aliens mind controlling troops will often have them run towards your own soldiers and then use explosives to damage their pawn along with their target. Either it forces you to kill the mind controlled soldier, or it weakens them for when the mind control wears off, a win-win scenario.
    • EXALT troops use all of your favorite tactics: Grenades to destroy cover, smoke to protect their allies, splitting up and flanking, using rooftops to position their snipers... at least until they run wide in the open to reach an objective like the encoder in Data Retrieval missions.
    • Alien behavior on terror missions fits their described characteristics / personalities. Enemies like Chryssalids or zombies are mindless and aggressive, and will gleefully attack anything they can get their claws on. Floaters are semi-intelligent but also in a constant state of berserker rage, and are just as likely to fire on civilians as they are XCOM operatives. Lastly, enemies like mutons and thin men are highly intelligent and disciplined, and will typically ignore civilians in favor of firing at your squad - they know who the far greater threat is.
    • If your soldiers can No-Sell an enemy's ability, they won't even bother using it. For example, if the whole squad is completely immune to strangulation (having a Respirator Implant or Chitin Plating, toting Bioelectric Skin or wearing Titan/Archangel/Ghost Armor), Seekers won't even try to strangle them – they'll fly behind the soldiers in a good flanking position, stay airborne up high, and shoot. Thin Men will save their poison for non-immune targets in their sight range (anyone carrying a Medikit or Respirator Implant, or wearing Titan/Archangel/Ghost Armor, is 100% poison-immune), and will just shoot the most exposed target.
  • Artificial Stupidity:
    • The pathfinding AI can be odd at times. Sometimes your troops will go up a level and then drop down to get to a piece of cover that they could have just walked straight to.note  Blithely running directly through clouds of poison without any poison immunity rather than going around them is also common.
    • Sectopods sometimes attempt Rocket Barrages while indoors, which ends exactly how you'd think firing rockets with an obvious obstruction in the way would. They also have weapons that deal splash damage (prior to Enemy Within), which they'll still use on adjacent targets which results in them possibly killing themselves.
    • Floaters will sometimes use their "Launch" ability to rocket directly into a position out of cover and in the middle of your squad, thereby ending their turn and painting a huge target on themselves.
    • Mutons (all three types) tend to love to run right into Overwatch traps. If you see a Muton, chances are it isn't alone. Overwatch everyone, and watch his buddies waltz right into your barrage of fire. At least on Classic Difficulty.
    • Seekers seem to be spotty on their AI, sometimes choosing not to engage any of your soldiers even when they're under fire from their own allies, or suddenly attacking when the immediate area is clear of enemies and your whole team is on Overwatch (specifically waiting for a Seeker attack).
    • In Terror! missions, aliens will sometimes ignore wounded soldiers and target harmless civilians, allowing the same soldier who would have been dead otherwise to shoot them dead the next turn.note 
    • For whatever reason, aliens always skip their turn when under suppression or seeing soldiers on Overwatch, at least if they don't have an easy shot. This happens even if they're being flanked at the moment (and the possible death from reaction fire is preferable to the certain death next turn), or if they're hiding behind a car THAT IS ON FIRE. Fixed as of Enemy Within, for the most part.
    • AI troops have a tendency to, on occasion, move to a position to outflank one of your soldiers or hit someone standing in the open... and then use up their remaining action to move somewhere else instead of shooting, despite having a great shot. This tends to be pretty rare though, so don't count on it happening as a matter of strategy.
    • EXALT members are fond of using Zerg Rush, even if the numbers aren't on their side. Apparently, capturing the encoder is what enables their intelligence, because if someone's not on it, their operatives will expend both of their actions to get into the area and ignore your soldiers while doing so. Since getting into cover is apparently optional, they'll often get roasted the next turn. As a result, they usually won't give half a damn about going Overwatch if they're in a good defensive position or if the vehicle they're hiding behind bursts into flames.
    • It's worth noting that in Normal and Easy mode, the enemy AI is limitednote , which causes a number of seeming stupid actions. On Classic and Impossible, the AI in "unbound"note , greatly increasing the capabilities of the aliens and making mistakes on their part much less likely.
  • Artistic License – Biology: The research in xenobiology kicks off after the team is able to sequence and analyse the alien specimens' genome. This is given a nod, as the personnel remarks how lucky they were to be able to sequence it using their existing methods. Naturally, this is pure fiction. All existing genetic sequencing methods rely on exploiting quirks of the unique chemistry of the ACTG-based DNA strands and their natural polymerisation mechanisms (such as during cell division), often by using a pool of "labelled" nucleobases that make it visible if the genetic strand at any given position is an A, C, T or G, or by using methods that cause a premature end of polymerisation if a specific nucleobase is integrated. Needless to say, it would be extremely unlikely for alien genetic material to be literally identical on a chemical level with ours. Even more, if sequencing did work, actually annotating the genome, i.e. matching genes to actual function, is a process that takes years of research and experimentation even for normal Earth organisms. Similarly, there is no way the team would be able to conclusively say that any given feature in an alien body is the result of genetic modification as opposed to being a different species, or having undergone physiological treatment or simply lifestyle. Earth biology is so diverse in the variety of forms it can produce from the same template even within the same species that there's no way anyone could make a blanket statement on something alien being genetically engineered with that little data.
    • Furthermore, the 'Genetics Lab' and everything associated with it. The idea that the aliens would use genetically modified troops is not far-fetched. However, using genetic modification to change the physical abilities of existing, adult soldiers completely ignores what DNA is actually for in the body. That kind of technology (which is to say, selectively modifying the genetic content of only specific adult somatic cells, such as for gene therapy) is still decades away from us in the real world, if it's possible at all.
  • Artistic License – Chemistry: It is stated in the report of the Ethereal autopsy that the science team used carbon dating to place the Ethereals at several thousand years of age. However, accurate carbon dating would be next to impossible without knowing the current and past concentration of carbon on the Ethereals' home-world, not to mention living organisms are intrinsically harder to date due to carbon going into them continually.
  • Artistic License – Military: When your troops are reloading their weapons, they will occasionally exclaim "Rack, tap, bang". The correct phrase - tap, rack, bang - is the procedure for what to do in the event of a firearm malfunction (tap the bottom of the magazine hard, rack the action and resume shooting), and although technically correct, it's not used to describe a reload procedure.
  • Asskicking Leads to Leadership: As your soldiers do well, they get new abilities and get promoted up through the ranks. Anyone who has reached Colonel is a true badass.
  • Ass Kicking Pose: The aliens will usually strike one upon discovery. Especially the Thin Men, who make poses that would turn James Bond green with envy.
  • A Taste of Power: Used in the demo, where in the second mission, all your squad members have a couple of promotions each and several pieces of equipment like Medikits, unlike in the full game, which has a squad of Rookies with 1 Heavy and just frag grenades. They face Floaters and Thin Men during the mission too, not just Sectoids.
  • A-Team Firing:
    • A missed shot will go high and wide typically – especially amusing at point-blank range. However, because the game selects a random trajectory originating from a gun's barrel (which doesn't preclude the shot actually firing straight), coupled with the random nature of the miss animations, this trope can also subvert itself as a shot visually hits a target but has no effect. Became the norm come Enemy Within.
    • Rockets are particularly bad about this, because even though they allegedly only have a 10% miss rate, when they do miss they can miss spectacularly, potentially hitting friendly soldiers or not even hitting one enemy despite a huge blast radius. It can be less about veering and more about firing in completely different direction, possibly hitting walls that should be completely blocked off by other walls.
  • Attack Drone: On both sides of the fray.
    • The aliens' Drones are multipurpose flyers that can repair mechanical units or fire a relatively weak energy pulse, and can also self-destruct. The Cyberdiscs are apparently half-mechanical, half-organic combat units. The Sectopod is a huge bipedal automated weapons platform, packing mortars and beam weapons galore. Enemy Within adds the Seekers, their only unit which has an Invisibility Cloak, who favor going after isolated soldiers and strangling them. The Drones can also be hacked with the Arc Thrower (after relevant research) and used to repair your Attack Drones, but only for the duration of the mission at hand; unfortunately, you can't take a functional drone back.
    • You get your own in the form of the S.H.I.V. (Super Heavy Infantry Vehicle), with a whole tech tree dedicated to them. They function exactly like the tanks of yore, including, in the Alloy S.H.I.V.'s case, functioning as mobile cover. There are three varietiesnote  that can either have a small Gatling gun, a short multibarreled laser cannon, or a plasma cannon. With the proper upgrades, they can suppress enemies, repair themselves, and take reaction shots at anything that gets within a certain distance. Soldiers with an Arc Thrower can repair them.
  • Attack Reflector: Ethereals can reflect your attacks with their mental powers, though the reflected attack only does 2 damage regardless of what was fired at the Ethereal.
  • Awesome, but Impractical: A lot of the abilities your troopers receive as they gain promotions involve choices between this and Boring, but Practical.
    • Alloy S.H.I.V.s and potentially MEC Troopers can be used as partial and full-cover, respectively, but the usefulness of this function is mainly against weaker aliens. Due to the prevalence of grenade-happy enemies in the late game, who will always use one if two or more soldiers clump together, having a soldier take cover behind their S.H.I.V. or MEC compatriot practically waves a "Throw Grenade Here" sign at the aliens.
    • PSI Panic. For some reason, the target almost always shoots at your soldiers when it panics (it almost never shoots at its allies or retreats, unlike your own panicked soldiers), so it's usually easier to kill it outright.
    • Snipers have choose between Squadsight and Snap Shot early on. Squadsight lets them fire their sniper rifles at any alien any member of your squad can see, provided the sniper's line-of-effect to that alien isn't blocked. Snap Shot lets them fire their sniper rifles after moving, but at a significant -20 Penalty to Aim. And sniper rifles gain an Aim Penalty for being within less than 10 tiles of the target. Further throwing the benefit into Squadsight's favor, are the Sergeant rank options of Gunslinger and Damn Good Ground. Gunslinger gives +2 damage with Pistols. Combined with all the foundry projects, they will do damage comparable to the same tier Assault Rifle in the hands of a sniper, and with good accuracy, making the purpose of Snap Shot almost pointless. Damn Good ground, gives a +10 bonus to Aim and Defense, which combines with the default +20 Aim for having the high ground on an enemy. Combined with Archangel armor, Snipers in open environments can just fly up and rain death down upon any alien that pops their head outside of a building, while remaining almost completely safe at the mission's drop zone.
      • Enemy Within however, changes this up to push the issue into making both options look tempting. Squadsight is nerfed to be unable to score critical hits with such aided shots without the use of the Sniper's Headshot ability being activated. Snap Shot in the meantime, was buffed by reducing the Aim penalty to only -10. The addition of the new Seeker alien unit, means leaving your sniper in the back without any means of preventing strangulation, is very risky until appropriate items, melds, or armor is developed.
      • Later, they have to choose between Double Tap and In The Zone. Double Tap lets you shoot twice, every time, if your first action was to shoot. In The Zone lets you shoot as many times in one turn as you like, provided every shot kills a flanked or out-of-cover alien. In The Zone could wipe a whole map of aliens in a single turn, but this requires a fair amount of setup and least a little luck to pull off.
    • Assault abilities tend to come in two flavors: Increase damage or increase suvivability. You can give them abilities that let them shoot twice in a single action, increase damage and critical chance the closer they are to enemies or with more enemies visible, or give them increased HP from heavier armors and decrease the enemies chance to hit the more of them are around. Basically a choice between mitigating the risk of their high-risk, high-reward playstyle, or increasing the reward.
  • Badass Boast: Soldiers and special characters have many badass lines when activating their abilities and taking actions.
  • Badass Crew: A team of experienced soldiers turn into this, mowing down the aliens with ease.
  • Badass in a Nice Suit: Thin Men (especially in higher difficulties) can mess you up to kingdom come in early game. All while wearing their fine navy blue suits. The EXALT operatives also wear business suits, because they're civilians in day jobs who take up terrorism on the weekend.
  • Badass Normal: Regular soldiers without any fancy psionics, cybernetics and/or bio-augmentations, once they gain enough experience. All they have are their skills, guns, and armor.
  • Bad Luck Mitigation Mechanic: On normal or lower difficulties, the game applies a +10% hit chance for each missed shot by a soldier until they hit. The reverse is applied to alien shots, applying a -10% chance for a hit for each successful hit until they miss.
  • Barrier-Busting Blow:
    • Berserkers are fond of pulling this. If there is a full-sized wall between them and an XCOM soldier, they will charge through the wall and deal an insane amount of damage. Unless the soldier is wearing endgame armor, you'd better make a spot on the Memorial Wall.
    • MECs armed with the Kinetic Strike Module can do this as well, and much better than Berserkers, hitting for a whopping 12 points of damage (or 18, with upgrades; enough to instakill a Muton Elite). Even better, it's one of the first modules you can get on a basic MEC suit; nothing that you come across can take that much damage until you get to Cyberdiscs and Berserkers (the Mechtoid can take it, but only just, and they're pretty rare in the early game).
  • Bathos: No matter the situation, the fedora from Enemy Within looks out of place. Put it on a MEC Trooper for extra hilarity.
  • Battleship Raid: Whenever you attack a downed Battleship-class UFO. They're so large that there is nothing else on the Battlescape; the Skyranger lands on the Battleship itself. The Slingshot Downloadable Content adds a raid on a disoriented Battleship still in flight.
  • Beam Spam:
    • You get the option for this with with the Scatter Laser, Heavy Lasers and SHIVs and Interceptors/Firestorms equipped with Laser Cannons. The aircraft version of the Laser Cannon has as its trump card the ability to hit harder than Avalanche missiles at a very high fire rate, essential for tougher UFOs that can shake off an engagement faster.
    • Plasma weapons typically fire few high-power shots, but there are two exceptions: Outsiders firing their Light Plasma Rifles shoot in long six-shot bursts, and Heavies with Heavy Plasma LMGs fire in fast eight-round bursts.
  • Beat Them at Their Own Game:
    • Mind-controlling aliens are a nasty surprise, able to turn the tide of battle against the player in one turn. However, you can start producing your own psionics, and with a high-Will psi-soldier with Psi Armor and Mind Shield, you can start reliably mind-controlling those same aliens in return. There's even an achievement* for doing this to an Ethereal, the strongest alien psionic.
    • One of the achievements* in Enemy Within has the player invoke this, requiring you to kill a Berserker with a MEC Trooper's Kinetic Strike Module.
    • Another achievement* requires you to kill an EXALT Elite Sniper with one of your own snipers.
  • Beef Gate: The game throws several of these at you to ensure you're not resting on your Research laurels.
    • You should have Laser weapons by the first Terror Mission so you can reliably two-shot Chryssalids, Carapace Armor by the Mutons to resist their firepower, and so on. A few of these thresholds can be extended with sound tacticsnote , but Berserks and Cyberdiscs with Drones are a hard wall to hit for a strike team with only basic equipment.
    • Woe is you if you build the Hyperwave Relay without at least one Firestorm in your Hangar. This makes the Overseer craft appear regularly, and it eats up the regular Interceptors like candy with its dual-weapon defense system and extremely fast speed. You have to get busy building Firestorms, STAT. Meanwhile, as you build it (or wait for missions to even get the parts to build it with, the Overseer keeps appearing on radar, and you have no choice but to ignore it. This makes panic rise and your monthly rating go down the toilet, and there's nothing you can do about it.
  • Benevolent Conspiracy:
    • The Council Of Nations, in spite of their nature as the Omniscient Council of Vagueness, is entirely well-intentioned. They fund and support XCOM in their efforts to protect Earth and save its citizenry from the Alien invasion, and there's no evidence that they're up to any shenanigans on the side.
    • It is hinted that the aliens themselves, or at least the Ethereals, may see themselves as good conspirators. They seek to push humanity to the next level, so that they may attain psychic ability to prepare them for "what lies ahead", whatever that means.
    • Averted with EXALT. There is nothing benevolent about their conspiracy, they're only in it for their own gains.
  • The Berserker:
    • Mutons have Blood Call, and ability that boosts other Mutons, and makes them act more aggressively with their movements and fire.
    • The aptly-named Berserker, an extremely durable breed of Muton that has the ability to charge through walls to get to your soldiers. They also get a small free-action move towards any soldier that hits it. Fortunately, they charge blindly rather than stick to cover. A clever commander can exploit this, forcing them to trigger Overwatches and step into your other soldiers' line of sight.
  • Better to Die than Be Killed: Members of EXALT in Enemy Within cannot be captured for interrogation like most aliens can. If you shock them with the Arc Thrower, they'll stab themselves with a syringe full of poison before they lose consciousness, so they don't risk revealing information damaging to their operations. Doing this the first time nets you an achievement, "Pain In The Neck".
  • BFG: The MEC troopers in Enemy Within use their superhuman strength to carry comically enormous guns. The basic MEC weapon is a giant minigun wielded much like a rifle; as your technology advances, you can equip your MEC troopers with a railgun and, finally, a plasma-tech particle cannon that vaporizes in one shot anything smaller than a Mechtoid or Cyberdisc.
  • Big Bad: In contrast to the original game, where the aliens were led by an "Alien Brain", the Ethereals, led by the Uber-Ethereal, are very much the bad guys here. They're the guiding intelligence behind the invasion and the various alien species are the other species that they conquered first, in an attempt to find/create a species that is both physically strong and psionically gifted. It's never made clear what what they need this for, but they do mention that it's in preparation for "what lies ahead".
    Uber-Ethereal: "Behold the greatest Failure... of the Ethereal ones. We who failed to ascend as they thought we would. We who were cast out. We who were doomed to feed on the Gift of lesser beings... as we sought to uplift them... to prepare them... for what lies ahead."
  • The Big Board: A pair of them.
    • The Hologlobe (a giant holographic globe) sits in the middle of the Mission Control in the XCOM headquarters. All missions available are shown on this, along with tracking the movements of UFOs, Interceptors, and the Skyranger. XCOM has a second Hologlobe in the Delta Sectionm as seen in the Base Defense.
    • The raid on EXALT HQ in Enemy Within shows that EXALT has a Hologlobe of their own... the only difference being that it's red. When the mission is completed, this Hologlobe shorts and fizzles out, symbolizing the end of EXALT.
    • The other is the world map in the Situation Room, which tracks the panic levels of all the contributing countries and keeps track of satellite coverage and council requests, as well as info on EXALT in Enemy Within.
  • Bittersweet Ending: Sure, you stopped the invasion, but at the cost of high civilian and military casualties (likely including some of your own troops) and the loss of the Volunteer (they're confirmed by Jake Solomon to not be dead, but they're still MIA), the most powerful psionic on Earth.
  • Bio-Augmentation: One of the new additions in Enemy Within. You can, for instance, make your units able to pull the In a Single Bound trope, or make them immune to panic and resistant to mind control.
  • Black Box: Most of the technology that the Science and Engineering departments come up with is this. They have no idea how exactly it all worksnote , but they can replicate most of it.
  • Black Shirt: EXALT is apparently made of these. They've been vying to Take Over the World for decades, and the political instability plus technological advancement opportunities provided by the aliens gave them just the opportunity they needed.
  • Black Speech: The language of the aliens sounds like Satan's autodial, complete with Voice of the Legion. The Chryssalids and Mutons add insectile chittering and roaring, and monstrous bellows, respectively. EXALT's encrypted radio chatter also sounds extremely alien and unrecognizable as human speech.
  • Blasting It Out of Their Hands: Higher level Snipers can do this with "Disabling Shot", forcing the target to waste a turn reloading the weapon to unjam it. The shot deals very little damage and has a flat 10% penalty on chance to land. Naturally, this only works for aliens with guns, and the guns of said aliens; other abilities like grenades or EXALT's rocket launchers will still work as usual.
  • Blinded by the Light: Flashbang grenades in Enemy Within leave enemies caught in the radius "Disoriented", with severe aim and movement penalties; this can cripple even the otherwise scary accurate Thin Men and Muton Elites into being unable to shoot straightnote , and Chryssalids into barely being able to move. Robots and psionic enemies are immune, though, including your own MEC Troopers and psionic soldiers under Mind Control.
  • Bling-Bling-BANG!: As of Enemy Within, changing a soldier's armor tint also changes their weapon's color. This can be realistic, as a soldier gets a woodland-color gun to match his woodland camouflage, but dressing your soldier in hot pink with yellow highlights will result in an equally ridiculous weapon. Although depending on the tint, a bug can make the weapon's color revert to the standard tint while in a mission.
  • Blown Across the Room: In Enemy Within, anyone killed by gunfire will be sent flying. If there's an easily destructible object (like a door) behind them, expect them to go flying hard enough to break it.
  • Body Armor as Hit Points: The primary benefit of armor is added HP, though some models also reduce the enemy's chance to hit. Certain special items like Nano-fiber Vests or Chitin Plating also boost health. Additionally, a soldier who receives less damage than the health bonus given by their armor won't need a stay in the infirmary after the mission. In Enemy Within, it goes a step further, as soldiers with the proper genetic enhancement won't regenerate past the base hit point value (i.e. without armor). Medkits still allow you to restore the entire health bar, though.
  • Bond One-Liner: Every time a soldier successfully stuns an alien.
    "Looks like you're coming home with us."
    "Not so tough now, are ya?"
    • There is also a hilarious variant if the stun attempt goes wrong and the alien is still standing afterwards:
      "Permission to use a REAL weapon, sir!"
  • Bonus Dungeon: Taking down and salvaging a Fusion Core from a Battleship-class UFO isn't necessary to complete the game, but you do get some sweet technology for doing so, including the Blaster Launcher.
  • Boss in Mook Clothing: Sectopods were always tough bastards, but fairly manageable if you knew what you were doing. In Enemy Within, they get upgraded with a trait that reduces all incoming damage by 50%, which doubles their effective health to 60, while simultaneously Nerfing "HEAT Ammo", which is their main counter, from 100% extra damage against robots to only 50%. Their Drone allies become even more of a pain, because the various buffs the Sectopod enjoys means that Drones can effectively erase any damage you do if you don't prioritize killing them first, and its abilities mean it's difficult to hack a Drone and keep it alive. Destroying just one Sectopod will take a lot of pre-planning, and even still often requires at least two full turns. The kicker? Late in the game, missions feature more than one, to the point where all the pods in a Terror mission can be Sectopods.
  • Book Ends: The game's opening begins with civilians watching as alien-built abduction devices fall to Earth as meteors. The game's final cutscene depicts the blasted remains of the destroyed Temple Ship falling to Earth as shooting stars while Earth's citizens look up in wonder.
  • Boom, Headshot!:
    • The first ability Snipers earn, which increases the chance of a critical hit and increases the critical damage dealt based on the tech level of the rifle used.
    • Shots that hit their target in general seem to be aimed towards the target's head. This is no guarantee that the shot will kill the target, however.
  • Boring, but Practical:
    • "Telekinetic Field". You have to forgo the more interesting Mind Control to get it, but it gives a Defense bonus equal to full cover that stacks with other Defense bonuses for all soldiers within its area of effect, including Smoke Grenades. Additionally, the field isn't Will-dependent like Mind Control, and the area it covers is massive, though unlike the UI representation it only works as a flat disc that doesn't affect units in a different vertical level than the userf.
    • The S.C.O.P.E., which gives a +10 aim bonus to the soldier using it. It is very cheap and available almost from the very beginning, and can be upgraded through the Foundry to also give a +10% critical chance. Even by end game, Snipers and Heavies will still get use out of them. There is virtually nothing better for the Snipers given the habit of leaving them as far back as possible, and thus, not in need of any additional armor, and unable to make efficient use of medikits and grenades; it also makes shots more likely to hit even against targets with very high innate defense, behind high cover or within a smoke screen. Heavies still need it to buff their mediocre Aim score of 75% at Colonel and is one of their few options to have the ability to score critical hits, which is normally 0% for them unless targeting a flanked or exposed non-Hardened opponent.
    • The Medikit. Can be used to heal 4HP to a friendly soldier or stabilize a critically wounded one. In addition, a soldier carrying one is immune to poison. Can be upgraded through the Foundry to heal 6 HP.
    • Support class soldiers. They're not especially extraordinary stat-wise, but they have access to a variety of useful abilities such as making Medikits much more effective with extra uses and more healing power, extra uses for all limited use items (in Enemy Within) or an extra 3 tiles of movement range. Nodded to by Bradford's description: "They make everyone around them better.". One single Support with Deep Pockets, Field Medic and Savior carrying a fully upgraded Arc Thrower is a MEC Trooper's best friend.
    • The Tactical Rigging Foundry upgrade from Enemy Within. Enables all soldiers from that point on to carry two items, in case you don't want to choose between two equally Boring, but Practical items, and puts the health-increasing items on the table for flimsier soldiers with choice items already like Medikits for Supports, Reaper Rounds for Assaults without Scatter Lasers, the S.C.O.P.E. for Snipers and Grenades for Heavies. Especially useful for covert operatives, who can't use armor.
    • The Ammo Conservation upgrade from the Foundry. All soldiers can make twice as many attacks before reloading. Not exactly glamorous, but damn near required to get full use out of Heavies and MECs.
    • Damage-wise, explosive grenades pale in comparison to the advanced tech you can have later on, but they remain a method for destroying cover and opening sightlines, mopping up weak or nearly dead enemies, or weakening a capture target just enough to use the Arc Thrower reliably on. With Damage Rulette in play, their fixed damage is handy when you don't want to risk a standard shot dealing only Scratch Damage.
    • Mindfray, the first psionic ability any soldier with "The Gift" automatically gets. While later abilities can allow you to do things like Mind Control your foes, chances are that Mindfray will remain a good choice because it recharges quickly and is often a 100% guaranteed 5 damage attack against many non-robotic low-Will enemies, even flying ones that can be hard to hit with conventional weapons.
    • Neural Damping, one of the genetic modifications, negates an otherwise successful Mind Control attempt by stunning the soldier, forcing them out of your control for a turn. Given the massive disadvantage mind controlled soldiers cause, this is a far better alternative than fighting against them for 3 turns or being forced to rush to kill the controlling alien. It also prevents panic, so it's a double bonus for low-Will units like the resident Shell-Shocked Veteran.
  • Bottomless Magazines:
    • Downplayed. Your squad members have infinite ammo supplies, but they have to regularly reload their primary weapons. Ammo is not tracked 'per shot', but in chunks dependent on the weaponnote  - and certain abilities (such as Suppression, Flush and Collateral Damage) use up more ammo than a normal attack. Played straight with pistols, that never need to be reloaded at all.
    • Played straight visually when using "Suppression". Until the turn is over, the soldier/alien using it won't stop firing, even if they've fired more standard shots than the magazine/powercell can normally allow. This is especially obvious with the "Training Roulette" Second Wave option from Enemy Within, where Sniper Rifles and Shotguns can be used to suppress enemies.
  • Bridge Bunnies: Gender inverted. All bridge personnel seen in the base view are male, though there is one unseen French speaking woman in the tutorial.
  • Bullet Time: Slo-mo effects occur when a reaction shot is triggered.
  • But Thou Must!: The tutorial mission helps you familiarize yourself with most of the mechanics of the game by taking your hand and telling you exactly what to do, guiding you to have all but one of your squad horrifically murdered. If you should play the tutorial again, there is absolutely nothing you can do to prevent this course of events, and the best you can do is skip the tutorial altogether*.
  • Bystander Syndrome: News blurbs in low-panic countries can report how tourists are attracted to locations with reported UFO sightings. Eventually averted, they start caring more as the panic rises and the Terror Site missions become more frequent, with the same news blurbs mentioning how some countries' tourism industries evaporated overnight.
  • Call a Hit Point a "Smeerp": The game uses a quite typical Class and Level System for your soldiers. While it does call classes "classes", the game being a gritty military type game, calls "levels" Ranks (as in, military ranks from Rookie to Colonel) and levelling up is called "earning a promotion".
  • Call-Back:
    • The report for the "Meld Recombination" research project mentions that Dr. Vahlen found a bunch of redacted files from the 1960s. The Bureau, anyone?
    • There's a strong implication that EXALT is the remnant of the 1960s XCOM, or is at least modeled after it for whatever reason. Note their old-style outfits and conspicuous backpacks.
  • Camera Abuse: The camera lens frequently gets spattered with gore during autopsies.
  • Canon Discontinuity: XCOM 2 revealed that XCOM canonically lost the war, quite early on at that, meaning that if you managed to win, it doesn't really count. However, that really only counts as Cutting Off the Branches, and XCOM 2 also provided the in-universe explanation that a successful campaign was a simulation happening within the Commander's head while a prisoner of the aliens, so the game itself is still actually canon. On the other hand, Enemy Within and everything that came with it (namely EXALT and Meld, but also additional enemy types such as Mechtoids and Seekers) was simply retconned out of existence and is never referenced again, even when you'd expect it would be. The only exception (and even that is theoretical) is the base assault mission, failing which is hypothesised to be what actually led to XCOM's defeat.
  • Can't Catch Up: EXALT eventually goes this way. Though their operatives field superior gene mods, they never reverse-engineer plasma weaponry or advanced armor, staying stuck on the laser/carapace tech level.
  • Cassandra Truth:
    • One news report states "UFO enthusiasts around the world feel sense of vindication following appearance of aliens."
    • New blurbs from countries at low panic will mention how reported alien sightings or people killing aliens are met with skepticism and accusations of drug usage, despite, you know, the whole alien invasion. This borders into ignorance if the country was panicking previously but has since calmed.
  • Category Traitor: The Council and Bradford specifically calls EXALT "traitors" rather than just enemies. For once, it's justified as they're humans trying to help the aliens conquer humanity.
  • Celebrity Paradox: One of the EXALT base location hints says that "It is/isn't in a country you can play in Civilization V," another game made by Firaxis. If it's not breaking the fourth wall, it confirms that Firaxis exists in this universe. One must wonder what their critically-acclaimed game released in 2012 must have been.
  • Changing Gameplay Priorities:
    • Your first upgrade can be either weapons or armor. At this stage in the game, your weapons are still killing enemies in one shot, so upgrading armor is more important as the aliens can often kill you in one or two shots as well. By the late game, you need to upgrade your weapons to compensate for the increased health the aliens have.
    • The first Terror mission, due to the heavy concentration of powerful melee enemies with lots of health. Before, successful tactics tended to involve getting into a good formation and creeping forward, staying in cover, and trying to take out the enemy from afar. Now, cover is useless, the enemy is too fast to stay far away from them for long, and you can't afford to dilly-dally lest they convert too many civilians into zombies, so your only hope is to kill them before they kill you. It can be a rude awakening if you've invested too much in long-range Snipers and not enough in close-range Assaults.
    • The higher difficulties can require different tactics both in the field and in the base. On Impossible, chances are good that until you get some heavy duty armor, nearly any non-hunkered down damage will be a one hit kill (and even then non-critical attacks can still badly hurt or kill you). So in that case you can focus on maximizing your offensive research and equipment in the hopes of having unstoppable Glass Cannon soldiers until you can get decent armor. Enemies cannot attack (other than ones that can't use cover going on Overwatch) on the turn you discover them, so if you only tackle one pod at a time it is possible to kill every enemy without ever getting shot at or hurt. As for the base, you'll lack useful things like the Officer Training School, meaning you may have to rely on the initial four squad limit more than you'd have to otherwise, as an extra soldier or two can make a big difference. Furthermore, panic from abductions becomes significantly harder to control, likely putting multiple countries into full panic by the end of each month. Rushing satellite production (and the prerequisite uplinks, power, and engineers) can feel damn near necessary as you can only afford to lose seven countries at most, which is only two to three game months of not rescuing full panic countries before you lose. And if you are rushing satellites primarily to save panicked countries, chances are you won't be able to clear entire continents at once, meaning you very well many have to do the Alien Base Assault and EXALT HQ Assault missions sooner for their global panic reduction even to save countries that already have satellites over them.
    • Tougher aliens and squishier soldiers on higher difficulties also make item priority shift from grenades to health-increasing items like the Nano-Fiber Vest and Chitin Plating. That way at least the New Meat should be able to survive more than a single burst of plasma.
    • "Damage Roulette", a Second Wave option where every non-explosive, MEC subsystem or psionic attack is a Randomized Damage Attack, makes critical hits and explosives the only source of consistent damage. With this in mind, it's perfectly viable to field ballistic weapons with the Reaper Rounds instead of lasers when going against high-health targets like Cyberdiscs early on. This ends up modifying research and engineering priority from weapons to armor, since even normally ignorable non-crit shots can one-hit soldiers with decent healthnote  if you're unlucky. In Enemy Within, the "can't crit on Squadsight unless on Headshot" penalty gives Snap Shot Snipers a more prominent role, as Headshot has a 1-turn cooldown. It also makes "Double Tap" and "Rapid Fire" more effective than against very high-health targets, just in case you need a certain alien dead and gone.
  • Character Customization: You can customize the visual appearance and names of the soldiers. Every soldier. All of them. The Elite Soldier Pack also allows you to customize the colors of their armor and includes alternate looks for standard XCOM body armor and Carapace Armor. Slingshot and Enemy Within add various types of headgear, as well as alternate looks for the other available armors.
    • It might have been even more involved at some point in development too, possibly having rookie soldiers with shiny untainted armor that would be altered as they rose through the ranks, adding some wear and tear and personal designs, much like actual soldiers.
  • Chameleon Camouflage: Mimetic Skin works this way in Enemy Within. If no aliens see their starting point (and would see the pattern moving), the soldier basically gets ghost cloaking if they move to full cover. It does disable the stealth mode of both Ghost Armor and Ghost Grenades even if Mimetic Skin isn't active at the time.
  • Cherry Tapping: Often necessary to capture aliens alive. While the most fragile of them can be taken down with just the Arc Thrower, the stronger ones need to be weakened first, which often necessitates that the squad pull its punches and intentionally use weak attacks to get them just low enough on health for it to work. The standard-issue sidearm pistols you start the game with (the weakest kind of firearm available) are often ideal for chipping away until a foe is at just the right number of hitpoints.
  • Chest Burster: Chryssalids.
  • Chest of Medals: Downplayed, but you can still give your soldiers up to 5 medals in Enemy Within, and they actually give them useful bonuses. There's also an achievement for giving all 5 medals to the Volunteer.
  • Clone Army: The alien troops are collections of genetic and cybernetically modified clones from a variety of species under the control of the Ethereals.
    • The game's customization, while good, is still somewhat lacking, meaning that your own forces can resemble this easily (or you can actually invoke it, giving them all the same face, hair, skin color, and voice.)
  • Les Collaborateurs: EXALT in Enemy Within. They're a pro-alien faction that opposes XCOM, and even though they're not in direct contact with any of the aliens, still seek to make things easier for them.
  • Colonel Badass: Colonel is the highest rank a character can achieve, and since ranks work essentially as levels, any Colonel you have is automatically this. Colonel-level abilities are often game-changers in their own right, like the Sniper's "In The Zone", which lets you shoot your entire magazine's worth of ammo in one turn as long as every hit kills a flanked or cover-less alien.
  • Color-Coded for Your Convenience:
    • The tech levels for weapons. Ballistics are khaki, Lasers are red and Plasma is green.
    • The option to change the color of soldiers' armor means that a player can manually do the same for his soldiers' classes, making them easy to identify at a glance.
    • Alloy Cannons, despite being in the "Plasma" weapon category, are yellow, possibly because they're actually ballistic weapons and don't fire plasma. The Assault soldiers carrying them still have the green insignia, though.
  • Combat Medic:
    • Any soldier you give a Medikit can qualify, though the Support class' abilities make them best suited for this role.
    • Thanks to the "Training Roulette" modifier in Enemy Within, any soldier has the potential to gain the "Field Medic", "Deep Pockets", "Revive" and "Savior" abilities, letting them heal as well as properly-specced Support Colonels in normal games. Even better if it's a Squadsight-build Sniper, who's unlikely to need to use medkits on themself.
  • Common Tactical Gameplay Elements: Being a tactical game, Enemy Unknown implements most of these: Fog of War, Scouting, High Ground, Unit Specialization, Panic, Attack Range, Flanking, Attack of Opportunity, Friendly Fire, Taking Cover, Covering and Suppressing Fire, Called Shot (Snipers only), Target Spotting, Defensive Stance (Hunker Down command), Crowd Control (Assault's extra reaction shot against nearby enemies), Concealment (Ghost Armor), Smoke Screen, Grappling Hook (Skeleton Suit and Ghost Armor), and Movement Manipulation (Assault's flush-from-cover shot).
  • The Computer Is a Cheating Bastard: Though the alien AI is quite intelligent and generally plays by the same rules, they do get a few one-sided advantages.
    • Enemy units get a free move to nearby cover (In Enemy Within, Cyberdisks, Mechtoids and Sectopods will go into Overwatch instead, while Seekers cloak before moving) when they are first spotted by one of your soldiers, unless said soldier is hidden by terrain or cloaking. This is to guarantee they can get into cover so they won't be easy kills, but they still get the free move even when it's already their turn, though they will be unable to do anything else for that turn either way. Needless to say, your soldiers don't get the same luxury, but luckily, they still trigger Overwatch.
      • This can be partially circumvented using the Ghost Armor, or, in Enemy Within, the Mimetic Skin gene mod or the Ghost Grenade. Any of these allows the cloaked unit to discover alien pods without automatically granting them their move to cover. Now, if you have a Heavy or grenade-launching MEC-trooper in range, you can remove those annoying packs of floaters and thin men in their entirety as they stand about, or give a Squadsight Sniper a free shot to pick off a dangerous unit standing out of cover. Melee aliens won't use it to get into cover, because they cannot take cover; they use it to get closer, even if they used their turn to get into visual range. If you're extremely unlucky, you'll spot them on the final move of your turn, and they use their free move to get very cozy with their next victim. Cue 'ALIEN ACTIVITY'.
    • An unfortunate bug can cause aliens to spawn right within your group entirely without reason or warning. This is due to the fact that enemy 'patrols' in the fog of war are nothing more than the groups of aliens sitting in a small group, waiting several turns, and then instantly teleporting to a different location on the map instead of actually moving around like they should.
      • Fixed as of Enemy Within: aliens now move around the map as they should, with defined, consistent positions every turn. You can even manipulate their movement with the Mimic Beacon to draw unseen enemies to a specific area of your choice.
    • In general, alien units follow the same rules you do: they can move twice, move once and shoot, shoot to end their turn, or move and set up Overwatch. Sectopods, being giant, massively armed war machines, can shoot twice and still catch your soldiers with reaction fire (but only if they don't move) in a single turn. Combined with their massive HP totals (more than any other unit in the game) and extremely high defense (-30% to be hit), they're incredible devastating when you encounter them, breaking the rules you've been following for the whole game. And the final mission throws TWO of them at you at once! Fortunately this is why the Volunteer was given the "Rift".
    • The AI is always aware of where your units are. Even if you move a unit between two points that no enemy unit can see, they will be able to reposition on their turn in an exact manner as to get a shot on the unit. As of EW, whenever possible aliens will pass within four tiles of stealthed units that they cannot possibly be aware of, provoking abilities like CQC for assaults. If you split your team to try to flank a pod (say, attack from two different doors to a room), its members will always move on activation in a way that maximizes their cover from all units. Enemies like Thin Men seem to have the uncanny ability to run exactly the right distance to enter your field of view (and subsequently, theirs) to fire on your troops without provoking overwatch shots, since overwatch only triggers when an already-visible enemy exits its current tile.
    • A strange case can be seen in Terror missions. Depending on sound cues, line of sight quirks and cloaking (especially notable in Enemy Within due to the early game option of Mimetic Skin), you might be able to "know" where untriggered and non-patrolling enemy pods are in relation to civilians, yet civilians can still die seemingly at random. That's because civilians in the fog of war have a chance of dying (and even getting zombified should Chryssalids be present) if enemies are merely present even if not actually attacking, and the higher you set the difficulty, the more civilians die each turn. Normally this AI shortcut would not be too noticeable, but there are cases where your entire squad could be covering all routes of entry for an enemy yet a civilian mysteriously dies in the fog of war behind a wall or something. Can be particularly nasty if a zombie sneaks up on you from behind this way.
  • Concealment Equals Cover: Zig-Zagged. Seemingly played straight, as all forms of cover only provide a Defense bonus (which reduces the chance of being hit) rather than reducing or stopping damage entirely, and can be shot through by any kind of weapon when the target using it is hit, essentially meaning all cover in the game is really being valued by their ability to provide concealment against shots. This means large garbage cans provide better cover than a low stone wall, and a bar tap or cash register is the difference between half- and full-cover. Averted by how nearly all cover can be destroyed by explosives or taking a direct hit by laser/plasma weapons, which makes it very clear the only purpose of the cover in the game is to provide concealment against enemy shooters. Played straight for conventional ballistic weapons when they shoot and don't hit their targets as the shots go into cover like the aforementioned large garbage cans, as bullets would logically tear through such materials.
    • Mostly kept the same in Enemy Within, though weapons can destroy cover even if the shot hits the target (previously, cover would be left completely unharmed if the shot hit the target) and heavier ballistic weapons, like LMGs and Sniper Rifles, can now destroy certain types of cover much like laser and plasma weaponry.
  • Conservation of Ninjutsu:
    • A pair of mutually exclusive Assault class abilities have higher benefits for having multiple enemies in sight. "Tactical Sense" increases the Assault's Defense, while "Aggression" increases their critical hit chance instead.
    • According to the game files, Easy and Normal difficulty allow a maximum of five alien units to be attacking you at a time. Classic and Impossible difficulty remove this restriction.
  • Continue Your Mission, Dammit!: If you're planning to unlock everything, you'd better be prepared for the Council to occasionally tell you to get the lead out on those story missions.
  • Cool Chair: EXALT has one in their headquarters. It is a huge ornamented throne-like affair, which is of course located in front of a huge holographic projection of the whole world.
  • Cooldown Manipulation:
    • Enemy Within lets you gene-splice soldiers with a neural feedback gene-mod; if an alien attacks them with psionic powers, all of the alien's abilities are put on cooldown.
    • MEC Trooper conversions: taking too much damage during a mission causes a soldier to be wounded, which can result in lenghty hospital stays that can last up to 8+ days. However, you can still put any wounded soldiers through a MEC conversion, which only lasts 3 days, allowing you to get them back to action much quicker if you don't mind losing any gene-mods they might have. This can be especially useful on harder difficulty levels where high-ranked soldiers are hard to come by due to their vastly lowered survivability.
  • Cool Plane:
    • The Firestorm, which can take on Battleships one-on-one and win. Dr. Shen, even with all the other cool gear he's built, says the Firestorms make him the most proud. Your Number Two also comments that humans have just leveled the playing field when he first sees it.
    • There's also the trusty Skyranger, which can bring your squad anywhere on the planet and back in a few hours at most.
    • The regular Interceptors are pretty cool too. They can take on highly-advanced UFOs without any reverse-engineered alien tech on them and win.
  • Cool Shades: With the DLC packs, soldiers get an option to wear these into battle. The added beret just enhances the coolness.
  • The Corruption: In Enemy Within, you'll have to be careful with all those genetic and cybernetic modifications, as things can happen to your soldiers when you use the aliens' Meld technology to genetically and cybernetically enhance them... at least, in story. They're perfectly safe to use as much as you want in gameplay*.
  • Cosmetic Award:
    • Mission ratings. While it's nice seeing Excellent across the board, the ratings themselves don't actually mean anything in-game, aside from the logical extensions of what losing troops (self-explanatory) or not killing all of the aliens (mission not completed and causes panic) hurting your ratings in their categories means. The exception is Terror missions, though, since the Civilians Saved rating affects how much panic is reduced afterwards.
    • Achievements.
    • Averted by the medals in Enemy Within: each one gives a specific, selectable bonus to the soldier to which it is awarded. A soldier with all 5 medals is significantly more effective on the battlefield than an equivalent rank soldier without any medals.
  • Cosplay: Played for Laughs in a news report from Japan as a cover-up. It reads, "Alleged alien abduction in downtown Tokyo has been blamed on costumed anime enthusiasts."
  • Coup de Grâce Cutscene:
    • If the cinematic camera triggers for an attack that kills someone, especially the Chryssalids' and Berserkers' melee attacks.
    • In Enemy Within, killing a Berserker, Mechtoid or Sectopod with the MEC Trooper's Kinetic Strike Module brings up a unique cutscene where the MEC Trooper beats them down.
  • Crapsack World: The in-game News Reports depict a grim picture of the world as panic starts to rise. Economic collapse, unchecked rioting, destroyed infrastructure, and starvation become common reports later in the game.
  • Creator Cameo:
    • One of the structures you can build is named after X-COM's original creators, the Gollop brothers (Julian and Nick). It is also mentioned that said structure was designed by a "pair of brilliant young brothers".
    • The Thin Men's facial features are based on Sid Meier himself.
    • Some of the Hero Units are based on Firaxis or 2K staff.
  • Crippling Overspecialization:
    • Heavies in general qualify - their LMGs pack a lot of punch compared to the standard assault rifles used by Assaults and Supports, and their rockets are not only highly effective against clusters of early alien bad guys due to their high damage and wide area of effect, but they also deny the tougher enemies their cover, leaving them vulnerable to be picked off. Heavies with the "Holo Targeting" skill are fantastic babysitters for low-ranking squaddies with bad Aim, helping them get those vital kills. By mid-game, you'll still find Heavies fairly useful in the role of fire support, but it'll be your Snipers and Assaults getting the big kill counts. They come back into use in the late game where HEAT Ammo gives them bonuses against the increasingly-common robotic enemies, but are nowhere near the killing machines they once were, even when you get the Blaster Launcher.
    • By choosing the appropriate abilities and equipment you could easily create highly specialized troopers of any class: supports that are great at healing and not very good at anything else, snipers that are great at long range with good positioning but terrible in close combat, and assaults that are great at close combat but very poor at a distance.
    • There are also plenty of equipment useful in a very specific situation and pretty useless otherwise.
      • Reaper ammunition is good before you get lasers, but are at most inventory filler for Council requests otherwise.
      • A ghost grenade is just what you need if you have a few exposed troopers standing near each other by the end of the turn and your other troops are much harder to hit; in other situations, it's not even worth using even when you've brought it.
      • Needle grenades are great for hurting plenty of enemies that do not have cover compared to where the grenade lands, otherwise it's a waste of Chryssalid corpses that you could be using for Chitin Plating.
      • Nano-fiber vests add 2 HP to a soldier's health pool. Useful very early on, but a drop in a bucket later on. The Respirator Implant does its job better and also negates the poison from Chryssalids and Thin Men and the strangulation attack of Seekers.
      • To a non-psionic, a mind shield is a great thing to have when facing psi attacks, but useless otherwise, especially if you have the right gene mods (Neural Damping, for example, negates mind control completely).
  • Creator Provincialism: Zig-zagged. Most of the time, in regular abduction, UFO crash, Terror! and equally run-of-the-mill missions, the battlefield will always look distinctly American. For instance, fighting in urban London will take place among (right-handed, naturally) black-white police car wreckages with red-blue lights, yellow cabs and Ford station wagons, crash sites "near the German border" occasionally look like the New Mexico desert, and Tokyo will be crowded almost exclusively by white and black people. But scripted story missions, like the tutorial in Cologne and the rendezvous in Hong Kong are usually surprisingly faithful to their locations, often including unique buildings, cars, NPCs and even traffic signs. Though admittedly, they actually made Cologne prettier than it actually is: you won't find many cobblestone streets and baroque houses there anymore.
  • Creator's Culture Carryover: No matter which country you deploy in, the buildings and cars (especially the yellow cabs) will often look like American cities or towns, not to mention the complete lack of accents for your soldiers prior to Enemy Within. And while EW does offer a new language customization options, all troops start out with English as their default language, and the language of many nations, such as Japan and Egypt, are not available. Occasionally, you'll also find maps which are inexplicably European or Chinese urban areas. Since each map is hand-crafted, however, this is understandable.
  • Critical Existence Failure:
    • XCOM soldiers and the aliens, as well as EXALT soldiers in Enemy Within, will continue fighting at full strength even if they're down to one hit point, though the former does take some temporary Will penalties. Can be averted for the former if the "Red Fog" Second Wave option is enabled, which reduces the stats of organic units as they lose health, though it can be reverted with medkits.
    • The XCOM project itself, if more than eight nations withdraw. You could be winning battles left and right with the best technology available, but skimp on the satellite coverage and you'll receive a message from the Council spokesman, not-so-subtly being manipulated by the aliens, that the entire project was a mistake and will be shut down.
    • Exaggerated in Enemy Within. Now whenever someone is attacked, they always flinch as the projectiles slam into their body. If they suddenly realize they don't have enough health to survive the assault, they'll go limp and be sent flying.
  • Critical Hit: Crits are a big part of the game, and likely will dictate most of your strategy.
    • A critical shot will deal significantly more damage, as listed in the weapon's info card, but use of cover and the Hardened perk (-60% chance of being critted) of enemies that can't Take Cover! make that difficult. Hunker Down is an ability that completely negates critical hits by sources that aren't flanking the user, though activating it reduces sight range.
    • Explosives, plain and simple, deal consistent damage but can't be critical hits. Neither can MEC subsystem attacks (Flamethrower and Kinetic Strike Module) (in normal ciscumstances; see "Absolutely Critical" below), for the same reason.
    • Shotguns have an inherent 20% crit chance that pairs well with the Assaults' tendency to sprint straight into the fray to catch enemies by the flanks.
    • Sniper rifles have an inherent 25% crit chance that goes up with tech level up to 35% with plasma snipers, and Headshot, that inherently grants +30% crit chance, is a Squaddie-level skill. In Enemy Within, Snipers got a nerf: using Squadsight can't crit unless using Headshot, which has a 2-turn cooldown.
    • Cheaper Foundry upgrades tend to increase critical hit chance, such as "S.C.O.P.E. Upgrade" and "Improved Pistols 1". Reaper rounds increase crit chance by 20% when used in the gun's correct range (not just "long range" as the description says).
    • Even more prominent with the Second Wave options.
      • With "Absolutely Critical", the crit chance on a flanked or exposed target is 100% and Hardened increases crit protection from -60% to -100% (which gives a net increase of 10% to critting a Hardened target). MECs benefit a lot from that: Flamethrower attacks and Kinetic Strike Module punches will always crit*.
      • With "Damage Roulette", a crit will deal the weapon's base damage plus whatever is rolled by the RNG. As such, going for a critical is a good way to try and avoid dealing Scratch Damage, with the chance to deal monstrous amounts of damage (such as a Particle Cannon shot critting for 25).
  • Crossover: The Brave New World expansion for Civilization V allows you to recruit XCOM Squads, end-game airborne infantrynote  that can take on even the Giant Death Robot, the strongest unit in that game. Each squad member wears Titan Armornote  and packs a Heavy Plasma.
  • Crutch Character:
    • The S.H.I.V.s are faster, tougher, better-armed and more accurate than Rookies, with mind control immunity and a variety of additional benefits to boot, but are outmatched by high-ranking soldiers. Nevertheless, their usefulness is such that many strategies for Classic and Impossible difficulties involve rushing to get them out the door ASAP. They're also extremely useful for Sectoid Commanders and above, as they can cheerfully laugh off almost everything the psionic enemies can throw at them aside from the Ethereals' "Psionic Lance" and "Rift", since S.H.I.V.s technically have 0 Will and will take, for example, a full 20 damage from Rift, which is a One-Hit Kill for even the Alloy and Hover ones.
    • The Argentinian Heavy, the Sole Survivor of the tutorial mission. He's your first non-rookie, but he's nothing special in terms of stats.
  • Cybernetics Eat Your Soul: In Enemy Within, MEC Troopers have a Machine Monotone and replace their combat banter with matter-of-fact acknowledgements. They also lose any psychic powers they had or might have been able to get. The upside? They get to run around in a Mini-Mecha with a BFG for an assault rifle and any other goodies you might have put on said giant robot.
  • Cyborg:
    • Floaters are more machine than flesh, especially the Heavy variant, as are the Mechtoids added in Enemy Within. Most of the other aliens are also this, though not nearly to the same degree.
    • XCOM MEC Troopers from the Enemy Within expansion, to an almost disturbing degree. The process for creating an MEC Trooper requires that they voluntarily amputate their arms and legs, have parts of their torso replaced with machines, and for battle, that they climb into monstrously large battle suits that are armed to the teeth. A lot of players likely flinched the first time they assigned a recruit to MEC trooper augmentation, and Dr. Shen offhandedly informed them that they'll be ready "once the requisite amputations are complete."
  • Cycle of Hurting:
    • A squad with low Will scores is particularly prone to this. A soldier could panic, and then easily do something suicidal like take off right into an enemy overwatch or hunker down perfectly exposed to the enemy, potentially getting themselves killed. Naturally, this can panic other squadmates, resulting in more suicidal actions that make it even harder to prevent more casualties. By the time every living squad member is calmed down, the mission can easily be rendered nigh-impossible or a guaranteed wipe.
    • Even worse are situations that do bad stuff to one of your high-level soldiers that then filters through to the low-level guys. For example: The Colonel gets mindcontrolled, which causes the Squaddies to panic... and shoot her. With their heavy weaponry. End result: One dead Colonel, two unresponsive soldiers, all from a single action of a single alien.
    • If a nation goes full-panic when it's already under one of your satellites, that means it brings you one step closer to losing the game and you've just lost a chunk of funding. That being said, there are strategies that gamble on losing seven out of eight nations while building up the military might to protect the rest.
  • Damage-Increasing Debuff: The "Shredder Rocket" ability available for Heavies. It causes enemies in the blast area to take 33% more damage from all sources for four turns, at the cost of doing less damage compared to a normal Rocket (though it still destroys cover). The debuff is not very useful early on (though a second rocket is), but potentially much more so later in the game when you start facing tougher enemies.
  • Damage-Sponge Boss: Come Enemy Within, Sectopods have an effective 60 Health, incredible damage output, and don't bother using cover due to possessing a permanent full cover bonus. Have fun.
  • Darker and Edgier: This game isn't necessarily darker than the original game in tone, and it even retains and modernises some of its 'action figure' aesthetics. That said, it also does take steps to make its presentation and art style a lot more grounded, perhaps best seen by the many Alien redesigns, or how XCOM's base is now a reasonably plausible industrial complex.
  • Death from Above: The Sectopods' "Rocket Barrage" attack. Though it takes a turn to charge up and offers you a chance to escape, it also can happen if the Sectopod is out of sight, meaning you often won't get a chance to.
  • Death or Glory Attack: A common tactic for players is sending a soldier out into the open in order to get a better shot or flank an enemy. Hopefully, the shots connect and the enemy will be too busy being dead to attack the exposed soldier. If it goes wrong, the alien is still alive at the end of the turn and retaliates, or you accidentally expose another group of aliens that proceed to cut down your trooper.
  • Decoy Protagonist: Delta Squad. They all have names (all soldiers do) and get to speak, but 3/4ths of them get killed before the tutorial mission is over.
  • Defend Command: Any unit able to take cover can use Hunker Down to double the defense value of the cover and become immune to critical hitsnote . The downsides are that the unit loses sight radius beyond the cover and the action is made void if the cover is somehow destroyed or the user is flanked.
  • Defiant to the End: It's possible to invoke this if you're losing. In addition, the scene of XCOM HQ if you lose the Base Defense mission looks like XCOM, Bradford in particular, put up one hell of a fight before going down.
  • Department of Redundancy Department: Standard missions in XCOM have randomly generated names made up of two words, such as "Operation: Fallen Tears". While most of the time these make no sense, some of them such as the previous one actually do. Although it's fairly uncommon to see, valid combinations could yield a name like "Operation: Vengeful Vengeance".
  • Depleted Phlebotinum Shells: A minor example in Enemy Within: reasearching Alien Materials or Weapon Fragments allows you to manufacture Reaper Rounds, which increase critical hit rate by 20% but double the weapon's aim penalty if used and naturally only work with conventional weapons. Since LMGs and rifles aren't subject to aim penalty and the said penalty only applies if you're using shotguns or sniper rifles outside of their optimal target range, they're useful early in the game to increase your potential damage output before you can research beam weapons. The Alloy Cannon is a more extreme example of this: according to its ingame description, while the weapon itself is just essentially a glorified shotgun, it needs to be made out of the same alien materials itself to prevent it from tearing itself to shreds when fired, while Reaper Rounds are implied to be experimental bullets with special casings.
  • Despair Event Horizon: Occurs to the populations of countries as the panic level maxes out. News reports state how many people give up hope for victory, and turn to religion, anarchy, or hunkering down in their homes. If the country then withdraws from the Council, they won't return from the brink. Additionally, the giant, red and black vortex of doom appearing over the affected country actually resembles an event horizon.
  • Difficult, but Awesome:
    • The basic Shotgun for the Assaults. While the Assault Rifle would be a better choice in the lower difficulties, it is a must in Impossible, where an instant kill is worth its weight in gold, and the Assault Rifle cannot reliably provide that even with a flank. The Shotgun requires careful placement of your Assault so that he's as close to up in the face of one alien while protected from the rest, which requires knowledge of how the cover and concealment system works.
    • Multiple high-rank MEC Troopers are this, due to how prohibitively expensive it is to field a single suit: 10 Meld to convert a soldier into a MEC Trooper, 40 Meld to build the basic MEC-1 Warden, 60 Meld to upgrade that into the MEC-2 Sentinel, and 100 Meld to upgrade that into the final MEC-3 Paladin. All told, it's a staggering 210 Meld to create and field a single fully upgraded MEC Trooper from scratch, which is a substantial amount, given that you can only collect 20 units of Meld during most missions until Heavy Floaters and Mechtoids start appearing in force. However, it's definitely worth it if you can collect enough Meld, as you get a Lightning Bruiser capable of taking on anything the aliens can throw at you if properly supported.
    • Fully gene-modding a soldier is also this. Depending on the options you take, five gene mods can cost between 150 to 200 credits and 80 to 150 Meld. They'll also take 15 days to go from unmodded to fully modded. However, when that's done with, you have a superpowered badass on your hands who can form an absolutely deadly duo with your MEC or even regular troops.
    • The Sniper's In The Zone ability can be this. Killing a target that has been flanked, out of cover or unable to take cover does not cost the Sniper an action, meaning that one Sniper can take down many aliens in a single turn. However, taking full advantage of this requires a lot of setup and luck.
  • Dirt Forcefield:
    • Played with. Your troops can run in the dirt or in muddy water, get wounded several times by aliens, survive explosions that blow walls apart, and walk in scenes of abominable carnage where walls have been repainted with litres of human and/or alien blood, but whatever they do, they will (mostly) look pristine and immaculate. Dirt, dust, and sweat never touch them. However, if they take more damage than their armor can handle, blood splatters will immediately appear on their uniform.
    • Played straight for the aliens, including species like Chryssalids and Berserkers, whose greatest hobby is ripping people apart with bare hands/claws/blades.
  • Disadvantageous Disintegration: Using explosives to kill aliens with weapons prevents you from salvaging anything other than their corpses after the mission, denying you weapon fragments that you could use in research projects or the foundry. Even worse, Heavy Floaters and Mechtoids in Enemy Within drop 5 Meld (that's half a lootable canister) apiece when killed by normal means, but if you blow them up, that Meld is lost.
  • Disc-One Final Boss Preview: You first see the Sectoid Commander during the tutorial mission. The next time you see it is when you're kicking down its front door during the Alien Base Assault.
  • Disc-One Final Dungeon: The "Alien Base Assault" story mission is, as far as the characters know at the time, a raid on the aliens' central headquarters on Earth, and is more unusual and more difficult than other missions to that point, complete with a Disc-One Final Boss at the end. Events shortly thereafter reveal this to be a mere staging area for the Alien Abductions, rather than their primary command center.
  • Disc-One Nuke:
    • MEC Troopers in Enemy Within. You're able to get your first one in as little as 21 days, long before your first Terror missionnote , they require only a relatively modest initial investment of Meld and money, and they have significantly more health and firepower than your rookies. You would need to research other things for many weeks before you'd be able to build lasers or carapace armor, so they're likely your first real power upgrade (gene mods don't really increase your ability to kill enemies, they just provide other nice benefits). Their only flaw is they're too big to Take Cover!, but they provide enough power and defense to keep the rest of your rookies alive long enough to level up. If you upgrade them and keep their weapons up to date however, they can become downright Game Breaking, as few enemies (even later on in the game) can withstand their attacks. Especially the Kinetic Strike Module, which is already powerful without the "MEC Close Combat" Foundry project that increases the punching power by 50% and allows the MEC to use it twice in the same turn as long as they don't move.
    • "Training Roulette" can be this trope if you get lucky. Your soldiers unlock a random ability after being promoted, and that pool includes the game-breaking Colonel abilities. Potentially, a support Lieutenant can heal as well as a Colonel, and a Corporal can get "Will To Survive", which reduces damage by 2 when not flanked against enemies that usually do only 2 damage. Even better, save for a few, abilities can go for different classes, like an assault Sergeant being as good a healer as a regular Colonel support with both Field Medic and Savior (and the perk of not giving up firepower when rushing to a patient thanks to Run & Gun), a guardian angel of a Sniper Lieutenant with Opportunist, Covering Fire and Sentinel/Rapid Reaction, or a soldier with Bullet Swarm and Executioner for constantly picking off wounded enemies. Combining Grenadier with Deep Pockets equals for Grenade Spam all day long.
    • With the Slingshot DLC, you can get your hands very early on a Plasma Rifle, as the Mutons you encounter will have them for sure instead of the weaker Light ones. In Classic or Impossible, one pops up in "Friends in Low Places" instead of the usual Chryssalid. If you manage to stun the Muton, you'll get the Rifle as well as the Muton for interrogation, which cuts down on Plasma weaponry research by half. With careful management, XCOM can more or less skip the bulk of laser usage in favor of the stronger plasma, especially if you couldn't capture a Sectoid to interrogate and give credit to laser research.
  • Don't Celebrate Just Yet: When the Alien Base is taken out, XCOM command staff start cheering, shaking hands and high-fiving. Even Bradford smugly says the aliens are finished. Dr. Vahlen is the only one not celebrating. She warns that her research indicates this isn't over yet. Boy, is she ever right. At this point the aliens start sending their heavy artillery like Muton Elites and Sectopods. And it's even worse in Enemy Within, as taking the Alien Base triggers the chaotic XCOM Base Defense mission less than a month later.
  • Doing Research: Very important throughout the whole game, as new aliens with different abilities and equipment show up as the invasion progresses. Performing an Alien Autopsy will provide more info when the alien is examined on the battlefield.
  • Double-Meaning Title: Enemy Within can be interpreted as referring to two of the major additions, namely Bio-Augmentation (Gene-mods use alien tissue, meaning the enemy is literally within) and/or EXALT (Human collaborators, the enemy within humanity's ranks).
  • Double Tap: While Snipers have an ability with that name, the credit actually goes to the Assault class's Rapid Fire ability, which shoots the enemy twice in quick succession.
  • Do Well, But Not Perfect:
    • Early on, if you capture too many enemies to steal their Plasma weapons and grenades for your troops to use you'll not have enough weapon fragments to advance your research. As such, you'll have to kill at least half of the enemies in every mission to ensure you keep them stockpiled. Enemy Within throws an additional wrinkle that you can't just build a squillion Plasma Rifles, Plasma Sniper Rifles, Heavy Plasma Guns and Alloy Cannons without running out of money and weapon fragments fast, so you now have more incentive to keep capturing enemies throughout the game and step it up in the late game once most weapons are researched.
    • In Enemy Within, the new medals system includes one, the Defender's Medal", that you can't unlock without allowing at least one of your troops to be killed or S.H.I.V.s to be destroyed. This means those who don't want to let any soldiers die can't acquire every medal.
  • Downloadable Content: Aside from releasing the pre-order Elite Soldier Pack bonus to the public, there's:
    • The Slingshot Content Pack, which includes a special series of Council missions and additional customization options for the XCOM troopers.
    • The free Second Wave, which includes 16 difficulty modifiers, some of which must be unlocked by completing the game on certain difficulties.
  • Dramatic Gun Cock: Snipers dramatically reload their ballistic bolt-action rifles after each cinematic shot, complete with a casing flying through the air in slow motion.
    • One-Handed Shotgun Pump: Assault-class soldiers do this after each cinematic shot... even if it's a laser shotgun. You gotta wonder if they added the pump to the Scatter Laser just for that (no other laser weapon has one).
  • Draw Aggro: The enemy AI usually prioritizes easy-to-hit targets. One tactic is to place units with high HP, Damage Reduction skills, and/or a Healing Factor, such as a MEC trooper, in the front of the formation to attract enemy fire. Additionally, if the player knows that an enemy is in Overwatch (which grants a reaction shot if a target in range moves), they can move an Assault with the Lightning Reflexes skill (which forces the first reaction shot that targets them to miss) or a unit far enough away to be difficult to hit first, triggering the reaction shot so that other units can move into position safely.
  • Dumb Muscle: Mutons fit the trope to a tee. They're physically imposing and have strong tactical knowledge, but aside from that, they're thicker than an asphalt milkshake and have no effective independence or initiative, depending on their mental programming instead. Fittingly, they have a Will score so low that any psychic soldier will easily mop the floor with them.
  • Dump Stat: There's little need to acquire additional scientists most of the time. Research gets done over time and can often by sped up simply by doing Council Missions. There's literally no need to build a Laboratory in Enemy Unknown. Science gets nerfed in Enemy Within, as more scientists are required to get research done swiftly, and a Laboratory can counter EXALT sabotage as well, but it's still far more prudent to focus on Engineers or money instead.
  • Dungeon Bypass: Quite a few, on both the enemy side and your side:
    • When outside of a building, Floaters can launch to any other point on the map. You might think you're being clever by trying to bait them into an overwatch trap, but it's possible they'll just launch past the entire trap and go behind your defensive lines, causing you to scramble to kill them or at least move into new cover before they flank you.
    • Chryssalids don't need to climb pipes or ladders like some other ground units and are instead able to leap straight up tall buildings In a Single Bound. This means that civilians and soldiers perched atop rooftops may not be as safe as they think they are.
    • In Enemy Unknown, your soldiers' options for bypasses are quite contextual until the late game, generally involving either going around a windowless portion of a building containing an ambush, climbing onto a roof and then dropping down on the other side, using the grapple feature of certain armors or expending some of your limited supply of explosives to clear a new path. In the late game, you can instead just use Archangel Armor and Hover S.H.I.V.s for truly bypassing terrain restrictions, doubly so with the Advanced Flight Foundry project that doubles the flight fuel for both and can potentially allow someone to remain in the air for the entire mission even if they fly around a lot.
    • In Enemy Within, you have quite a few more options: you can leap up tall buildings with the early Muscle Fiber Density gene mod, you can have a MEC with the jetboot modules skill rocket onto otherwise inaccessible ledges (potentially available even before Skeleton Suits), you can have a MEC use a Kinetic Strike Module punch or a Collateral Damage shot to blast through walls, or you could use the Mimetic Skin gene mod available much earlier than Ghost Armor to set up ambushes and more easily avoid triggering pods of enemies.
    • Perhaps the most literal dungeon bypass can be found in the Site Recon mission in Enemy Within. Normally you'd have to trudge past a hive spawning Chryssalids and take quite a few turns to walk up the stairs of the ship and get to the transponder. Flight is an obvious bypass, but not one you're likely to have by the time the mission shows up. However, both Muscle Fiber Density and armor with grappling capabilities (most likely Skeleton Suit) could be available to you if you see this mission in the early to mid game. With either of those, you can just leap or grapple up to the top deck of the ship from its entrance and be very close to the transponder. Chryssalids are mobile enough that it's not fool-proof (you'll still probably want other soldiers close by to thin their spawn numbers), but it can at least save you multiple turns getting to the transponder otherwise.
    • Subverted with the Slingshot DLC, that allows you to capture a fully intact Battleship in the first month of gameplay, netting you crazy amounts of resources and technology, including the Fusion Core. The time needed to research it at that point, with a small science team and no bonuses, is extremely prohibitive; never mind that the two uses for researching them, the Fusion Lance and the Blaster Launcher, both need a huge amount of extra research to be put to use.
  • Drop Ship: The Skyranger is a crude one. Though it doesn't seem to actually go into space, the speed at which it moves around Earth does suggests that it's using sub-orbital spaceflight. In its role, however, it fits the trope like a glove.

    E-H 
  • Early-Bird Boss:
  • Early Game Hell: Until you get some upgrades, don't expect your soldiers to do much more than die horribly unless you're good and/or lucky. Even harder is finding the time and money to build anything in your base. But the worst aspect of early game is managing the panic rating. Until you get universal satellite coverage, you'll have to deal with a constant stream of alien abduction missions that substantially increase panic in the continents you can't reach.
  • Easy Level Trick: The Final Battle can be won in a very anticlimactic way by sending in a mimetic-skinned Sniper packing plasma heat and the Double Tap skill. There's cover aplenty to activate their cloak, the Uber-Ethereal is an easy target that won't do anything because they have no target in sight, and two good hits from a plasma sniper rifle are enough to kill them, starting and ending the battle in the same turn. Actually getting there in the first place is the tricky part, however, considering the Marathon Level that comes before.
  • Easy Logistics: Much easier compared to the original XCOM.
    • Ammunition is never a matter you need to personally provision, and aircraft fuel is managed for you behind the scenes. About the only things you need to manage supply-wise are the quantity of XCOM-original advanced weapons/accessories that you research and produce, as all conventional human weapons/supplies are readily available.
    • Any alien corpses, enemy weapons and recovered UFOs are instantly transported to your base upon completion of a mission, with no mention of just who is coming in behind you to dismantle the UFO, pack everything up and ship it back to your base – sometimes from the other side of the planet – on a moment's notice. You also don't have to worry about having proper storage facilities for alien corpses, power generators, Elerium, or anything else you recover. It's merely held for you until you're able or willing to use it for something.
    • One less obvious logistics-related thing is that you need to make sure that you have an Interceptor available at every continent that can detect UFOs via satellites, or you won't be able to actually shoot them down once they're detected. Transferring any extra Interceptors to a new continent takes as much time as the delivery of a newly-purchased one.
  • Elaborate Underground Base:
    • The XCOM Project's headquartered in one. Instead of the classic top-down view flat base, this game uses a side-view multi-level base nicknamed the "Ant Farm". Unlike the original game, this is the player's only base; the developers noticed most XCOM players focused on a single base and built others solely to expand their radar range, which is done via launching satellites in this game.
    • The aliens have one too, using it as a gathering points for specimens from all the Alien Abductions they have been doing. The Disc-One Final Dungeon consists of raiding this base.
  • 11th-Hour Superpower: For the final mission, the Volunteer gets a powerful area of effect attack called "Rift". However, the Ethereals have the same power as well, although they rarely use it.
  • Elite Mook: Quite a few.
    • Sectoids -> Sectoid Commandersnote 
    • Floaters -> Heavy Floatersnote 
    • Mutons -> Muton Elitesnote 
    • EXALT -> EXALT Elitesnote 
  • Elites Are More Glamorous:
    • In this case, it's all of XCOM that are the Elites. XCOM is the special unit that gets the critical missions, the best equipment, and ends up booting the aliens off the planet. In the meantime, the appearances of the regular Earth militaries are restricted to requests for gear to not get curb-stomped, flavor text stating how they're getting curb-stomped, and missions showcasing how they're getting curb-stomped. A Council mission involves rescuing an official from an alien ambush. When you reach him, he always comments on the quality of your equipmentnote , even if you're using basic equipment.

      This is accentuated during the defense of the XCOM HQ, where you have access to XCOM base security as well as a few of your standard operatives. The difference is stark, to say the least. The base security is little better than your standard rookie, and by this point in the game you're fighting things like Chryssalids, Mutons and Sectoid Commanders.
  • Emergent Narrative: The game is unusual in that its procedurally generated individuals (your alien-busting squad) are not artificially intelligent. However, they are just individuated enough (through appearance, names, nationalities, and, eventually, classes, call signs, and Psychic Powers) and their battles are sufficiently random that most players become emotionally invested in their advancement and survival, and have at least one story to tell about that one soldier who survived against all odds again and again to save the day in the final mission.
  • EMP: The EMP Cannon is a fighter-mounted weapon that can be used to shoot down a UFO without doing significant physical damage. It gives you the chance to recover as much usable alien tech and materials as possible, but using the weapon means the fighter has to get very close to the UFO, while dodging enemy plasma shots. More useful with the Firestorm, which can withstand a lot more hits than the regular Interceptor. It is powerful, though, and can shoot down a Battleship-class UFO in two-three hits.
  • Empowered Badass Normal: Your super-soldiers, who started off as mere rookies and can now Mind Rape aliens to death, leap over entire buildings with their genetic enhancements, or operate a Mini-Mecha that Rocket Punches aliens to death.
  • The Enemy Weapons Are Better: Stunning heavily armed enemies with the Arc Thrower is the way you get Plasma hardware of your own; in fact, Enemy Within actively encourages you to do this by jacking up the credits and material costs of manufacturing Plasma weapons of all kinds, so stunning Sectoids and Mutons isn't an absurd proposition even after you've interrogated previous captives. EXALT's lasers can also apply if your beam weapons production has taken a backseat, though they're unusable if you haven't researched the principles behind each weapon type.
  • Energy Weapon: The second tier of weaponry available to XCOM is laser hardware. They're not as powerful as their plasma counterparts in most cases, but they're a step up from regular ballistic weapons and much cheaper to build than anything that fires plasma. In Enemy Within, lasers are the go-to of EXALT Elites.
  • The Engineer: Dr. Shen and everyone else in Engineering. There's also a military Combat Engineer, Sergeant Carlock, in a Council mission.
  • Enhanced Interrogation Techniques:
    • XCOM "interrogates" alien captives. We aren't shown the details (as a shutter closes when interrogation starts), but it involves two arms radiating some energy, getting information straight out of the alien's brain and lots of sedatives. Also, the subject never survives the process and you always get their corpse added to your stockpile after the interrogation. After the first Sectoid interrogation, Dr. Vahlen is asked how exactly they interrogated an alien who speaks a language nobody understands. She replies that they stuck probes into its brain and read what signals they could until it died. Yikes.
    • Subverted with the Berserker Interogation, which apparently started with the brain-probing to figure out a way to calm the thing down, and then had it run a series of physical tests. Presumably, the risk of having a Berserker around meant it was simply killed afterwards. Likewise, the Heavy Floater Interrogation seems to involve figuring out how to puppet it mentally, then having it run tests, as neither has much in the way of actual knowledge desired by XCOM. Indeed, the research credits they give are related to their physical capabilities (Armor for Berserkers and Flight for Heavy Floaters).
    • Not to mention South America's continent bonus - "We Have Ways", making both Interrogations and Autopsies instantaneous, banking on the reputation of certain South American dictatorships and their employment of these.
  • Escort Mission:
    • Target Extraction Council missions. Unlike just about every other game ever, the Escort is fully controllable and has a special ability that raises their defense, though only if they're in cover and haven't dashed to get to said cover. It's a bit strange in the case of one potential escort, who protests loudly about being extracted against his will by XCOM while the aliens gleefully shoot at him; presumably he plays like the others because of gameplay limitations, or because having to have a soldier push him around would be too much of a hassle to be enjoyable.
    • Covert Extractions in Enemy Within play like this. The covert operative has to hack a few comms relays and hightail it to the Skyranger, and it's up to the rest of the squad to protect them or the mission will be a failure. The kicker is that the operative is one of your own soldiers, toting a pistol and whatever items you gave them when you sent them off, plus whatever gene mods they had implanted. A high-ranked soldier with a Plasma Pistol can be a bigger, tougher and badder unit than most in the extraction squad sent after them.
  • Every Car Is a Pinto: Unsurprising, given how many laser and plasma weapons are getting thrown around. Typically, they have to be set on fire first before that happens, which also gives both the XCOM troopers and aliens one turn to get away from it, though explosives and the Collateral Damage MEC skill will immediately cause it to blow up. Furthermore, stray missed shots from plasma and laser weapons can set vehicles alight, even from across the map, leading to seemingly inexplicable explosions a turn or so after a unit with laser or plasma misses a shot.
  • Every Bullet is a Tracer: Ballistic weapons. Even more pronounced if the soldier has Reaper Rounds, whereupon the bullets look like small red stars.
  • Evil Counterpart:
    • Mutons have been described like this, an alien SEAL Team Six to fight your own troops. For starters, they're equipped with Alien Grenades, and they will use them on groups of your XCOM troops.
    • EXALT from Enemy Within: a pro-alien terrorist group that uses the same classes, equipment and abilities as XCOM and also reverse-engineers alien technology as the campaign goes onnote . They even have their own holo-globe, except red instead of blue like XCOM's version.
    • Mechtoids, Sectoids mounted in a Mini-Mecha, are essentially the alien counterpart to your own MEC troopers.
  • Evil Laugh:
    • Psionic troopers will sometimes break out an absolutely blood-curdling one when using the Mindfray ability on enemies. Makes you wonder if Dr. Shen is right...
    • All of the aliens celebrate their accomplishment when they kill someone, but the Heavy Floater always seems particularly amused with himself after he blows away one of your soldiers or a civilian with his plasma rifle.
  • Evil Makes You Ugly: EXALT genetic modifications exceed even Dr. Vahlen's ethical limits, and it shows. Elite EXALT operatives display deep wrinkles, sunken eyes and some even have greenish skin discolorations. Their regular operatives aren't in much better shape either.
  • Executive Suite Fight: EXALT's headquarters is in a luxurious penthouse on a skyscraper, so naturally the raid plays out like this trope.
  • Exposed Extraterrestrials: The Sectoids.
  • Expospeak: During the final mission, Strike One faces every enemy type there is in increasing order of lethality while the Uber-Ethereal regales the Volunteer with some exposition on how each of them was subjugated by the Ethereals, and why they ended up considered failures in their eyes. It mostly just confirms what Vahlen and the player already deduced by themselves over the course of the campaign, but it's a nice touch anyway.
  • Face Death with Dignity:
    • Out of all of the aliens that get interrogated, the Thin Man is the only one who doesn't panic. He glowers at the zappy-arms and starts walking towards the glass as if he's about to say something, but the shutters close on him before he says anything.
    • The Ethereal attempts this, standing aloof and dignified in the containment before it starts, but loses its composure as soon as the robot arms move in. Unlike their lesser cannon fodder, the Ethereals never expected humanity to capture them, after all.
  • Face–Heel Turn: It's hinted that EXALT is the remnants of the 1960s XCOM, which means they've gone from fighting the invaders to collaborating with them in hopes of taking over the world in the wake of the invasion.
  • Faceless Goons: You can have your own squad of them, provided you have the Downloadable Content.
  • Fast-Roping: Used in the intro of a couple of story missions in Enemy Unknown, and an uncommon entrance during certain regular missions in Enemy Within.
  • Fate Worse than Death: said word for word by Ethereal Collective regarding Floaters.
  • Fighter-Launching Sequence: When an Interceptor, a Firestorm or the Skyranger is launched, we are treated to a cutscene of its launch. The cutscene is longer the first time it's done. Each subsequent time, only the last part of the cutscene is played.
  • Fighter, Mage, Thief: The three Super Soldiers you can get each correspond to an archetype.
    • MEC Troopers are the Fighter. They are big, bulky, and cannot take cover. Instead, they become the cover for your teammates, and they're equipped with the heaviest weapons possible, from BFG to Power Fist, allowing them to charge straight into the battle, match Berserkers and Sectopods in brute strength, and pound them to submission.
    • Gene Mod Soldiers are the Thief. They get options that enhance their ability to work independently of the team, sneak behind enemy lines and deliver critical damage to the enemy before they even know what hit them.
    • Psionic Soldiers are the Mage. They bring otherworldly arcane power to the battlefield, which can truly disrupt the enemies. They lack increased durability or survivability, unlike MEC and Gene Mods, but with powers such as Mind Control or Rift, they won't need that extra survivability.
  • Final Death Mode: Ironman mode. No reloading on death.
  • Fishing for Mooks: Enemy groups lurk in the Fog of War until encountered, at which point they attack, so a common strategy is to creep forward attempting to reveal and destroy enemy groups one at a time. The Expansion Pack adds a new resource called Meld that self-destructs if not collected quickly in order to reward players who eschew this strategy and explore more aggressively.
  • Flawed Prototype: Almost every alien type you encounter throughout the game were enhanced by the Ethereals, but fell short of their expectations one way or another. Sectoids are gifted with psionic abilities, but are physically fragile and cowardly. Thin Men are highly intelligent, but cannot use the Gift. Cyberdiscs combine the strengths of organics and machines, but lack higher thinking. Floaters are merciless, mindless killing machines. Chrysalids were uplifted from primitive insects, but have become more of a liability than an asset. Mutons are possessed of overwhelming strength, but are lacking in intelligence or independent thought. Sectopods were built to supplement their forces, but serve little purpose otherwise. Drones and Outsiders are simply tools, and were apparently never supposed to be anything important.
  • Foreshadowing:
    • The Tutorial mission hints at all of the iconic alien species you'll encounter later: a soldier that has been torn open from the inside out by a Chest Burster, a zombie trapped under some rubble, and a psionically mind controlled soldier will all be warning signs to long time fans.
    • Over the course of the first Operation Progeny mission, there's several to the entire EXALT faction. Bradford notes that the ambushed French soldiers were killed with ballistic weaponry, they're after a very special "cargo," and you extract someone who is implied to be an EXALT operative, who gives cryptic hints to his organization's ideology and opinions on XCOM.
    • After playing through the entirety of Enemy Within, the opening quote by R. Buckminster Fuller sounds like pointless alarmism. Then you get to XCOM 2, and the true meaning of the quote becomes clear...
  • Freeze-Frame Bonus: Take a good look at the map coordinates during the cutscenes showing the first downed UFO and the Alien Base's location. They actually point to 2K Games' Corporate Headquarters in California and Firaxis' Game Studio in Maryland, respectively.
    • If you look carefully at the ending cutscene of the final mission, you can see that the Volunteer disappears in a purple flash right before the Temple Ship explodes. This appeared so briefly that virtually everyone thought the Volunteer died until Jake Solomon pointed this out on Twitter.
  • Fun with Acronyms:
    • The Super Heavy Infantry Vehicle.
    • The S.C.O.P.E. item. The game never mentions what that stands for, and it looks just like a fancy scope.
    • XCOM itself is never explained in-game; it stands for eXtraterrestrial COMbat unit.
    • Mechanized Exoskeletal Cybersuit, in Enemy Within.
    • In Enemy Within, there's EXALT, which, like the S.C.O.P.E., never has its meaning mentioned.
  • Freudian Trio: Dr. Vahlen (Id), Dr. Shen (Superego) and Officer Bradford (Ego).
  • From Bad to Worse: Countries that lose faith in XCOM due to high panic levels will withdraw their funding to focus on their own defense. After which, a swirling dark vortex emerges over the country. Not only that, running covert operations against EXALT in these areas puts you in a mission where you see a lot of destruction; which heavily implies that country is essentially overrun.
  • From Zero to Hero: Every soldier in the game is recruited as a level 1 newbie with no special qualities, but in the final act, one of them will become the Volunteer, the most powerful human psychic on the planet who sacrifices themselves to thwart the ongoing alien invasion.
  • Gas Mask Mooks: Mutons have some sort of breathing apparatus and some of the DLC helmets for your soldiers can count as well. However, neither protects against poison cloud attacks. For XCOM soldiers to have poison immunity, one must wear Titan Armor (Ghost and Archangel as well in Enemy Within), carry a Medikit or carry a Respirator Implant (Enemy Within-only).
  • Gatling Good:
    • The SHIV's and MEC Trooper's default weapon is a ballistic minigun.
    • Interceptors can mount a short range rotary cannon called the Phoenix Cannon.
    • The Heavy Laser has three "barrels" at the front that spin as the Heavy fires it.
  • Game-Breaking Bug: On Ironman, bugs that would normally be of the "annoying but minor" variety (since you can just reload the game if they screw you up too badly) can reach gamebreaking status if they happen at the wrong time, and campaign enders if on Ironman.
    • The flight movement interface is... iffy, to say the least.
      • It's possible to get soldiers and S.H.I.V.s trapped inside objects where they can't move to escape, which in gameplay terms is like killing them (at least for the mission). If they turn out to be the sole survivor, you can't save them at all; you must abort, restart or use the console to teleport the unit to a valid square.
      • The same goes for the aliens. A Floater, Drone or Seeker may fly up and clip into the ceiling and out of sight of all soldiers; the alien itself will either be able to attack with impunity or incapable of seeing your troops in return. This tends to happen in the bridge of a Battleship, and in most cases can only be fixed by firing a blind airburst rocket in hopes that it kills the ayy. If it's a healthy Heavy Floater, though, if you don't have an extra rocket, you're softlocked.
    • Using "Disabling Shot" on an alien in Overwatch has a chance to produce the exact opposite effect. They won't be disabled at all the next turn, and then get unlimited Overwatch shots, shooting at a target each tile it moves, which can often doom that soldier.
    • The infamous "teleporting alien" bug, which can drop pods right into the middle of your unprepared team. If you're on Ironman and get a nasty group popping up in the middle of your team (such as a Sectopod), you've pretty much lost the mission unless you're really lucky.
    • Using a smoke grenade in the final level on the area overlooking the two Sectopods can cause the game to freeze if the Sectopods are still alive.
    • Covering Fire triggers reaction fire when a soldier uses the Skeleton Suit/Ghost Armor's grapple hook. For bizarre reasons, the grappler will be sent flying far in a random direction after the reaction shot is done, frequently straight into the ground, into mid-air or even outside the map boundaries. For this reason, it's better not to grapple in front of an EXALT Medic of any tier or Mind Controlled Support, otherwise get ready to abort the mission, count that soldier out of the battle, or use the console to teleport them to a valid position.
    • In Enemy Within, if a soldier with the Neural Damping gene mod has been set on Overwatch and is knocked unconscious due an attempt at Mind Control, the game engine will keep the Overwatch flag up on them. If an enemy moves within the KO'd soldier's line of sight, they'll technically still try to fire at enemies, but can't due to the stun. This softlocks the game.
    • On the PC version, its possible for the launcher to never show up at all when you try to play the game, especially on the Steam version. This makes the game unplayable.
  • Game Mod: Although neither EU nor EW natively support modding, knowledgable players quickly provided countless mods that tweak or rebalance the gameplay, fix bugs and annoying mechanics, add more customization options for your soldiers, or even overhaul the entire game. It's also fairly easy to adjust pretty much anything to your liking on your own by fiddling with the various INI files, which are simple, well-commented text files.
  • Gameplay and Story Segregation:
    • Dr. Vahlen asserts that the hulls of alien ships must be at least an order of magnitude stronger than any currently-known material. They are easily destroyed by garden-variety hand grenades. She also seems to neglect that interceptors are capable of shooting the UFOs down with conventional earth weaponry.
    • Someone on Reddit tried to put the game's logic in a realistic context.
    • The Sectopod is described as being 10 meters, or FOUR FUCKING STORIES TALL. While certainly the largest unit in the game, its model is no more than twice the height of your human units. XCOM 2 makes it clear that Vahlen meant when they're standing up: the Sectopods in this game don't (or can't) do it.
    • The first mission of the Slingshot DLC has you escort and extract Shaojie Zhang, a member of the Triads who wants to defect and is carrying some vital intel with him. Bradford will warn you that both the aliens and Zhang's former superiors will want to come after him at the start of the mission, but human enemies wouldn't get introduced until Enemy Within, meaning all you face are the aliens. Zhang becomes a permanent member of XCOM if the mission is successful, but the remaining two Slingshot missions deal with the threat of an alien battleship, while the Triads never get mentioned again.
    • Speaking of Zhang, his introductory cutscene shows him adeptly killing a Sectoid with a pistol. He is guaranteed to always become a Heavy upon joining XCOM, the only non-MEC class incapable of using a pistol.
  • Giant Mook: Mutons in general, as well as Heavy Floaters. As of Enemy Within, Mechtoids, which are Sectoids piloting a Mini-Mecha. Sectopods are this in Enemy Unknown, but re-tooled to be a Boss in Mook Clothing in Enemy Within.
  • Glass Cannon:
    • The Sniper class is decently fast but can't fire their sniper rifle at all after moving, unless a specific class perk is taken, and also has lower base health progression than the other classes. Considering their weapons have the highest accuracy and base critical rate, and that they can have an array of severely overpowered perksnote , it's entirely possible to kill or severely wound some of the strongest enemies from across the map.
    • Seekers are dangerous because they cloak, hide for a few turns, then incapacitate and strangle an isolated unit to death if no other soldier can reach them in time. Once they are revealed, they have pathetic HP pools for an armored robot and easily fall prey to even ballistic weaponry.
  • Glassy Prison: Constructing one of these is an early objective, and you are treated to a brief cutscene of the captive alien inside it whenever your team brings in a sample of a new species alive.
  • Global Currency: XCOM, no matter where in the world it's located, uses Credits instead of the national currency of any of its founding nations. This is presumably to make it easier to quantify and streamline the calculations of funding, supplies and logistics if a single unified currency is used instead of being forced to calculate exchange rates. And it also probably saves a lot of zeros—if that fully-autonomous treaded combat robot costs "§50" to make, you can bet "§1" is a heck of a lot of dollars or euros.
  • Glowing Eyes: Using a psi ability causes the user's eyes to glow a sinister, deep purple.
  • Godzilla Threshold:
    • Implied with Dr. Shen's No Transhumanism Allowed stance on Psi Testing in Enemy Unknown. Exaggerated in Enemy Within with Gene Splicing and Cybernetics thrown on top of the pile.
    • In a more meta example, explosives. Grenades and rockets are extremely powerful weapons that are available immediately, but destroy valuable alien equipment you could otherwise salvage; as a result, they are rarely used in Easy and Normal. On Classic or Impossible, explosives aren't just a good idea - they're pretty much mandatory.
  • Gone Horribly Right: As it turns out, the XCOM project as a whole. The Ethereals invaded to motivate the creation of the project so they could weaponize the inherent versatility and Determinator outlook of the human race so we'd be useful enough to adopt as part of their alien empire and help them with something that's coming. Assuming you win, it worked too well.
  • Good Weapon, Evil Weapon: The dimorphism between XCOM's and EXALT's weapons becomes more pronounced later on in the tech trees. At first, EXALT starts with black-tinted ballistic weapons, compared to the khaki camo your soldiers default to. For the lasers, they're black to your light gray and shaped more like typical guns repurposed to fire lasers than your own laser guns. Subverted in that XCOM can equip EXALT's weaponry to no ill effect – functionally, they're the exact equivalent to your own hardware.
  • Gotta Kill Them All: Most individual missions are played this way – to succeed, you have to kill or disable every alien in the zone. There are a couple of Escort Missions where you just have to get one character to the exit area (possibly with a couple of tasks on the way), and to win the final mission and the game, you just need to kill one particular alien (though it's hard to get to him without killing almost every other alien on his ship).
  • The Greys: The Sectoids are back of course. By way of the Dover Demon and Deus Ex, by the looks of things.
  • Grand Theft Me:
    • It's implied that the reason behind the alien invasion may be to use humanity as the new host bodies for the minds of the Ethereals, whose current physical forms have deteriorated almost to the point of uselessness.
    • Can be done in-game to both organic aliens and your soldiers using psychic Mind Control.
  • Grappling-Hook Pistol: A built-in version in the Skeleton Suit and Ghost Armor. Exceptionally useful for snipers.
  • Grenade Spam: Possible in Enemy Within thanks to the new abilities, items and inventory system. A properly-specced Support could potentially bring in 3 smoke grenades and two pairs of different grenade types. A Heavy can bring 2 rockets, a shredder rocket, and 2 pairs of any grenade.
  • Guide Dang It!: It would've been helpful if Dr Vahlen had clarified that an enemy's loot is only destroyed if the killing blow specifically was done with explosives.
  • Guns Do Not Work That Way: XCOM operatives tend to be rather lax about gun handling.
    • Assaults cycle their shotguns one-handed, by holding it by the pump and shaking it. They do that even with the considerably bulky Alloy Cannon.
    • Heavies hold their machineguns properly until they have to shoot them, at which point they hip-fire it while holding the front end by the carrying handle.
    • Snipers use an odd "wrap-around" posture when aiming their rifles. It's also halfway in Reality Is Unrealistic, as the posture does exist in real life... it's just that it's used when prone and using a bipod for extra stability.
  • Hack Your Enemy: Drones can be hacked with the Arc Thrower once the "Drone Capture" Foundry Project is completed. It's a permanent side change, too, unlike the 3-turn limited Mind Control. Hacked Drones can repair S.H.I.V.s and MEC Troopers.
  • Hand Cannon: The Plasma Pistol is easily the largest handgun in the game, and it's just as large as it is powerful. With all Foundry projects researched and on a soldier with Gunslinger, it easily rivals the Light Plasma Rifle.
  • Harmless Luminescence: Flashbangs will disorientate aliens and their allies, but will do nothing to your own soldiers.
  • Heal Thyself: Played with. While healing items and regeneration abilities immediately replenish the lost HP, the soldier will still need infirmary time if they lost health points not added by their armor.
  • Healing Factor: Many in Enemy Within.
    • The "Adaptive Bone Marrow" Leg genemod allows your soldiers to heal two HP per turn once their actual health (the base value, what the armor gives doesn't count) is damaged, while also reducing their recovery time after the mission by a considerable amount.
    • EXALT Elite Medics have an ability to automatically regenerate one health per turn, which also affects nearby allies. This ties into an achievement called "Regenerate This!", if you use an explosive device to kill them.
    • MEC Troopers can choose the "Repair Servos" passive at Captain, which lets them repair 2HP per turn, up to a maximum of 6HP per mission.
    • S.H.I.V.s can repair 2HP per turn after completing the "Sentinel Drone" Foundry Project. Unlike MECs, there's no limit to that, but if they tank a crit, it's disabled.
  • Healing Shiv: A Foundry project allows the Arc Thrower to heal any robotic allies (S.H.I.V.s, MEC troopers and hacked Drones), for the value of an upgraded Medkit (6 health). A soldier with Deep Pockets and Field Medic can extend a MEC trooper's survivability by 42 health points, or 58 if s/he also has Savior.
  • Heavily Armored Mook: Elite Mutons and Berserkers both have heavy armor, but the biggest example is the Sectopod, which has a whopping 50% damage reduction and 60% critical hit resistance. Anything less than plasma weaponry is about as effective as hitting it with tennis balls.
  • Helmets Are Hardly Heroic: Your troops normally don't wear helmets, and they aren't even available without Downloadable Content. It gets especially noticeable when they're wearing Titan armor, which has an isolated filtration system that protects against poison clouds and a built-in cooling system to protect against flames, both of which should require a helmet or at least a mask. The Elite Soldier Pack, Slingshot and Enemy Within DLCs add helmets, but only as cosmetic customization options.
  • Hero Insurance: Your troops can freely blow up anything and everything during an Abduction or Terror mission with no consequences (other than potentially destroying cover you'll need later), and even accidentally killing civilians with poorly-aimed explosives will only net you a minor reduction in the mission rating. Since XCOM represents the only hope of defeating the aliens and protecting humanity, the Council of Nations is not worried about a few hundred thousand dollars worth of damage when the flip side is the possible extinction of the species.
  • Hero Unit: You can give one of your soldiers a specific name to turn them into a powerful XCOM Hero, though this will lock out achievements for that playthrough. All Heroes have 20 Health and 100 Aim and Will, unless stated otherwise below.
    • Sid Meier "Godfather": A Psionic Support Colonel with 200 Will and all Psionic powers available to human units, even the "Rift".
    • Ken Levine "Big Daddy": A Sniper Colonel with 200 Aim.
    • Joe Kelly "Archangel": A Heavy Colonel.
    • Otto Zander "Unbreakable": An Assault Colonel with 100 Health.
    • Chris Kluwe "Loate": A PC only Sniper Colonel. *
    • William Carter "Old Timer": An Assault Colonel added in Enemy Within with a fedora and only 80 Will.
    • On non "Cheat code" side, are the special characters added in via the Operation Slingshot DLC, and Enemy Within, which while not as brokenly OP as the above, are still a cut above the regular recruit, and won't disable achievements.
      • From Operation Slingshot, there's Shaojie "Chilong" Zhangnote , after successfully escorting him as part of his special Council mission back to XCOM. He always starts off as Lieutenant rank Heavy with 9 HP, 75 Aim and 70 Will. At Colonel he has 11 HP, 80 Aim, and either 88 or 106 Will (depending on if the player has the Officer Training School passive "Iron Will" unlocked or not)note . These factors make Zhang not only the best "regular" Heavy in the game under normal circumstances, but also a prime candidate to test him to see if he becomes a Psionic, or in Enemy Within, a MEC soldier.
      • Annette Durand from Enemy Within's Operation Progeny missions will always start off as a Sergeant-rank of a randomly selected class. Her HP is the same as everyone, her Aim score however, is a bit poorer than every class but the Heavy or a MEC trooper of the same rank (and just barely). What she does have however, is a starting Will score of 80, with a maximum potential of 128 Will at Colonel, and is always guaranteed to successfully test for Psionic powers. Needless to say, she becomes a prime candidate to make use of the more difficult powers, like Mind Control.
      • The Furies which can be rescued as part of Operation Progeny, are similar to Annette. Except they all start at Lieutenant with pre-set classesnote , good will scores in the low 70's, and guaranteed Psionic gift.
  • Heroic Sacrifice:
    • The Volunteer during the ending cinematic, stopping the Temple Ship from exploding into a black hole and moving away from the Earth to explode a bit less spectacularly.
    • It will be a certain occurrence if any of your troops are being mind controlled when the final boss goes down, as its death will kill all units considered by the game AI as enemies. As well, troops close by the Uber Ethereal will be killed from it exploding as it dies.
  • He Who Fights Monsters: Dr. Shen wonders if using the aliens' technology, which turned living beings into living weapons and tools, might not cause humanity to go down the same path. Even more pronounced in Enemy Within, where Meld allows the technology to be applied directly to no-longer-fully-human soldiers. However, in Enemy Within Shen is more open to using alien technology to alter humans – his original voice line, expressing horror at the mutilation of the Floaters, is changed to one that expresses disquiet but doesn't rule out the creation of MEC cyborgs.
  • Hidden in Plain Sight: EXALT Headquarters turns out to be located in a fancy skyscraper penthouse. Every Council Nation has at least several of those.
  • Hiss Before Fleeing: Most of the time you stumble upon or are stumbled upon by a group of aliens, they have a mini-cutscene where they all turn around and look at you, growl, then they get a free turn to run to cover.
  • Hive Mind: The Ethereal Collective.
  • Hoist by His Own Petard:
    • Mutons have an ability called "Intimidate" which they use after being wounded to try to get your soldiers to panic, which will have them act randomly by moving, shooting or hunkering down and ending their turn while making them immobile and inactive for the next turn. On rare and deeply ironic occasions, "Intimidate" will cause a soldier whose already acted for the turn to panic and shoot the Muton who just used "Intimidate" dead.
    • Berserkers have an ability called "Bloodlust" that makes them take a free move towards the soldier that shot at them every time they are hurt. Since they are melee only fighters, it may look like a good idea, but it ends up doing them much more harm than good. The reason is that they just get a free move, not a free attack, so even if they completely close the distance and reach their attacker they can only stand next to him and do nothing until the next turn. Which they usually never live to see, since they are now standing without cover in the middle of a squad of angry XCOM soldiers who will slaughter them at short range. It is even worse if you have the perk that grants your Assault soldiers a free reaction shot against any enemy that moves within 4 squares: two such Assault soldiers close enough to each other will brutalize a trapped Berserker.
    • When an enemy psionically attacks a soldier with the Neural Feedback gene mod, the attacker suffers massive damage and gets all their psionic abilities put on forced cooldown. Not even the mighty Ethereals can defend against this passive ability. The feedback damage is enough to One-Hit Kill basic Sectoids and grievously wound more powerful enemy types. Best of all, a successfully mind-controlled XCOM soldier with this mod can actually save themselves if the feedback pulse manages to kill the attackernote , thus ending the mind control before it can do any harm.
    • The entire point of the game, really. Aliens attack Earth with vast technological superiority, and Earth fights back by taking that technology and improving on it. The Firestorm interceptor is more powerful than anything short of the Temple Ship, and aliens never field Alloy Cannons or Plasma Sniper Rifles because those are completely custom XCOM designs.
  • Hold the Line: Two variant mission types in Enemy Within:
    • One of the EXALT mission types, Covert Data Recovery, involves protecting a transmitter that is feeding XCOM intel on their operations. You have to defend an encoder, which is hiding the location of the transmitter, and if the encoder is disabled by EXALT, you have to defend the transmitter itself; you do that in traditional King Of The Hill fashion, by staying within a certain distance of the encoder/transmitter to block EXALT from "capturing" the equipment (i.e. being the only ones within the perimeter for a certain number of turns). Once you've killed all the EXALT waves, the mission is successful; if EXALT hacks both the encoder and the transmitter, or the transmitter is destroyed by any cover-destroying damage, the mission fails. If you manage to protect the transmitter and the encoder, the mission reward is more generous.
    • The other variant is Operations: Ashes and Temples, where you defend the Delta section of XCOM's headquarters against multiple waves of alien invaders some time after you destroy the alien base. There are four waves of enemies and you start with your three highest units on the soldier's list, with more coming as reinforcements, and there are also Base Defense troops (essentially slightly worse rookies that always have frag grenades) to assist your squad.
    • Furthermore, the entire game is basically an example of "hold the line", as the player is required to fend off endless waves of alien assaults until they can find and assault the alien command ship. This is particularly true early on, as the player is in a desperate struggle to keep the panic rating of council nations low and handle the constant alien abduction missions until they are all under satellite coverage.
  • Hologram Projection Imperfection: The aliens use plenty of holographic interfaces for the computers on their ships and bases. This becomes more obvious when a character shoots through them, the holograms "shatter" and break apart, only to reform again after the air above them clears.
  • Homing Boulders: All hits and misses are determined by the RNG first and foremost, and weapons fire can count as missing even when it visually hits the target. If it's a miss, it's a miss, no matter where the in-game representation of the shots land; even if an entire burst hits the head, chest and belly of the target's model, if it's a miss, no damage is dealt. Because the game rolled "failed" or if it's suppression (which doesn't do damage unless Mayhem, a Colonel rank Heavy-specific skill is chosen), the representation just generates fire in a random cone, which means even missed shots could drill the target right between their eyes. Of course, those shots don't do any damage, even if your barrage of suppressive fire hits that Muton in the face, and vice-versa.
  • How Dare You Die on Me!: One of the upgrades from the Officer Training School is "Don't Die On Me", which increases the chances that soldiers will simply be critically wounded when their HP drops to 0. The chances go up as they become higher ranked. No longer present in Enemy Within, since there are gene mods that do the same thing, only better (the critical injury is guaranteed to preclude immediate death instead of being a chance of happening, and there's no Will penalty).
  • Human Resources:
    • The aliens are kidnapping humans for their own mysterious purposes, but you can turn this around on them. Many items you can create through Engineering or the Foundry require you to use up the bodies of aliens (you're ripping out their cybernetic implants or other useful material).
    • After taking out the first Alien Base, you get a number of "Alien Food" canisters in your "Grey Market" inventory. They have no research function and can be sold freely, but the description indicates the slurry within has DNA markers consistent with humans.
  • Humans Are Special: Turns out humans share the right combination of physical toughness and psionic potential, and the aliens want to make that specialness part of their empire.
  • Hybrid-Overkill Avoidance: MEC Troopers in Enemy Within can't receive gene mods or take the Psionic test. Gene-modded soldiers, if augmented into MEC Troopers, lose all their gene mods, and psionic-gifted soldiers can't be augmented at all. In addition to that, if you're running with the "Mind Hates Matter" Second Wave option, gene-modded soldiers can't be tested for psionics and psionics can't undergo genetic modding.
  • Hyper-Awareness: The "Bioelectric Skin" genemod amplifies the soldier's latent electrical field so they can sense enemies close by, even if they have no line of sight. Useful for sensing if there's a group of enemies in the next room or finding cloaked Seekers.
  • Hypocritical Humor: There's a couple examples.
    • A captured EXALT soldier deprived of his Cyanide Syringe states that "XCOM is nothing but puppets..." He is, however, part of an organization that is trying to help the aliens conquer Earth because of the potential benefits of siding with them. Ironically, however, he's right about XCOM, since XCOM is unwittingly part of the Ethereals' uplifting agenda.
    • A particular line by Dr. Shen upon seeing the "Alien Entertainment" module for the first time during the base assault is strikingly hypocritical, but in a hilarious way. Also doubles as a Take That! to the player.
      Shen: Is this what the aliens do for fun? At least they're not playing... computer games.

    I-L 
  • I Can Still Fight!: Unfortunately Averted. Given the desperate situation XCOM finds itself in, you'd think they'd let an injured soldier back into the fight if there's a shortage of manpower and they aren't going to collapse the moment they step out of the Skyranger. However, soldiers cannot be released from the sickbay early, even if they lost only 1 health the previous mission and only have a few hours of bedrest remaining. Painful especially when it means you have to do that Terror mission with Squaddies while your Colonels twiddle their thumbs.
    • The only exception to this is the XCOM Base Defense mission in Enemy Within, where injured soldiers will be used with chunks missing from their HP.
  • I Did What I Had to Do: The Ethereals say this in response to something coming. They are not repentant about it, however: they did what they had to do because they could.
  • Idiosyncratic Difficulty Levels: The difficulty levels are called "Easy", "Normal", "Classic"* and above that, "Impossible", with "Classic" being meant to be the closest to the original game's difficulty (that could be achieved with the game mechanics of the 2012 remake) and "Impossible" even more difficult than that. There is also another difficulty modifier called "Ironman Mode", where the game will only have one save file for that playthrough, and will save for the player after every action during combat, meaning that if you make a mistake there is no reloading to before it happened. Now try that on Classic difficulty...
    Some designers also mentioned that the "Impossible" difficulty is literally supposed to be Unwinnable by Design. For most players, it's just a question of how many missions they can complete before failure. According to the staff, beating Impossible difficulty on Ironman mode is only theoretically possible. Some players have managed to pull it off, though, and as if in retaliation, Firaxis released the Second Wave Downloadable Content, which includes gameplay modifiers even they thought were too cruel. This was taken further again in Enemy Within, with both Classic and Impossible difficulties getting a significant spike in toughness.
    When a Let's Player not only finished the game on Impossible Ironman, but did it without losing a single soldier, it was reported on various gaming news websites.
  • The Illuminati:
    • Averted with XCOM. Despite being ruled by an The Omniscient Council of Vagueness, they are not an example of this.
    • In Enemy Within, Played Straight by EXALT. They're a secret society of paramilitary operatives working in the shadows and masquerading as ordinary citizens. Each one of them is fanatically loyal to the cause and won't stop at anything to take the aliens' gifts and Take Over the World. The organization is also shown to be very old and very wealthy, their base having a lot of fancy decorations and priceless art. Their insignia even has the stereotypical Illuminati "eye"!
  • Imagine Spot: How the applications of Meld are explained in Enemy Within. Each scientist describes the potential applications, while cuts of MEC suits and gene-augmented soldiers in action are played.
  • Imperial Stormtrooper Marksmanship Academy:
    • Averted, in stark contrast to the preceding titles' notorious reputation. Soldiers always shoot in the right direction and have a decent to-hit chance as long as they're within a reasonable range for the weapon they're holding. Most tellingly, grenades always go where they're supposed to. It makes you feel like you really are commanding the elite troopers that the original game claimed you were.
    • Zig-Zagged for Heavies, who have a chance of missing with regular rocket launchers: instead of the missile veering off-course after being fired, they blatantly aim off-target and shout "Missile wide!" before even firing. However, they put the missiles exactly where they are supposed to go nine times out of ten; it's just really obvious on those rare occasions that they miss. One of their miss quotes for the rocket launcher implies an equipment failure, though ("Targeting system malfunctioning!"), which may explain how they know the missile will stray off course before even firing. In general, the class' Aim stat is noticeably lower than the other classes.
    • Also played straight if your soldier is hit with Debuffs like "Mindfray" or being poisoned, especially if they're a rookie. Nothing like a soldier missing an enemy three meters away and being perforated the next turn.
    • Weaponized in gameplay mechanics; combatants that don't use cover receive permanent cover bonuses instead, so a Sectopod can stand in the open and watch as your entire squad fails to hit a car-sized target at less than 50 feet. Presumably their hands are shaking with terror at said car-sized target.
    • Exaggerated in Enemy Within. When a soldier misses a shot, they start by blatantly aiming their weapon several degrees off of their target, fire every projectile to the exact same spot, and only then report that they "missed".
  • Improbable Aiming Skills:
    • If a Sniper has the right perk and nothing blocking their shot, it's completely possible to snipe an enemy from across the map, provided an ally can see them. The sniper rifle weapon even gains accuracy farther away from targets to aid thisnote .
    • Thin Men on Classic and Impossible difficulty. They have a base 75 Aim and 10 Crit with another 10 of each added due to their light plasma rifles. Combine this with being the second enemy you will likely see in a game makes them infamously difficult to fight and very likely the main source of your Memorial Wall entries.
  • In a Single Bound:
    • Thin Men are able to hop right up to the tops of buildings to gain instant height advantage and the Aim bonus that comes with it. Yet another reason they are so nasty despite being physically frail.
    • Even worse, the Chryssalids can do it too.
    • Thanks to the Bio-Augmentation system added in Enemy Within, your soldiers can be augmented to do the same. For bonus points, the gene mod that allows it, "Muscle Fiber Density", is unlocked after autopsying a Thin Man.
    • With the "Jetboot Module" Lieutenant-rank skill, even MEC troopers can get in on the fun. It has a 1-turn cooldown after activation, however.
  • I Need You Stronger: On a species-wide scale. The true purpose of the invasion is to test whether humans have the right combo of physical and psionic strength desired by the Ethereals, which is why the aliens gradually scale up the forces they're sending instead of curbstomping Earth with everything at once. Assuming you win, it works too well. XCOM 2, however, decides not to go with this and have the aliens curbstomping Earth with everything at once, in order to subjugate humans and use them for their Avatar Project.
  • Infinity +1 Sword: Quite a few. Many of them can cross over into Bragging Rights Reward as well.
    • The Fusion Lance, able to down even Battleships in a couple of shots.
    • The Blaster Launcher is incredibly powerful and probably the best example in terms of weapons held by humans. Not only do you get a base damage boost to rocket blasts, but shots can also be automatically guided to their target, meaning the Heavy wielding it doesn't even need to expose themselves to get line-of-sight as with the standard launcher. However, even building one of them has a hefty resource cost, as each requires two flight computers and a fusion core, the latter only available from late game battleships, apart from two potential freebies from the Slingshot DLC's council missions.
    • The third tier of weapons, plasma, are the best you can get, and even includes weapons the aliens themselves don't have, like the Plasma Sniper and the Alloy Cannon. The Alloy Cannon in particular is the most damaging soldier weapon in the game, even more so if it gets a critical hit, outclassing the Heavy Plasma and even the Sectopod's chest cannon and plasma turret. Rapid Fire with it, if both shots manage to hit, will tear a nice and large hole into anything in the game.
  • Instant-Win Condition:
    • The last mission. The second you defeat the Uber-Ethereal, you win the game.
    • You don't have to rescue all the civilians on Terror missions; if you just kill all the aliens, it still counts as a victory. Some people will just save one civvy, then let the aliens come to them, in order to avoid losing soldiers for no great benefitnote .
  • Interface Spoiler:
    • Even if you don't have line-of-sight to an area and thus wouldn't know where the enemies are (or the enemy in question is cloaked), you cannot make a move order into a square that contains an enemy. This is visible on the map.
    • The cinematic camera often spoils the outcome of direct attacks; while "Overwatch" and grenade attacks usually provide a cinematic cut regardless, a standard attack only ever does so if the hit is going to both connect and kill the enemy in the next few seconds, though kills can occasionally happen without the cinematic camera triggering (much more often in Enemy Within). This happens to the aliens on their shots as well, so if a firing alien gets a camera shot panning over them, the next camera shot will be of one of your troops getting killed or critically wounded.
      • Strangely enough, the game can subvert this. When using an Arc Thrower, the cinematic shot may engage, but the shock fails to incapacitate the target as it usually occurs.
      • Downplayed in Enemy Within: the cinematic camera activating is no longer a guarantee of a hit. Similarly, not seeing the cinematic camera activate doesn't mean you'll miss. The game seems to determine when a particular shot is appropriately dramatic (i.e. could turn the battle around if it's a hit or a miss) and uses the camera for those.
    • The achievements for upcoming Downloadable Content are uploaded to the list of global achievements on Steam before the content is released. They can easily be picked out by being listed as 0.1% other players getting them (aside from the usual Nintendo Hard ones) and don't show up on the standalone list, and can spoil the presence of certain missions and/or enemies.
    • Sectopods can launch missile barrages, but it takes them to charge for a turn to do so. When this happens, the camera centers on the machine, and then on the area it's about to bombard. The spoiler comes in the fact that the camera still moves in this fashion even when the Sectopod is outside visual range, so if you see this camera motion even if no Death-Machine is in sight, get the hell out of there.
    • Minor one, but after completing Slingshot and researching the Fusion Lance, the game will say it's meant for the Firestorm even if the Firestorm hasn't been theorized yet.
    • Meld is referred to by name by the game labels even before it is officially dubbed as such.
    • Oddly Subverted in Enemy Within. When using Rapid Fire, if the first shot misses, there will be two "shot missed" indicators over the target, implying the next shot will be a miss as well... but then the next shot could still kill your target dead.
  • Interservice Rivalry: Downplayed, but Vahlen and Shen make it clear that they disagree on how best to utilize Meld, preferring bio-augmentation and cybernetic enhancements, respectively.
    • Lampshaded by Bradford: "Is there anything you agree on?" They hesitate, then announce that they agreed on the name*.
  • Invisibility Cloak:
    • The Overseer UFO is protected by one of these, requiring the use of the Hyperwave Relay to find it.
    • Ghost Armor lets your troopers sneak around on the battlefield.
    • XCOM can use Ghost Grenades to cloak several units at once in Enemy Within.
    • Alien Seekers in Enemy Within can cloak as well. Researching their corpses allows you to add the "Mimetic Skin" gene mod to your troopers, so that they can do it too.
  • It Only Works Once: When the aliens directly attack XCOM HQ in Enemy Within, they explicit only try it once. Vahlen posits that they used too much power trying to mind control half the base personnel, which is why they don't try it again. Completing Operation Progeny reveals that she is correct.
  • It's the Only Way to Be Sure: A unique Council mission in Enemy Within called "Site Recon" has you investigate "unusual activity" in a fishing village in Newfoundland, Canada. When it turns out that the "unusual activity" is a hive of Chryssalids using a whale and sharks as incubators for more Chryssalids, Bradford decides to call in an airstrike to wipe the place off the map.
  • Item Crafting: Most of the stuff you can research or manufacture requires you to expend more than just credits, but also various resources or items you've collected from the aliens. Alien Alloys and Elerium are the two big ones, but you also need to use up Weapon Fragmentsnote  and the dead bodies of aliensnote  for a lot of products.
  • I Want Them Alive!: Used in spirit, if not actually said outright. Several objectives in the game require that aliens be taken captive rather than killed, which presents its own set of challenges since the team must take care to soften a target up without killing it, then getting into range to use an Arc Thrower. However, the player may find themselves wanting to do this more often than is absolutely required, since it allows them to recover the enemy equipment intact, which is much less resource intensive than building their own. The only aliens that are required to complete the game are a Sectoid (or a Thin Man) and an Outsider.
    • Live interrogations of aliens do not directly unlock new technology, but they cut research time in half for whole groups of technology topics; combine that with South America's "We Have Ways" for instant interrogations and you can cut months of research project time off if you regularly capture every new type of alien alive.
  • Jack of All Stats: The Support class has pretty average stats all-around, as do the assault rifles they wield.
  • Jetpack: Built into the Archangel Armor, allowing your soldiers to take to the skies. Floaters look like they're wearing them, but it's actually built into their bodies. MEC suits can be retrofitted with jet boots.
  • Jitter Cam: The camera shakes slightly during cinematic shots when your soldier bashes through a door or jumps through a window, and it's mostly noticeable when the shaking persists until your turn finishes.
  • Just Plane Wrong: In the Tutorial mission, a scanner identifies a downed German helicopter as a NH90note , while displaying a schematic of a UH-60 Blackhawk.
  • Keystone Army: Subverted the first time and played straight the second time. Bradford thinks the aliens are done after you destroy their base... which quickly turns out to be an outpost of the main force. The Temple Ship's destruction does cripple the aliens, but given how its destruction involves the deaths of most of the aliens' command staff and their leader, as well as how they were using it to supply their ships, that makes perfect sense.
  • Kill It with Fire: Fire is simply a barrier to non-Titan armored troops in Enemy Unknown, unless it spreads into the square they're standing in. Enemy Within, on the other hand, introduces MEC-mounted flamethrowers, as well as an incendiary bombing run in the ending cutscene of a certain Council mission. Amusingly, MEC troopers sometimes actually say "Killing it with fire" when using their flamethrowers.
  • Kinetic Weapons Are Just Better: Played With. While XCOM's ballistic weaponry is more sophisticated than our own, it's still woefully outclassed by laser and plasma weaponry. Upgrading to better weapons is a must once you get past Thin Men and Floaters. On the other hand, the Alloy Cannon, essentially a shotgun that fires rounds made of alien alloys instead of more conventional materials, is better in close quarters than almost any other weapon.
  • Kung Fu-Proof Mook: Chryssalids, Cyberdiscs and Sectopods are immune to Stunning, as well as Seekers and Mechtoids in Enemy Within. In addition, some enemies have the Hardened property, which drastically reduces the likelihood of a Critical Hit; more often than not, the reduction is big enough that you'll get a fat 0% chance to crit.
  • Late-Arrival Spoiler: Before the game's release, combing through the numerous preview videos and the demo revealed a lot of information ostensibly kept secret, such as (seemingly) the full roster of aliens, plot-important videos and details about autopsied alien invaders. If not careful, it's very easy to spoil yourself without trying. Given that this is a remake of a much earlier game, there was little expectation that these things would stay unknown to most players from the start.
  • The Law of Diminishing Defensive Effort: It's a game mechanic here. Units that can't Take Cover!, like Sectopods and Berserkers, receive the "Hardened" ability and a huge base defense rating. This can allow them to stand out in the open and have a lower chance of being hit than enemies in cover twice the distance away.
  • Leaning on the Fourth Wall/Take That, Audience!: The peanut gallery regarding the alien entertainment device you find during the assault on the alien base:
    Dr. Shen: "Is this what the aliens do for fun? At least they're not playing ... computer games."
    • When searching for the EXALT base, one possible clue is: "The EXALT base is in a country you can play as in Civilization V."
    • Similar example: when staying in the Situation Room long enough, one of Bradford's possible lines is:
      Officer Bradford: "Are you really using our tracking terminal to play Civilization?! I at least hope you're going for a Military victory."
    • In Enemy Within, a possible line from a MEC trooper after getting a kill goes as follows:
      MEC Trooper: "Hostile removed from play."
  • Leeroy Jenkins: At first, the Assault's "Run & Gun" ability can seem like this... but pair it with their "Lightning Reflexes" ability, and suddenly they're sprinting up and triggering that alien's Overwatch to waste it, clearing the way for your squishier troops to come up and push through. You can invoke this as well. Got a dark room where you know aliens are? Send in a rookie trooper, with a Heavy standing by with a rocket. Cleanup on aisle seven!
  • LEGO Genetics: Hand Waved with Meld, a substance that can bond and remove genetic material. Subverted with EXALT since they don't have access to Meld and their genetic modifications are crude and make their operatives look very sick.
  • Lensman Arms Race:
    • Between XCOM and the aliens. At the beginning of the game, XCOM has ballistic weapons, mostly ineffective armor, and little else, while the aliens field the much weaker Sectoids and Thin Men, armed with plasma pistols and light plasma rifles at worst. By the time XCOM has started to field advanced equipment in the form of laser weapons and armor forged from the alien alloys, the aliens up the ante with Mutons and Floaters, some armed with full-sized Plasma Rifles. When XCOM finally gets to highly advanced equipment like plasma weapons of their own, incredibly advanced armor and psionics, the aliens are fielding Elite Mutons, Heavy Floaters, Sectopods, and Heavy Plasma cannons.
    • This also takes place between XCOM and EXALT in Enemy Within, as both sides gradually advance from ballistics to more advanced weaponry. EXALT also gains the ability to gene modify their operatives, just like XCOM. They don't get a MEC equivalent and can't advance past laser weaponry, but they do have their own unique gene mods that are beyond XCOM's ethical limits and more effective as a result.
  • Lethal Joke Character:
    • South America's "We Have Ways" bonus is kind of laughable in regular gameplay, because once you get plenty of scientists you'll be completing autopsies and interrogations in a single day. But turn on the "Marathon" option in Second Wave, and suddenly South America's bonus becomes critical, because all research times are increased several times over, and you can't afford to waste most of a month on autopsies and interrogations. Not to mention that the research credits from interrogations greatly reduce the lengthy research times on advanced technology, which is the difference between spending an entire month unlocking a new technology and only a dozen days working on it. Doubly so when starting in South America (even though the continent otherwise requires only two satellites), making a hell of a difference in the early game.
    • As for characters, the base security personnel in Enemy Within are expected to be nothing more than RedShirts. However, with the "Tactical Rigging" Foundry upgrade, they'll all have two grenades at their disposal, meaning the large squad size (up to eight compared to the usual maximum of six) and extra grenades can actually be quite the benefit.
  • Levels Take Flight: The Battleship at the end of the Slingshot DLC and the Temple Ship involve you attacking them while they're still mid-flight. Despite being able to see the Earth sprawling below you, you're not at risk of falling.
  • Lightning Bruiser:
    • The Assault class is the only class that can dash/move twice and still shoot before the enemy has their turn, complete with numerous perks that significantly increase either their damage output or durability. They even get bonus hitpoints for wearing heavier armor, on top of having the best base health progression.
    • MEC Troopers have guns that hit even harder than a Heavy's and have a massive health pool due to their suits, as well as a number of skills/upgrades that reduce damage. They are also pretty quick on their feet if they're equipped with a MEC suit built with the "Kinetic Strike Module" Tactical Subsystem, which bestows a +3 bonus to mobility. The "Advanced Servomotors" Foundry Project pushes this even further, giving them a passive +3 Mobilitynote  that is reflected by their movement animations: while by default MECs jog to their new positions, after the upgrade they switch to big loping steps that are noticeably faster.
  • Limited Loadout: Every one of your troops gets a primary weapon (the type of which is determined by their class), a secondary weapon (a pistol unless they're a Heavy, in which case they get a rocket launcher instead) and a slot for extra utility items like Medikits or the Arc Thrower. Supports can unlock an extra utility slot once they reach Major prior to Enemy Within, which instead has a Foundry project called "Tactical Rigging" that affects all classes but MEC Troopers, who never get any inventory slots.
  • Load-Bearing Boss: Killing the Uber-Ethereal in the final mission causes the Temple Ship to begin self-destructing from the resulting release of psionic energy and the damage caused by the alien orb going out of control, necessitating the Volunteer's Heroic Sacrifice to prevent it from taking the Earth with it.
  • Lock-and-Load Montage: The introduction cutscene features this.

    M-P 
  • MacGuffin Delivery Service: How the aliens view the attack with your best psionic soldier on their Temple Ship. But since they still shoot on sight and never bother with any plan to get that soldier to join them, you will probably make them regret it. Alternatively: The Aliens wanted your best to be on that ship. Why? Its a test. Everything has been a test. This is the last to see if humanity has what it takes. To do what is left ambiguous.
  • Made of Iron:
    • One of the high-rank Assault's tricks. They automatically gain "Extra Conditioning" once they reach Major, which confers additional health depending on the armour they're loaded withlist. Give them Titan Armor and Chitin Plating, and they can soak up more damage than a Cyberdisks or Berserker on lower difficulties, and match a MEC-3 Paladin on Classic and Impossible. Upon reaching the Colonel rank, they have the option to get "Resilience", which makes them immune to Critical Hits.
    • Heavies have the "Will To Survive" passive ability once they reach Major, which reduces all damage they take by 2 points while in any kind of cover, as long as they're not flanked.
    • EXALT's Elite Heavies have the "Iron Skin" gene mod, which reduces all incoming damage by 25%. Good thing they only have 10 health.
    • Sectopods in Enemy Within, thanks to the new "Reinforced Armor" passive ability that halves all incoming damage save for Electro Pulse.
    • MEC troopers in Enemy Within can soak absurd amounts of damage if the right perks are chosen. An Assault made into a Mec gets Shock-Absorbent Armor (33% damage reduction from any attack made within 4 tiles, including grenades). Combine this with the Sergeant-rank ability "Damage Control" (-2 damage taken on any attack for 2 turns after being attacked), the Captain-rank ability "Repair Servos" (heals 2 HP per turn, up to 6 total per mission), and finally the Colonel-rank "Absorption Fields" (cannot take more than 33% of their max health in one attack), and you have a unit that can be attacked by three Berserkers at once and still have a little over a third of their health left.
  • Mad Scientist: Downplayed: Dr. Vahlen, the head of Research, is definitely a lot more gung-ho about SCIENCE! than Dr. Shen, though she does persist on personally overseeing any interrogation attempts.
  • Majorly Awesome: Any soldier who makes it to Major, the second highest rank available, is certainly awesome.
  • Mass Hypnosis: In Enemy Within, the aliens forcibly mind control quite a few XCOM personnel into sabotaging internal security as the precursor to their assault on XCOM HQ. Bradford is forced to beat the crap out of a mind-controlled XCOM technician trying to assassinate him.
  • Mauve Shirt: Any Squaddie (any operative with a couple of missions or a kill under their belt, at least until you get the upgrade that gives the rank for free) is one. The customization of the troops grinds it in.
    • Moreso when they reach Sergeant, which is when your battle-hardened troopers earn themselves a custom, randomly-generated nickname (that you can then customize yourself, if you wish).
    • Even the highest ranking of your soldiers can qualify as Mauve Shirts. All it takes is a couple of well placed shots, a single Chryssalid or Muton Berserker, or an Ethereal mind controlling one of your finest soldiers into shooting their buddies and even your most trusted and powerful soldiers can die. Made worse on Ironman mode, wherein you can't reload your saves and those guys are gone for good.
  • Meaningful Name: The Slingshot DLC mission pack is so named because it throws you into tougher-than-normal missions with substantial rewards that allow you to research and build way more than you normally would be able to. Thus a little extra effort allows you to "slingshot" up the tech tree.
    • Extends to Enemy Within, as well. The primary new mechanics added by the expansion are gene and cybernetic mods, plus the addition of EXALT. Gene and cybernetic mods are derived from alien tech, literally putting enemy technology within our own soldiers. EXALT is a human faction confounding XCOM's efforts—an enemy within humanity. There's even a new mission added that has mind-controlled soldiers allowing the aliens to assault XCOM's base, yet another enemy within.
  • Mecha-Mooks: Played with: the Drones are definitely these. They are numerous and die in one hit, but have the ability to repair their bigger brethren. The Cyberdiscs and Sectopods, however, are vastly more dangerous, as they are bristling with firepower and very heavily armored.
    • Seekers are squid-like robots with a built-in plasma pistol and cloaking device, and a six-pack of Combat Tentacles they use to strangle unlucky soldiers with.
    • On the players side, SHIV unmanned tanks can take the place of a Heavy trooper.
  • Megaton Punch: MECs with the Kinetic Strike Module can punch enemies in an adjacent tile hard enough to catapult them into nearby obstacles, and if that obstacle happens to be a car, it'll explode instantly. Dealing 18 points of guaranteed, unavoidable damage when fully upgraded, this is one of the most powerful and reliable attacks in XCOM's arsenal, one that few enemies can survive, and the ones that do won't survive the rest of Strike One's attention.
  • The Men in Black:
    • The Thin Men, directly drawn from the eponymous rumors started in the 1950s about mysterious agents covering up UFO sightings. They're humanoid infiltrators with extreme agility and the ability to spray poison from a distance. It's strongly implied in the autopsy report that they are in fact genetically-altered Snakemen, or at least reptilian in origin.
    • The Council representative is also a mysterious MIB, though at least he's on your side.
    • XCOM is technically composed of MIBs, though obviously much more militant and less concerned with remaining secret.
    • EXALT troops look more like traditional MIBs, especially with their suits.
  • Mighty Glacier:
    • The Heavy class packs some of the most powerful infantry weapons available to XCOM. However, they only have average movement speed and range, cannot fire their rocket launcher after doing nearly anything, and need to forego their movement in order to take advantage of Bullet Swarm and fire twice in a turn.
    • On the Alien's side is the Sectopod. Like the Heavy, it can move a limited distance, but it favors standing still due to being able to fire twice in a single turn (which sets it up for a free overwatch as well).
    • MEC troopers in Enemy Within are bigger and stronger than regular soldiers (and most aliens), but until you upgrade their leg servos they have similar limitations to the Heavy.
    • A high-level, properly-specced Sniper is quite possibly the deadliest force on the battlefield, but can't move and fire their sniper rifle in the same turn without taking the Snap Shot perk, which deprives them of another very useful perk.
  • Mile-Long Ship:
    • The alien battleships are enormous – during raids on crashed battleships, their upper decks alone take up the whole map. A cutscene in the Operation Slingshot DLC shows a battleship hovering over a city, dwarfing the skyscrapers.
    • The Temple Ship is even bigger – its emergence over the Atlantic Ocean causes worldwide earthquakes, and in the final mission, its self-destruct sequence threatens the entire planet.
  • Mind Rape: The psionic aliens have the full range of fun little tricks from the original, as well as new ones. Unfortunately for them, two can play at that game. Which is exactly what the Ethereals want...
  • Mini-Mecha:
    • The aliens have the Sectopod in the base game, joined by the brand new Mechtoid in Enemy Within.
    • XCOM gets the Mechanized Exoskeletal Cybersuits in Enemy Within, which require their operators to be Cyborgs.
  • Mirroring Factions: The Ethereals to humans. As it turns out, the Ethereals have been experimenting on other species, modifying them genetically and mechanically in hopes for them to be able to obtain the Gift but none of them succeed.
  • Modular Difficulty: The game and its expansion Enemy Within feature a variety of options in addition to the difficulty levels, including "Ironman Mode" (prevents save scumming), and the "Second Wave" options, which range from giving rookies highly variable stats to randomizing damage and funding. These options are unlocked based on the difficulty levels of campaigns you've completed previously.
  • Money for Nothing: Once you manage to get satellites over the majority of the funding nations, you will be rolling in Credits. The bottleneck then becomes Alien Alloys, Elerium and Weapon Fragments, all of which need to be taken from the aliens.
  • Monty Haul:
    • Completing the Slingshot Downloadable Content nets you an intact alien battleship possibly less than two months into the game, which yields a tremendous amount of alloys and Elerium, plus an earlier route to endgame weapons. Chances are, you'll have to try extra hard to even come close to running out of resources again. On the other hand, you'll be facing said Battleship's guards, albeit toned down. Fighting Mutons and Chryssalids with only Ballistic or Laser weapons, Kevlar or Alloy armor, and a small team of somewhat inexperienced troops can make it all into a sequence of Brutal Bonus Levels, even on easier difficulties, though still worth the huge payout. However, the real prize besides the Fusion cores is not the Elerium and Alloys... it's the corpses and interrogations. If you stun the Muton and capture him, then destroy the Drone, Cyberdisk, and Chryssalid without blowing them up, you can shave literally months off of the research and Foundry trees.
    • Operation Progeny plays it straight for its final mission. You get 3 Lieutenant-ranked soldiers who are guaranteed to be psychic for a mission that was easier than the previous one.
  • Morale Mechanic:
    • Soldiers with low Will scores are more prone to panicking, which can happen if the squad takes casualties or a Muton successfully intimidates them. Panicked soldiers will shoot at a random target (even their own teammates), run to a random and potentially dangerous location or hunker down. Regardless of which effect occurs, they cannot move or act during the next turn unless the debuff is removed with the "Psi-Inspiration" ability. Enemy Within also reduces their Aim while Panicked. However, stories abound of this backfiring; as panicked agents sometimes paste the enemy who frightened them.
    • An Officer Training School ability added in Enemy Within is "Lead By Example", which raises all soldiers' Will scores to that of the squad leader's when they're in close proximity to said leader, while those with higher Will scores aren't affected. It also adds the "Neural Damping" gene mod, that makes the soldier immune to panicking as well as only being stunned by a Mind Control attempt; unfortunately, it's not available for MEC Troopers.
  • More Dakka:
    • LMGs in general, especially when using the Heavy's "Suppression" ability. Assault Rifles in general also spam rounds with the Support's "Rifle Suppression" ability, even if they normally only fire a few rounds when shooting normally. S.H.I.V.s (and MEC Troopers in Enemy Within) also start off with a bullet spewing minigun, and the S.H.I.V. can use it to suppress an enemy.
    • The Assault's "Rapid Fire" ability (activate to fire twice with an accuracy cost), the Support's "Covering Fire" (reaction fire to enemy attacks within their sight in addition to movement) and "Sentinel" passives (fires twice on Overwatch), the Heavy's "Bullet Swarm" passive (can fire twice if they did not move that turn) and the Sniper's "In The Zone" (killing a target out of cover or flanked doesn't cost an action) and "Double Tap" (firing or using firing abilities doesn't end their turn) passives all provide you much potential for additional dakka. Enemy Within also adds the "Overdrive" passive ability for MEC Troopers, allowing them to shoot twice if they don't move, much like "Bullet Swarm".
  • Multi-Armed and Dangerous: Ethereals have four arms now, though unlike other examples, this is probably more for Rule of Cool than anything else, since they attack only with psychic powers and don't even carry a weapon.
  • Multinational Team: Much more diverse than in the original game; you can even get recruits from countries that aren't part of the Council of Nations. It's not at all uncommon to have an entire six-person squad whose members are all from different countries. However, they all share the same pool of American accents, which thankfully is (mostly) rectified with the Enemy Within expansion.
    • In an odd twist, recruits from Scotland and recruits from the rest of the UK are treated as being from different countries, with their own flags and name pools.
    • Encouraged in Enemy Within, as there's a medal type that gives bonuses based off how many different countries are represented in that soldier's squad.
  • Mutual Disadvantage: It is possible to place a soldier in a position which has them flanking an enemy (negating their cover bonus and significantly increasing their chance of scoring a Critical Hit) whilst simultaneously having them be flanked by that enemy. Risky, but sometimes worth it. This is the Assault class' specialty, since their basic "Run & Gun" ability allows them to shoot after moving twice/dashing, allowing them to jump right behind the cover the aliens are in and pumping them full of buckshot/lasers/alloy shards in the same turn before they can act. They can also have the "Lightning Reflexes" ability, which forces the first reaction shot fired at them in a turn to miss.
  • My Rules Are Not Your Rules:
    • Aliens (and EXALT soldiers in Enemy Within) don't panic in the same way as XCOM soldiers unless psychically induced (or set on fire with the MEC Trooper's Flamethrower in Enemy Within). While they tend to withdraw if the rest of their group gets wiped out quickly, they won't lose their next turn or fire a panicked shot at a random target.
    • Robots are immune to psi-powers, so it's good tactics to send your S.H.I.V.s against psi-users. However, Ethereals can use their unique "Psionic Lance" and "Rift" psychic powers, which do increased damage the lower the target's Will is. Since robots have 0 Will, these psychic abilities can one-hit kill any of your S.H.I.V.s.
    • Aliens get to move out-of-turn upon being discovered, usually to take cover. XCOM's Red Shirts don't get to do so. However, they will also move without attacking if they discover you on their turn, so your soldiers won't get instantly wiped out if they're surprised.
  • Mysterious Waif: "Portent", an optional subplot of Enemy Within follows Annette Durand, an unusual, psionically gifted individual with a mysterious past. The aliens considered her such a threat that they were willing to strafe a dam while the truck carrying her was crossing it, and then send ground troops onto the stricken structure to keep XCOM from rescuing her. EXALT is just as That's because she was used as an Amplifier Artifact that enabled the aliens to Mind Control XCOM's personnel inside their own base in an attempt to destroy XCOM.
  • Mythology Gag: With a side of Genius Bonus.
    • The Council of Nations is represented by a bald man wearing a suit sitting in the shadows. In the original game, the Funding screen and the end-of-month summary was displayed on a background with a very similar man holding a briefcase full of money.
    • The pre-order bonus and the Elite Soldier Pack includes a blonde dude with a humongous flat-top, as well as a TF2 Hat depicting the same hairstyle. In the original game, the sprites for male X-COM soldier had this same haircut, and this was one of the four available in-game art for male soldiers.
    • The basic weapon for Interceptors are Avalanche Missiles, which were the best terrestrial interceptor weapons available in the original game.
    • Manufacturing your first laser or plasma rifle has a cutscene where it's used on cardboard cutouts of the original Sectoid (for laser) and Muton (for plasma).
    • The Thin Men are very strongly implied to be genetically-altered Snakemen. Even better, the original game implied that the Snakemen had a very dangerous and deadly poison, though it never made it into the game. One of the Thin Men's most dangerous attacks is hitting you with a cloud of deadly poison.
    • The Floater Autopsy report is codenamed "Crimson Cape", a reference to these aliens' appearance in the original.
    • The final mission is always named "Operation Avenger". In UFO Defense, the Avenger was the transport ship X-Com had to build to reach the final mission on Mars.
    • The Elerium research project is codenamed "Project E-115", a reference to the original game where Elerium was referred to as the 115th element on the periodic table*.
    • The short musical cue that plays when a round of psi training is completed is from the original's Geoscape theme.
    • The Achievement for building your first Firestorm is called "Ride the Lightning", which might refer to the much-maligned aircraft of the same name from the original.
    • Muton Elites and Berserkers are red, just like "Mr. Angry Red Suit" who was never fought in the original.
    • An arcade machine in the base's recreation room has the original game running.
    • Leaving the game overview in the Situation Room screen has Bradford spout off some idle chatter every so often... with some subtle references to the original game.
      Bradford: "This is Central, I'm receiving you... what do you mean you think you saw a snake? What the hell does that have to do with anything?"
    • In Enemy Within's "Site Recon" Council Mission, Bradford remarks that at least the grounded ship the Chryssalids are spawning from wasn't a cruise liner. Terror From the Deep has very long cruise ship Terror missions, which are generally very stressful and tend to result in extreme death rates.
    • One of the UFO Retrieval Maps added in Enemy Within is modeled after the classic 1994 X-COM farmhouse terrain, complete with barn.
    • Zooming way in (usually during a cinematic action shot) in the "video rental store" part of one map will show a mohawk-wearing X-COM soldier from the original game, wearing that game's version of the Alloy Armor with cheekbone-helmet.
  • Nanomachines: Meld, cybernetic nanobots with both organic and mechanical components. They operate by allowing unprecedented synergy between organic tissue and mechanical parts (or between two incompatible organic tissues) down to the cellular level. It's the main material used in both genetic and cybernetic enhancements. As long as they're not killed with explosives, Mechtoids and Heavy Floaters yield 5 Meld when killed.
  • Nerf:
    • Blaster Launchers were downgraded from insanely powerful programmable guided missile launchers to merely flawlessly accurate and harder-hitting smart rocket launchers. The Blaster Launcher borders on a Cosmetic Award when compared to its predecessor, dealing out only a 50% increase in damage over the rocket launcher and the ability to shoot around corners (though the same limited view range) – useful, but not a Game-Breaker in the slightest. You get it by downing and clearing a battleship, the hardest challenge in the game unless you complete the Gangplank mission of the Slingshot DLC.
    • Chryssalids as compared to the original, though they're certainly still dangerous. They no longer instantly zombify your units *, and the zombies no longer need to be killed with fire to prevent a new Chryssalid from hatching (they can be killed within three turns with anything). Furthermore, Assaults can learn a special ability that gives them Reaction Fire against enemies that close in on them, useful against the melee-only Chryssalids. On a more fundamental level, Chryssalid's didn't cope well with the transition from the old "Action Unit" system to the new "one move, one attack per turn" action system. Since they're melee-only units, if they can't use their first movement to get within claws' reach of their target then they need to dash, using up their second action for the turn and resulting in them running up to stand snout-to-nose with an XCOM trooper... and then not attacking and subsequently being mown down by the entire XCOM squad at the start of the next human turn.
    • Enemy Within nerfs the near-game-breaking power of "Squad Sight", while actually buffing several skills that proved to be rarely chosen, like "Covering Fire" (reaction shot triggers before the enemy fires), "Close and Personal" (free standard shot if within 3 tiles of an enemy) and "Snap Shot" (only -10 Aim penalty when firing after moving).
    • Also from Enemy Within, instead of guaranteeing critical hits, Ghost Armor's cloak now only gives a 30% chance increase, while the cloaks from the invisibility grenade don't offer any crit bonuses. Mimetic Skin and Ghost Armor don't mix as well as it may seem at first either, as Mimetic Skin precludes using the Ghost function; thankfully, the grapple function, extra mobility and innate defense are intact.
    • Additionally, Heavies' "HEAT Ammo" ability only gives a 50% damage bonus against robotic units, compared to the 100% from the original.
    • Science got nerfed too; it takes a lot longer to research beam weapons and carapace armor, for one, so you are encouraged to capture more aliens alive and cut down on the research time for those. You are similarly encouraged to try to get more scientists and/or build laboratories, where in Enemy Unknown you could safely focus on getting engineers and nothing else.
  • Never My Fault: Played for Laughs in a news blurb for a low-panic United Kingdom, where a famous footballer who missed the winning shot claimed he was "blinded" by UFO lights during his match. Also doubles as a Shout-Out to the first Men in Black, in particular where a flying UFO actually causes a baseball player to miss a critical fly ball.
  • Never Split the Party: Letting a Squadsight Sniper hang back all alone or sending a lone soldier to flank some enemies worked in the vanilla game, but not anymore. Enemy Within invokes this trope with the Seekers, which latch onto isolated soldiers and will strangle them to death if another soldier doesn't rescue them in time.
  • New Game Plus: Second Wave mode. Initially only available via mods, it was officially added to the game in the January 7, 2013 patch for PC, while consoles got it as free Downloadable Content.
  • Nicknaming the Enemy: Aliens in general are usually called ETs or X-rays during combat*. Also, during the Autopsy cutscenes or reports, Dr. Vahlen mentions that several aliens' designations were originally nicknames the troopers came up with that stuck.
  • Nintendo Hard:
    • Classic and Impossible. For bonus points, Classic (or Impossible) and Ironman mode. And if that weren't enough, players can make the game even harder with the Second Wave optionsnote .
    • The random number seed is preserved... meaning that save-scumming won't let you "do over" that shot you just missed. If you missed it the first time, you'll miss it every single time you reload. The "Save Scum" Second Wave option completely negates this, should you pick it.
    • At any difficulty, keeping a perfect roster of funding nations is difficult, especially when you are still scrambling to build satellites. It only gets easier when you have enough satellite coverage and aerial firepower to reliably take down abductor ships.
  • No Cutscene Inventory Inertia: Impressively averted. While your units tend not to speak in cutscenes, changes like weapons and armor customization do carry over even during cutscenes.
  • No Help Is Coming: One achievement is called "Ain't No Cavalry Comin'". You get it for having at least one soldier participate in every single combat engagement against the aliens for the entire campaign. In other words, those who started the fight against the aliens have to finish it, without anyone relieving them.
  • No One Gets Left Behind: Played straight by a Support class perk, which allows them to revive critically wounded allies (albeit with minimal health and a long time in sickbay after the mission). Can also be cruelly Subverted, however, by choosing to abort a mission; doing so results in any soldiers near the Skyranger boarding and leaving everyone else to die.
  • No Fair Cheating: Turning one of your squad into a Hero Unit will disable achievements for that particular campaign.
  • No-Holds-Barred Beatdown:
    • When a Berserker manages to score a killing blow. The poor soldier is gut-stabbed and then hammer-fisted into the ground as they double over, and then the alien continues to savagely beat them for a few more seconds.
    • In Enemy Within, MEC troopers can get in on the action if they choose the Kinetic Strike Module on their MEC suit. There is even a special animation when used to kill Mechtoids, Berserkers and Sectopods, and this trope is definitely involved. The animation used when killing a Berserker with a MEC rocket-punch is especially awesome – the Berserker initially goes for this, but gets brutally shown that it's facing a physically stronger enemy for the first time when the MEC shoves it off them and delivers the Module's alien-mulching uppercut when the Berserker gets up for more.
  • Nom de Guerre: Bradford's is "Central", the Skyranger is "Big Sky" and your squad is "Strike-One". Also, any soldier that makes it to Sergeant earns one, though the player can change it to whatever they prefer. They're randomly assigned, though each class has their own list of available nicknames.
  • Non-Lethal Warfare: The Arc Thrower is your primary tool for capturing aliens. While useful for taking down aliens for interrogation, it's also essential for seizing any piece of handheld alien technology, which otherwise self-destructs upon the wielder's death. It also remains a useful tool throughout the mid-to-late game, as it's a lot cheaper - though much, much riskier - to stun aliens and jack their gear than assembling it yourself out of precious alloys and Elerium, even moreso in Enemy Within since the price of plasma weaponry is increased by 50% and the cost in Elerium and Alloys is doubled.
  • Non-Standard Game Over:
    • If you fail the very first tactical mission by losing all four of your initial rookies, you don't get the option to return to base. The Council of Nations immediately decides that the XCOM project is a failure and shuts it down. You do get the option of restarting the mission, though.
    • In Enemy Within, failing the XCOM Base Defense mission causes a game over, for obvious reasons. In the same vein as the first mission, you get to restart it if it goes too south. Even on Ironman.
  • No Range Like Point-Blank Range: The Assault class encourages this, especially in Enemy Within. Combining "Close and Personal" with "Rapid Fire" allows your soldier to run up to an alien, shoot them without losing an action, and then use "Rapid Fire" to shoot them twice more. If it's a Berserker and your soldier has "Close Combat Specialist," they can get off four shots in one turn if either the Berserker is drawn into the required range by another soldier or if they pull back slightly with "Run & Gun" before using "Rapid Fire".
  • No-Sell:
    • Titan Armor, for fire and poison. In Enemy Within, strangulation as well, and Ghost and Archangel Armor also gain the same immunities.
    • Medikits provide immunity to poison.
    • In Enemy Within, Respirator Implants for poison and strangulation. The Chitin Plating and Mind Shield items, as well as the "Bioelectric Skin" gene mod, grant immunity to strangulation.
    • A missed psychic attack goes like this. The dramatic camera moves to focus on the attacker, pans over to the target as the attacker releases psionic energy, and... the target doesn't react at all, and the interface informs you the attack failed.
    • Purely visual, but some of the miss animations have the shots hitting, but failing to penetrate the target's armor.
    • Major-ranked Heavies can No-Sell weak attacks, like those of Sectoids and Drones, if they're in cover and not flanked. Additionally, Colonel-ranked Assaults can No-Sell critical hits.
    • The Ethereal has the occasional ability to not only block incoming fire, but reflect it back at you, so that you take the damage. Doesn't count for explosive damage, they can't reflect bombs.
  • Not Even Bothering with the Accent:
    • Your soldiers are recruited from all over the world, but they all speak perfect American English. Adding unique accents for every single member nation would probably be overkill for the developers, of course, which is why they went with this instead. In Enemy Within, this has been changed: you can customize your troops to speak in one of sevennote  languages, whether it's their country's native tongue or otherwise.
    • No matter where EXALT's main base is located, the voice over for the ending cutscene is still an American-accented man referring to a radio/news station with an American naming pattern.
    • Dr Vahlen is supposed to be a German scientist and usually speaks in a Gratuitous German accent, but half of the time, she changes to overly enunciated RP. Apparently, her character had originally been meant to be British. note 
  • Nothing Is Scarier:
    • On some missions, either because of a larger than usual map or placement of enemies, it can take you a while to actually find the aliens if you're advancing slowly. This only makes you more nervous as you continue to worry about stumbling into a horde of Mutons or a swarm of Thin Men.
    • Or worse, when you've moved forward so quickly that you overextend and wind up with aliens behind you - but you aren't sure where they are, and you're standing in the middle of an alien base with Mutons and Chryssalids coming from god-knows-where. You have two options - split the party, or wander around hunting for the last enemies on the map. Or pull a six-way Back-to-Back Badasses Last Stand, because twenty turns in, the aliens have their fog of war removed so you don't wind up chasing the last alien all over the map. Bonus points if they all make it out alive.
  • No Transhumanism Allowed:
    • Doctor Shen has shades of this on Psi abilities. Then again, it's completely new territory and the only other users/examples are the invading aliens, so his hesitation is understandable. He's proven wrong, as the strongest human Psi user ever, The Volunteer, pulls a Heroic Sacrifice to save the Earth. He also questions if something as cybernetically enhanced as the Floaters can even be considered a true lifeform anymore, saying "if that is humanity's future, I want no part of it". The Uber-Ethereal reveals in the final mission that the Floaters were a failed project to create a resilient psionic species, and decided to rip out their organic parts to make them better weapons for the Ethereals' purposes.
    • Averted in Enemy Within, as soldiers can now be enhanced with Bio-Augmentation and Cybernetics. The expansion even changes Shen's voice line – instead of saying "I want no part of it", he expresses determination to proceed with cybernetic modification, albeit without sacrificing the MEC troopers' humanity. His stance actually gets rather amusing: his dialogue expressing concerns over things like Floaters and Psionic research remains, but when you sign up a trooper for MEC augmentation, he rather cheerfully informs you that "a chop here, a chop there, and soon we'll have a soldier the likes of which the world has never seen".
    • However, EXALT's bio-augmentations are taken to a level even Vahlen refuses to go. It shows when EXALT's gene-modded Elite troops have a sickly greyish pallor to their skin (and Heavies have a dirty yellow sheen), while boosted XCOM soldiers at most emit a small burst of vapor or energy at times.
  • Not Using the "Z" Word: Averted, though lampshaded: Dr. Vahlen can't believe she's using the word "Zombie". You can lean on her hesitance.
    Dr. Vahlen: "As unprofessional as it sounds, it appears the bite seems to have turned him into a... zombie."
  • Not Wearing Tights: Played with. XCOM operatives are never called superheroes, but by late game, you can have soldiers decked out in brightly colored, form-fitting armor that for all intents and purposes resemble superhero tights, armed with incredible psychic powers. And Enemy Within takes it a step further with access to genetic and cybernetic modification.
  • Oh, Crap!:
    • When things start to go against you in battles, your soldiers can freak out, panicking and losing their turn. The lower the soldier's Will score, the more likely they'll panic when another soldier dies or is mind-controlled, when they take a hit, or when a Muton calls them out with their Intimidate ability. When they panic, they can shoot a random target (with an Aim penalty and randomly chosen from your other troopers, visible aliens and civilians), run for cover, hunker down or just run in general.
    • Aliens (and EXALT soldiers in Enemy Within) can be forcibly panicked by Psi-Panic, and will act much the same way as a panicking XCOM soldier. They will not do so normally, however, though they will temporarily retreat and/or call for help if you quickly kill enough of them.
    • In a metagame sense, you'll be saying this a lot when you encounter a new alien unit and they unleash an ability you haven't seen before. Additionally, every time you see Chryssalids (early-mid game) and Sectopods (all the time, especially if there's more than one). You'll also be saying it an awful lot when you send a trooper into a room to take cover and clear up the fog of war when raiding a landed or crashed UFO... and then it turns out he's running into the middle of a group of Mutons.
    • One of the most common reasons for this is on your orders for the last soldier who hasn't acted yet. Dash forward without caution, and you may encounter a group of Chryssalids or a Berserker, who use their "enemy spotted" action to get as close to your troops as possible... then it's their actual turn to act.
    • MEC Flamethrowers in Enemy Within can make any organic enemy panic. That includes Chryssalids, Berserkers and Ethereals. What's better, the panic state that this induces makes melee and psi enemies completely unable to do anything but skedaddle in a random direction, presumably because they're freaking out too hard over being set ablaze.
  • Old-School Dogfight: Battles between UFOs and your interceptors are pretty straightforward aerial shoot-outs. While your initial aerial weapon are the Avalanche missiles, you can later develop and equip various cannons, which may force your interceptor to close in to dogfighting range. Crafting various modules in your base allows your interceptors one-time bonuses to Aim, Dodge, and Chase.
  • Omnidisciplinary Scientist: Dr. Vahlen and every scientist in the labs. They are all equally versed in biology and physics, everything short of engineering (which is the domain of the engineers, who are themselves downplayed examples as they can work into anything that fits under the umbrella of "engineering"). Which is presumably why they were hired in the first place.
    • Averted, just once, in a cutscene where Dr. Vahlen is trying to explain what the Outsider Crystal does. She's at a loss for words but then Dr. Shen steps in and says, "perhaps this is outside your field of expertise." (It is an antenna.)
  • The Omniscient Council of Vagueness: The Council, of course, complete with a mysterious man with his face framed in shadow who signs off by saying:
    "Remember, we... will be watching."
    • And although their entire style and word choice fulfills every Conspiracy Theorist's nightmare, they are in effect Reasonable Authority Figures who only complain if you slack off against the aliens. If you do exceptionally well (A rating), they make a point of pointing out how well things are going:
      "We are extremely impressed with the progress of the XCOM Project thus far, Commander. Your results are beyond our expectations, and that is not a statement this council makes lightly."
  • One Bullet Clips: Another change from the original games, ammunition is no longer tracked as separate items and soldiers can reload at will. Pistols never run dry, however.
  • One-Man Army:
    • There's an achievement for clearing a UFO crash site with just one soldier*. It's pretty tricky even with superior equipment and tactics, and you definitely shouldn't try it with a rookie soldier.
    • A single Snapshot + In The Zone Sniper with the Mimetic Skin gene mod can really cause terrible amount of casualties on the enemy side.
      1. Trigger the enemy's free movement for discovering your units.
      2. Break line of sight, and sneak around while concealed towards the enemy flank.
      3. Wipe out everyone not in cover using your Plasma Sniper Rifle, all in one turn with In The Zone.
      4. If any enemy survived the Kill Streak, simply break line of sight and go invisible again from Mimetic Skin.
  • Onesie Armor: In this game and XCOM 2 body armor is one single piece statwise, though various protective vests may be worn under it for additional protection as a utility item, and purely cosmetic Character Customization allows you to individually change headgear or body armor
  • One Size Fits All: All the suits of armor you manufacture can be worn by any of your soldiers. If you unequip an armor to put it on another soldier, the armor will instantly adapt to the sex, body build and class of its new owner. This is especially noticeable because the armors are rendered differently on screen depending on those parameters.
  • One World Order: Despite the ominous tones, the Council of Nations is a subversion. They're essentially a UN-expy of the world's leading countries who function more like The Alliance than anything else. Do poorly however, and your actions might splinter the Council apart as nations drop funding to fend for themselves.
  • O.O.C. Is Serious Business: The Council is almost impossible to upset. The chairman only expresses concern when several council members withdraw and even if you mess up a few times over the month he's still confident that you'll improve. But when you lose 8 council members he'll call you up and tell you that the XCOM project was a stupid idea to begin with that would never succeed. It turns out he's being mind controlled when he says that, and there's nothing you can do to stop him from shutting down XCOM.
  • Operation: [Blank]:
    • Every XCOM ground mission gets a two-element codename (e.g. "Operation Defiant Empire"). Most are random, but story missions and special council missions tend to have Meaningful Names. Non-story missions may, however, end up with Word Salad Titles.
    • Each research project has a codename (e.g. "Mobius"), which is unique to each project.
  • Our Weapons Will Be Boxy in the Future:
    • In full effect with XCOM's hardware, and most pronounced with lasers. The plasma weapons are decidedly not boxy, but rather rounded and (in some cases) cylindrical, but they're copied from the alien models rather than designed from the ground up. The Arc Thrower is essentially a cube sitting on top of a pistol grip. Also, going by the concept art and various in-game animations, they have a 'fold in' mode of sorts, so the boxy-ness is something of a design requirement.
    • EXALT weapons avert this, as their engineers took their existing gun frames and stuck the laser parts on.
  • Out-of-Turn Interaction: Reaction shots such as Overwatch lets units attack out of turn, and are triggered in response to enemy actions.
  • Outrun the Fireball: Once in the vanilla game, and again in Enemy Within:
    • During the game's conclusion, there's a double instance: The Volunteer is trying to get the Temple Ship into an orbit that won't destroy the world (running the fireball away from the target), while the remaining XCOM soldiers rush back to the Skyranger to escape the soon-to-be-debris Temple Ship.
    • In Enemy Within, during the "Site Recon" Council mission, an airstrike will be called in (for very good reasons). You then have a limited number of turns to get your squad to the evac point: if you don't, they will be blown up by the resulting detonation. The loss of an XCOM squad isn't much compared to the possibility of a Chryssalid apocalypse.
  • Outside-the-Box Tactic:
    • Overwatch and Suppression can virtually lock a unit into place, letting aliens scuttle about to flank the poor soldier... what's this, the soldier is grappling away without a single reaction shot? Yep, apparently, nobody is paid enough to shoot a target moving that fast.
    • Multiplayer-only, a Chryssalid killing a Sectoid who's Mind Merged with a human will zombify that human after the backlash kills them, pretty much giving you another Chryssalid free.
  • Palette Swap: EXALT weapons have the exact same stats as their XCOM counterparts. The in-game descriptions hang a minor lampshade on how unlikely the similarity is.
  • Paper-Thin Disguise: Thin Men are only nominally human-looking. Their proportions put them right in the Uncanny Valley, they've got reptilian eyes under their sunglasses and they've got green scales showing right around the collar line on their necks, like their human makeup is wearing off. They never fool your XCOM team. Openly carrying light plasma rifles and attacking the XCOM team on sight doesn't help either. But, you'll encounter only Thin Men in some of the Council missions, so their disguise may work on the civilian population.
  • People Jars: Genetically modifying a soldier requires them to step into a huge jar of Meld for 3 days per added gene mod. They're just fine once emerging, however.
  • Permanently Missable Content:
    • Certain aliens from early on in the game usually stop showing up after a few months, which can be problematic (though it won't render the game Unwinnable) if you haven't managed to capture them for interrogation. If you're lucky, though, they may occasionally pop up during Council missions or even regular ones. Hopefully, you've brought along an Arc Thrower. Slightly cushioned in Enemy Within, as the later game Mechtoids now appear with one or two Sectoids or a single Sectoid Commander in tow. Other enemies, like regular Floaters, still fall under this, though.
    • Unique council missions, such as Confounding Light have to be accepted and completed within days of being offered, or else they will go away and never come back. Skipping or failing a unique council mission also causes the player to lose the opportunity to participate in all future missions in its quest chain.
  • Pinned Down: The "Suppression" ability available to Heavies, Supports, and some aliens. It penalizes the target's accuracy and allows the suppressor to take a free reaction shot if the target moves.
  • Plasma Cannon: In various forms, this is the standard-issue weapon for the aliens, and the best (and most expensive) weapons available to XCOM.
  • Player Nudge: The game occasionally tells you the general direction some of the aliens are hiding in, so you're not left clueless for long.
  • Playing Games at Work: You can hear Bradford complain about someone doing this in the Situation Room:
    Bradford: Are you really using our tracking terminal to play Civilization?! I at least hope you're going for a Military Victory.
  • Poisonous Person:
    • The Thin Men: they're highly toxic and can spit poison clouds at your group. They also create a poison cloud when they die. Their toxins can be refined by XCOM into gas grenades.
    • Chryssalids can poison those who manage to survive their melee strikes.
  • Poke in the Third Eye: You can give a soldier the 'Neural Feedback' gene mod, that produces a mental rebound that damages any enemy attempting a psychic attack. The damage occurs even if the attack succeeds, so if a wounded alien mind-controls an agent with this trait, it might prove to be a rather short bout of control. If it doesn't kill the psionic, it'll put all of their psi-abilities on a forced cooldown. If one such soldier is targeted in any way by an Ethereal, the Ethereal is completely neutralized (aside from attack reflection) for at least one full turn.
  • Point of No Return
    • In the vanilla game, it's Merciful. The game warns you that the final step towards attacking the final ship will stop all progress anywhere else.
    • In Enemy Within, Nasty. The aliens assault your headquarters a few weeks after the Alien Base Assault, and it's always your five highest-ranking soldiers that you control in the defense. However, the expansion comes with a helpful button that lets you unequip all the gear of those not in your currently selected squad. If you use it often and are not currently leveling your heavy-hitters, this will result in your best troopers fighting off Cyberdisks, Berserkers and even Sectopods (depending on how far you are in the game time) with basic weapons and armor. Hopefully you kept your saves up to date.
  • Post-Mortem One-Liner: All unit voices come with some remarks following a successful kill:
    "He's out of the game."
    "Kill confirmed."
    "Dead and gone."
  • Post-Defeat Explosion Chain: Sectopods explode four times when destroyed. With Enemy Within running, the last explosion deals considerable damage up to four tiles away.
  • Powered Armor: The Titan Armor, which comes with immunity to fire and poison and grants a huge bonus to health. You also get an achievement called "Man No More" once you build one. The Archangel Armor is basically the same, but with a built-in jetpack and slightly less health.
    • The MEC suits technically count as powered armor, as they are worn like regular armor by the cyborg MEC troopers. However, they're so big they move into Mini-Mecha territory.
  • Praetorian Guard: The Muton Elites serve as this for the Ethereals. Whenever you see an Ethereal, he'll always have a Muton Elite or two as his personal guard, and any mission with an Ethereal around will involve multiple Elites as a roaming alien squad.
  • Precision Crash: UFOs shot down by your Interceptors will always crash-land in the wilderness, inverting this trope. In the Enemy Within expansion they might end up in populated areas, but only in a Conveniently Empty Building.
  • Pre-Mortem One-Liner:
    • Though not stated directly to the aliens, Assault class soldiers will issue one when you activate their "Run & Gun" skill. Made even more badass if accompanied by the Ghost Armor's invisibility and wrapped up with a provided Post-Mortem One-Liner:
      "Going silent." [cloaking]
      "Moving in for the kill."/"Gun 'em down!" [Run & Gun]
    • Sonetimes soldiers will utter "Good night.", in different tones of voice, when stunning an alien with the Arc Thrower.
    • Psionic troopers can also break out a bone-chilling one, or an Evil Laugh, when using their psionic abilities:
      "Your nightmare is just starting..."
  • Precursors:
    • The Uber Ethereal mentions "Them" who promised his kind ascension, but ultimately failed to deliver.
    • The Ethereals are Abusive Precursors to the other alien species, having uplifted them all to use as proxy soldiers, tools and psionic sustenance.
  • Pretentious Latin Motto:
    • "Vigilo, Confido" (possible translations include "I am watchful, I am relied upon".
    • Enemy Within adds "Mutare Ad Custodiam" (Change to Guard) and "Bellator In Machina" (Warrior in the Machine) for the Genetics and Cybernetics branches respectively.
  • Production Foreshadowing: News blurbs from as early as the vanilla game mention how there are quite a few alien sympathizers in the world's population, advocating peaceful acceptance of Earth's conquering. EXALT from Enemy Within is an entire faction made out of these people.
  • The Professor: Dr. Shen, the head of Engineering. He occasionally wonders out loud if XCOM's technology will be repurposed for war with other humans if the aliens are fought off, though he quickly decides that we can jump that hurdle when it comes.
  • Proud Warrior Race Guy: All of the Mutons. Shoot one without killing it or they gun down a XCOM soldier/unarmed civilian? The guy will likely come out of cover roaring and pounding his chest like no tomorrow, taunting you, probably scaring any rookie nearby. These guys clearly enjoy their job, and it's obvious why the Ethereals like having them as bodyguards.
  • Psychic Link:
    • Sectoids can use their telepathic abilities to boost the stats of their allies with an ability called Mind Merge: the target gets +10% to Aim and +1 HP for a turn. What you're not told until you figure it out for yourself is that killing the Sectoid that's boosting the other unit kills them both as a result of psychic backlash. In Enemy Within, it has different effects on Mechtoids, which gain a damage-reducing shield instead. Killing the Sectoid will only remove the shield and mildly damage the Mechtoid.
    • Killing an alien who has mind-controlled one of your soldiers doesn't harm the soldier, who is placed under your control again. There is a sole exception to this rule: In the final mission on the Temple Ship, when you kill the Uber-Ethereal, he releases control of whatever soldier he has undoubtedly seized control of, and all of the other enemies in the room explode; including any soldiers that the other Ethereals have control of. The ending triggers immediately afterwards, with the only thing left of your soldier being a scorch mark on the ground. Oddly, this does not prevent said soldier from appearing as a fleeing squad member in the final cutscene.
  • Psychic Powers: The Gift comes with many more abilities than the traditional mind control. Among other things, Ethereals can now reflect your laser and plasma shots back at you. Eep.
    • You can gain them yourself, with 5 different powers available to your "gifted" soldiers: "Mindfray", a damaging attack that also debuffs the target, "Psi-Panic", a panic-inducing attack, "Psi-Inspiration", an ability that bolsters your allies' Will, "Telekinetic Field", a telekinetic defensive field, and good old "Mind Control". The Volunteer gains two, the "Rift", which deals massive AOE damage, and a link to the Ethereal Hive Mind. Sid Meier has all of them.
    • There's also a strong implication that, while it's called "The Gift", implying that it's limited to certain especially talented people, it is possible for every human to develop psychic powers. For the purposes of XCOM, however, only those people that can be induced to develop their powers in a timely fashion are of use in the war.
  • Pure Energy: The Outsider constructs.
  • Punch-Packing Pistol: Foundry projects can increase the critical chance of pistols in general by 20% and their damage by 1 point; sadly the aim-improving project is bugged and doesn't work. A Sniper (or any lucky soldier if you're using Training Roulette) with Gunslinger deals 2 more damage when attacking with a pistol. The Plasma Pistol by itself rivals a ballistic assault rifle in raw firepower, dealing up to 4 damage; combined with those projects and Gunslinger, it's equivalent to a Laser Rifle that doesn't have to be reloaded.
  • Punched Across the Room: MEC Troopers with the "Kinetic Strike Module" in Enemy Within can do this to aliens if the blow kills them, often hard enough to send them right through a wall or cause cars to immediately explode on impact.
  • Purely Aesthetic Gender: Squad members' gender is determined by coin flip and has no bearing on gameplay; unless players go out of their way to avoid it, most squads will therefore end up with a roughly 50/50 gender split. There is, however, an achievement ('Flight of the Valkyries') available for winning a mission with an all-female squad, which you may just get because your best (or only) soldiers are all females.
  • Pyrrhic Victory: Narrowly averted at the end of the game. As the Temple Ship is destroyed, it begins to form a black hole of sorts that could swallow the entire Earth whole. Luckily, the Volunteer stays behind to bring the ship as far from the planet as possible before that can happen.

    Q-T 
  • The Quisling:
    • One of the Escort Missions has a politician who (supposedly) is in collusion with the aliens as the escortee.
    • Subverted in the game over cutscene. The Council decides to join forces with the aliens, but it is then revealed that this is because they are being mind controlled.
    • EXALT in the Enemy Within expansion is an entire faction of these, believing that the aliens will uplift humanity and take steps to sabotage XCOM's efforts to defeat them at every turn. While they aren't wrong about why the aliens are here, they are actively opposing the only faction that the aliens have an interest in.
  • Raising the Steaks: An unusual take. Chryssalids can implant their eggs in species besides humans, which would presumably create a zombie as well. The ones we see it demonstrated on are carcasses of sharks and large fishes, which new Chryssalids emerge from when you venture near, and they can use a whole whale as a breeding nest, which hatches a new bug each turn. This also explains the dead cows around Abductor ships.
  • Rage Helm: From the Slingshot Downloadable Content, the final helmet has a head-encompassing faceplate with a skull imprint, a la Emile and his distinctive helmet.
  • Rank Scales with Asskicking: High ranking units on both sides are nastier than their lower ranking counterparts.
  • Random Number God:
    • Will actually help you in the lower difficulties*, but you'll still endure the full capriciousness of His/Her whims in Classic* and Impossible*.
    • Notably, Abduction, UFO and Terror site appearances are all controlled by separate number gods. While it is extremely rare, it is possible to have to face mission after mission immediately, with no chance to rest in between. For example, an abduction warning followed by a UFO followed by a Terror site followed by another abduction. This can happen regardless of the difficulty level.
  • Randomized Damage Attack: The whole schtick of the "Damage Roulette" Second Wave option. Any form of damage that isn't an explosive, psionic or MEC subsystem will deal between 1 damage and 150% of the weapon's base damage. A Critical Hit deals the base damage plus the randomized damage.
  • Ranged Emergency Weapon: In the base game, pistols will probably rarely be used by anyone who isn't a sniper. Even with a Plasma pistol with all the Foundry upgrades, a pistol will only manage Scratch Damage against late game enemies. Snipers can take the Gunslinger perk to increase pistol damage. Heavies, on the other hand, don't even bother carrying pistols, preferring a rocket launcher instead.
  • Reasonable Authority Figure: Funnily enough, the Council of Nations is this. In any other game, they'd be the antagonist, but here, they provide XCOM with the funding they need to keep things running, request special missions that provide the second highest decrease in panic levels (next to successful Terror missions), and only complain if you're failing at your job to repel the alien threat.
  • Red Oni, Blue Oni: Dr Vahlen and Dr Shen. Dr Vahlen is enthused by the potential discoveries that can be gleaned from examining the aliens, while Dr Shen is concerned and disgusted by what the aliens use the tech for and whether humanity might wind up treading the same path.
  • Red Shirt:
    • Your Rookies at first. Piss poor aim, low health (and likely armor), and no special abilities mean that these unlucky guys can have an abysmal survival rate. Eventually becomes subverted as they grow in level and lethality.
    • XCOM base security personnel. No matter what level or how much gear your regular squaddies have, they'll still be ranked as Rookies and carry basic ballistic weapons and frag grenades (the latter even if you've researched alien grenades which allows you to mass-produce them). They're only used for the base defense mission as fodder, both due to the sheer number of enemies and the lack of choice in the soldiers and equipment you can use. And if they die, they aren't even included in your final loss count, and don't show up on the memorial.
  • Reed Richards Is Useless: Averted, provided you fulfill the requests that Council Nations sometimes make. Providing Thin Man and Sectoid corpses allow for major breakthroughs in medical fields, Floater corpses enable advanced prosthetic limbs, Arc Throwers make quelling riots easier, reconstruction is hastened thanks to advanced new alloys being available, and militaries (and even civilians, in some cases) can field laser and plasma weapons, as well as advanced body armor and enhanced electronics.
  • Renegade Splinter Faction: It's hinted that EXALT is made up of remnants of the original 1960s XCOM, having gone rogue at some point after the first invasion and now collaborating with the aliens instead of fighting them.
  • Renovating the Player Headquarters: The tunnels beneath X-Com HQ can be excavated and used to house facilities to assist you in your war against the aliens, such as labs to research alien tech, workshops to train engineers who keep your base running smoothly, or satellite uplink networks to increase the territory you can protect.
  • Retraux: Several character sheets of the aliens were released as promotional material and all of them included their sprite from the original game for comparison. What about the Thin Man, who was widely different from the Snake Man, you might ask? Why, the developers made an entirely new old-style sprite for him, of course.
  • Roar Before Beating: Floaters and Mutons.
  • Rocket Punch: In Enemy Within, one possible upgrade to your MEC Troopers is a "Kinetic Strike Module" which is fancy-talk for a rocket fist that can punch Muton Berserkers so hard that if there's a vehicle less than a few tiles behind it, the car explodes on impact.
  • Rocket-Tag Gameplay: Early-game works like this. Sectoids, Thin Men and Floaters don't have many hit points, but are armed with deadly plasma weapons that can kill or badly wound your rookies in one hit. Your rookies only have a smattering of hit points themselves, but their starting assault rifles and frag grenades are more than enough to kill the Sectoids and Thin Men in one hit (except on Impossible). Later in the game, when you have better armor and the hardier alien species show up, you'd better have a good understanding of tactics and teamwork when that Muton doesn't go down in one hit.
  • Rule of Fun: Weapons have been noticeably nerfed from their real-life effective ranges, but playing a game on the scale of hundreds of meters wouldn't be as fun. It would also be much harder to program and design.
  • Sacrificial Lion: The German Recon team from the tutorial. Most you will find on the street, disemboweled. The last one will be in the warehouse, giving Creepy Monotone shouts of "Hilfe", mind-controlled by a psionic alien. He cannot be saved and kills himself and one of your guys with a hand grenade if you come close.
  • Sadistic Choice:
    • Any time there are Abduction missions. You can only save one of the cities at a time and panic will rise on the continents you didn't deploy to. It takes some skillful juggling just to keep the panic level from going completely critical and, in the worst-case scenario, can result in having to decide which nation(s) you can afford to lose.
    • Can easily be invoked in Terror missions, where civilians are often placed such that you must decide between rescuing them and risk leaving a squad member exposed, or leave them at risk and keep your squad members safe.
  • Save Scumming:
    • Just as practical and common a technique as in the original, much to the chagrin of some members of the fanbase. That said, you can't just reload a game to change the outcome: The 'seed'* doesn't change when reloading a saved game. In layman's terms, Soldier A misses a 98% shot, he'll always miss that shot if you keep reloading from that specific save. You'll have to move another soldier, maybe have him fire, or just skip Soldier A's turn for a better probability.
    • Averted in Ironman modenote , which entirely prevents this. That being said, even in Ironman, most fans consider it perfectly legal to create backups of your saves in the event of a Game-Breaking Bug. Even on Ironman though, the game only saves at the beginning of your turn, meaning you can still get scumming by quitting the entire game and coming back. A do-over of even one turn can be golden on higher difficulties.
    • One of the new Second Wave options added to Enemy Within is explicitly called this, which removes the locked seed mentioned above, allowing a player to reload his game till he gets the desired outcome.
  • Scenery Gorn: Some of the new maps in Enemy Within are breathtakingly desolated. "Portent", the first map in the Operation Progeny storyline, stands out in particular.
  • Sci-Fi Writers Have No Sense of Scale: The No Sense Of Units variety. A news blurb mentions how the worldwide death toll numbers in the "thousands." Not hundreds of thousands, not tens of thousands, but "thousands." That number would barely take a dent out of a decently-sized city, and seems impossibly low given the large-scale destruction we see during Terror! missions. On the other hand, it could be that the official news reports are deliberately under-reporting the number of casualties to prevent panic from rising.
  • Screw This, I'm Out of Here!
    • During the "Site Recon" Council Mission in Enemy Within where you investigate a fishing village that's gone silent, your troops encounter a large number of Zombies and Chryssalids. About the time you discover the Chryssalids are using a whale carcass as a breeding ground, orders come to call in an airstrike. The rest of the mission involves running back to the extraction zone before the airstrike arrives, with the Chryssalids chasing you the whole way.
    • If you have this reaction during any other mission, you can always have your soldiers cut their losses and bundle back into the Skyranger.
    • If the panic level of a region is left unattended, the leaders of that region will withdraw from the XCOM program, taking their funding with them, in order to try and contain the situation in their nations by themselves.
  • Secret War: Zig-Zagged.
    • There is zero doubt among humanity that aliens are invading, given that their actions are public and tend to result in quite a few civilian casualties, especially after the first Terror mission. However, XCOM itself is a secret organization which is never publicly acknowledged, referred or alluded to by any public figure. The reason for this is never specifically stated, but is likely a result of the Sadistic Choices that XCOM is forced to make: they cannot protect the entire world all at once, and therefore have to choose who to protect. A policy of "protecting who we can by decisions you're not privy to" does not engender public trust.
      • This could also be an attempt to protect their HQ's location, resources, and strategic/tactical movements from overt discovery by the aliens (or any quislings hiding among the populace). This would be an especially prescient precaution given the psionic capabilities of the aliens.
    • Played Straight in the conflict between XCOM and EXALT. Both are secret organizations working covertly to undermine each other, XCOM exposing and eliminating their opponents' cells and EXALT working to sabotage XCOM's efforts. As EXALT members are never taken alive and XCOM retains plausible deniability, their shadow war is never known to the world. When you successfully storm their headquarters and put them out of business, you are shown a news broadcast where the attack is covered up and framed as a minor fire in a building that was successfully put out by the firefighters, with an ironic comment about how reassuring it is that the emergency services still work well despite the alien invasion.
  • Send in the Search Team:
    • The tutorial mission, "Operation Devil's Moon", has Delta Squad sent in to assist a German recon team that sent out a Distress Call. It ends with only one XCOM survivor.
    • "Site Recon" in Enemy Within has XCOM sent in to find out what happened to a Canadian fishing village that has gone dark, possibly due to alien activity, as well as the government response team sent to investigate. They're all zombies or Chryssalids now.
  • Sergeant Rock: As with Colonel Badass, some of your troops will probably end up like this. Can lean into Drill Sergeant Nasty with the right voice option;
    Support: [healing ally] "Rub some dirt on it you wimp!"
  • Serious Business: A news blurb from a low-panic Argentina reports how dedicated football fans refused to leave their stadium despite reports of alien activity nearby during a particular grudge match.
  • Self-Insert: The Hero Units include Firaxis staff and Ken Levine from 2K Games.
  • Sequel Hook:
    • The fact that the Uber-Ethereal mentions needing humanity uplifted for something did not go unnoticed by players.
    • In a meta sense, the game's overall difficulty (even on the lower settings), led to the question "What if XCOM got curb-stomped before they even invented laser weapons?" This is the premise of XCOM 2.
  • Serial Escalation: Deftly done to keep the game challenging. When you field new technology that will level the playing field, the aliens start sending even more powerful troops. Got those Plasma Rifles at last? Here come the Sectopods...
  • Shell-Shocked Veteran: It's perfectly possible for a Colonel to have been critically injured so many times during their career that their Will is low to the point where they make rookies seem unshakeable by comparison.
  • Shock and Awe: The vanilla game downplayed this trope with the Arc Thrower, which was only useful at stunning weakened enemies, repairing your drones or hacking enemy ones. Enemy Within turns that around with the MEC Trooper's "Electropulse" Tactical Subsystem, a close-range electric attack that fries any unit unlucky enough to be within a few tiles of the MEC, in addition to shutting down robotic units for a whole turn.
  • Shoot the Medic First:
    • Averted against aliens, as they don't focus on medics any more than other soldiers.
    • Zig-zagged when you're facing EXALT. Their Medics all have Field Medic, so they can use Medikits three times each, and Elites have regenerative gene mods that affect them and any EXALT units nearby. They also have Covering Fire, so they'll shoot back at any XCOM targeting one of their buddies. On the other hand, they tote neither the firepower of Heavies or the aim-increasing-when-hit gene mods of Elite Operatives, and their aim is atrocious, so if they're not close enough to help their allies, they're better left for last.
    • Drones are a mixed bag.
      • In Enemy Unknown, it was possible to down a Sectopod in one turn by concentrating most or all of your team's fire on it, meaning their Drone allies are nothing but a minor nuisance on their turn. In Enemy Within, Sectopods are so tough because of Reinforced Armor that it's unlikely you'll be able to get rid of them in a single turn, and if you leave their Drone allies alive they can effectively erase any damage you dealt on their turn. As such, it makes a lot of sense to kill the Drones first, especially with AOE attacks like rockets, grenades, or proximity mines that can kill the Drone outright and possibly damage the Sectopod as well.
      • In Terror Site missions, Drones will forgo their repairman roles to attack and kill civilians, which they're annoyingly effective at thanks to flight and innate defense. Shooting them is an absolute priority if you're going for the best ratings.
      • If you have Drone Capture developed in the Foundry, in non-Terror missions it's not bad to save Drones for last so they can be hacked with the Arc Thrower. A hacked drone is permanently in XCOM's side until the mission ends, and can serve as a risk-free disposable scout or autonomous grenade; if you're running a S.H.I.V., they can repair it from a considerable distance. But the most crucial aspect of hacking Drones is in Enemy Within: they can also repair MECs, and from far away. A hacked Drone or two make a world of difference if one of your soldiers during Operation: Ashes and Temples is a MEC Trooper.
  • Shop Fodder:
    • Damaged ship components and alien bioexperimentation equipmentlist and the like. Vendor Trash items are clearly labelled in your inventory as "having no use for research projects".
    • In Enemy Within, EXALT weapons are only cosmetically different from your own, including the basic ballistic weapons. Laser guns (especially sniper and heavy lasers) are a good addition to XCOM's inventory if you're too strapped for credits to make more of your own, but you already have an infinite supply of statistically identical weapons to their ballistic hardware, so you might as well make some money, but don't get too excited: they're only worth at most 3 credits each. Sometimes the Council asks for a batch of EXALT weapons, though, and they pay nicely for them. The raid on their HQ also yields a lot of vendor trash items like artwork, ancient artifacts and intel (that XCOM already has), and after the raid succeeds, the weapons can be freely sold.
    • After you're done with all your research and Foundry projects, weapon fragments can be sold freely for a little bit of pocket change.
  • Shout-Out:
    • The box art is an homage to Laser Squad, Julian Gollop's precursor to the original X-COM: UFO Defense.
    • Calling the infiltrator units Thin Men seems like a reference to a covert operative known only as the Thin Man in the film Metropolis. Clothes and hairdo are fairly similar (though the Thin Man in Metropolis does not wear glasses). You could possibly argue that there is some physical resemblance beyond thinness too.
    • To GuavaMoment's Let's Play of the X-COM series. One of the hero units is Otto Zander, the hero of the series. This can also carry certain unfortunate, unintended implications for people unfamiliar with the Let's Play, as Otto Zander was also the name of a prominent Nazi. (It should be noted that the name choice was intentional in said LP, considering the character development Otto underwent...)
    • Also several Achievements:
      • The achievement for building the base all the way to the deepest level available is called "Drums in the Deep".
      • Successfully mind-controlling an Ethereal unlocks "Xavier".
      • Winning a mission with an all female squad unlocks "Flight Of The Valkyries".
      • Staffing the research department with 80 scientists nets you "Oppenheimer".
      • Researching every possible research project gets you "Edison".
      • Building your first SHIV gets "You Have 5 Seconds to Comply."
      • Capturing an Outsider gets you "The Gatekeeper".
      • Winning your first multiplayer match earns "Meet New People. Then Kill Them." This is a reference to an unofficial US Special Forces motto.
      • "Skunkworks", for completing every Foundry Project, refers to Lockheed Martin's aircraft R&D department (officially the Advanced Development Programs), which produced such warplanes as the SR-71, F-22 and F-35.
      • "By Our Powers Combined!" in Enemy Within is earned by fielding a squad of MEC Troopers from all 4 different base classes.
      • Also from Enemy Within, you earn "Rise of the Machines" for fielding a squad of at least 4 made up entirely of S.H.I.V.s and MEC Troopers.
      • "Ours are the Furies", the achievement for completing the final mission of Operation Progeny, is a reference to A Song of Ice and Fire, where House Baratheon has the motto "Ours is the fury".
      • Yet another from Enemy Within, which is tied to a new mission type (Covert Operations, which are intended to disrupt EXALT cells and gather clues as to where EXALT's main base is): killing three EXALT troopers with the covert operative assigned to the mission gets you "Remington... Max Remington".
    • A soldier mind-controlling an enemy might say:
    • Bradford occasionally delivers several lines when you're in the Situation Room. Some of them are:
      "Are you really using our tracking terminal to play Civilization?! I at least hope you're going for a Military victory."
      "Some nut calling himself Commander Straker has been all over the news talking about 'SHADO agents'."
      "...and you're positive the report states that the alien craft crash landed in the garage of a suburban middle-class family... Tanner residence. Roger, we'll look into it."
    • Using the Arc Thrower to stun an alien results in soldier dialog. Some of the random bits that play are:
    • The Chryssalid autopsy research project is codenamed Ridley. Very appropriate.
    • One of the Cyberdisc's abilities is the Death Blossom.
    • The EMP Cannon research project's codename is "Ion". Ion cannons in the Star Wars universe function similarly to real-world EMP devices.
    • One helmet in the Slingshot DLC is obviously inspired by Emile's skull-patterned visor.
    • When one of your soldiers spots an alien squad, they might announce it by saying, "It looks like E.T. phoned home for backup."
    • Another achievement called G'day when you kill an EXALT Elite Sniper with one of your own.
    • One of the options you can select in Second Wave mode is the requisite that psionics can only be learned by interrogating psionic aliens. This option is called The Greater Good.
    • One of the possible clues to the EXALT headquarters' location is that it's "Not in a country you can play in Civilization V", another Firaxis game.
    • The Seeker autopsy research project is codenamed Lovecraft.
      • There's also a Council mission with a highly Lovecraftian feel: All contact with a fishing village in Newfoundland is lost after a strange ship arrives, and your team is sent to investigate. They even bend the rules a little to make the comparison better as the mission features zombified townfolk, even though they should've turned into Chryssalids by the time you get there.
    • Enemy Within introduces medals that you can award to your soldiers for buffs. One of them is named the Star of Terra by default.
    • The trope Fastball Special isn't actually used, but soldiers occasionally say this word-for-word when throwing a grenade.
    • The base defense mission in Enemy Within is code-named "Ashes and Temples", a reference to Thomas Macaulay's classic poem Horatius at the Bridge, an epic about Horatius Publius and his companions as they Hold the Line against assaulting enemies.
      Then out spake brave Horatius,
      The Captain of the Gate,
      "To every man upon this earth,
      Death comes soon or late.
      And how can a man die better,
      Than facing fearful odds,
      For the ashes of his fathers,
      And the temples of his gods?"
  • Shut Up, Hannibal!: A Sniper may do this to the Uber-Ethereal mid-speech.
  • Short-Range Shotgun: For emphasis, pistols will be more accurate than them at greater ranges for the base weapons. Later shotgun variants have better range to close the gap a bit. A tip will even mention using the pistol to make shots against far away enemies if equipped with a shotgun. Even more pronounced if Reaper Rounds are in use, as the range penalty is doubled.
  • Simple, yet Awesome: The Alloy Cannon and Carapace Armor, despite being cutting edge technology, are ultimately just a shotgun and a suit of body armor respectively. When these relatively mundane human concepts are suddenly upgraded with nigh-invincible alien materials, however...
  • Sinister Shades: Thin Men wear these in order to hide their Hellish Pupils.
  • Skewed Priorities: Save for few examples, aliens in Terror! missions will often target civilians even when there are soldiers about to shoot them.note 
  • Sleeves Are for Wimps:
    • The gene-modded troopers in Enemy Within wear lighter suits with no armor or clothing over their arms. No matter what armor or customizations, their arms will still be exposed. At most the armor's deco can be customized to include shoulder pauldrons and elbow pads.
    • Elite EXALT operatives can be identified by their rolled-up sleeves, which also exposes their tattoos.
  • Sniper Pistol: A curious zigzag. A Sniper with Squadsight that's put on Overwatch is able to take reaction shots with their pistol from Squadsight distance, much farther away than they can normally fire their sidearm. Thus far, nobody could tell if that's a glitch or not.
  • Spy Catsuit: The Psi Armor is very form-fitting, even if it's more armored than most examples. Tone it in black to complete the effect.
  • Sole Survivor: The tutorial mission ends with only Delta 2 from Argentina surviving. Losing three-quarters of your initial squad in the tutorial sets the tone for the rest of the game: it will not be easy. People will die.
  • Spare Body Parts: In Enemy Within, you can give your soldiers a second heart. This ensures that, rather than simply dying, they are always Critically Wounded the first time per mission their health drops to zero and extends their bleed out time, giving you a better chance to resuscitate them. As a bonus, they also don't gain the permanent Will penalty for having been Critically Wounded.
  • Suddenly Voiced: EXALT operatives normally have their radio chatter shielded by massive static and are otherwise completely silent - with no pain or death cries (unlike aliens), taunts, or other sounds... but if you hit them with a flamethrower, they completely lose their cool and start talking, usually saying how they're losing control of the situation or how they didn't sign up for this. Interestingly enough, some of them seem to have a slight Asian accent no matter what country EXALT is in.
  • The Spartan Way: As you lose your veteran soldiers, you'll need to bring in rookies to replace them. The problem is that rookies are much less capable, so there's a vital need to train them up - and the only way to do that is to send them on missions. The lucky ones get to tag along with the vets on a mission, which means that it's entirely likely that the first alien they'll see will be a Muton or Chryssalid. But if you have a Code Black with your vets, you may end up sending an entire squad of rookies on a mission that will definitely get some of them killed. But at least the survivors will be tougher for the experience.
  • Spiteful A.I.: During Terror missions, enemies will often attack civilians instead of your soldiers if they're in a situation where they only have one move before your squad ventilates them. Sometimes, they'll do it even when they're in a secure position and your soldiers make easier targets.
  • Spy Satellites: Used to search for UFOs outside of your main base's radar coverage. Keeping satellite coverage heavy is important to keep the various nations from withdrawing from the Council (and more importantly, funding you, as only countries with satellite coverage will give you monthly donations) and the aliens visible and chaseable. If you don't diligently shoot down UFOs with your interceptors, your satellites can be shot down, necessitating an expensive and time-consuming replacement. Fortunately, you can also research stealth enhancements for your satellites at the Foundry, making them harder for the aliens to find.
    • Satellite coverage has another, less-advertised result: if a country has coverage at the start of a month, it will no longer be possible for the aliens to start abductions in that country. Thus, in addition to giving you the continent-specific bonus, locking down a continent with complete coverage will stop its panic level from rising (assuming you don't fail any Interceptions, Raids or Terror Missions).
  • Starter Equipment: XCOM starts the game with awful conventional earth weapons. While they are passable on easy and normal difficulties, they are hopelessly outclassed by the aliens on Classic and Impossible, routinely requiring multiple shots even to kill the lowly sectoids.
  • Static Role, Exchangeable Character: "The Volunteer". To trigger the endgame, the player must send one of their organization's psychic soldiers into the Gollop Chamber to contact the Etherial Hivemind. This soldier becomes known as "the Volunteer" for the rest of the game, leads the assault on the final alien base, and must survive said assault because in the final cutscene, they perform a Heroic Sacrifice to save the Earth and humanity.
  • Stealth Mentor: One of the main reason of the Ethereal invasion is to prepare Earth for an upcoming larger invasion from an unknown enemy by sending their past subjects to be experimented on.
  • Storming the Castle: Two story missions and one optional mission.
    • The assault on the alien base, which will be XCOM's first encounter with advanced psionic abilities. Not that it slows the alien invasion much.
    • The final mission is an assault on the Temple Ship, pitting XCOM against the masterminds in charge of the alien invasion. Succeeding here stops the invasion in its tracks.
    • Once you finally narrow down the location of EXALT's HQ, you can choose to storm it to eliminate them as a threat.
  • Strong Flesh, Weak Steel: It is possible, with Titan Armor and Chitin Plating, to make a Major-ranked Assault tougher than an armored SHIV. Assaults gain an ability that gives them bonus health based on the armor they wear. With both the armor and plating equipped, an Assault can have up to 29 hitpoints, making them far more durable than even an Alloy SHIV, which can only have up to 18 hitpoints.
    • Subverted with the inclusion of the MEC Trooper, which can have the same amount of hitpoints by using a Tier III "Paladin" MEC Suit with the "Shaped Armor" Foundry Project. Coupled with abilities that allows a MEC to reduce incoming damage and even repair damage taken, MECs can often soak up more damage than an Assault can.
  • Stuff Blowing Up: Grenades and rocket launchers are extremely effective at completely blowing the stuffing out of the aliens. The downside is that they blow up any salvageable material (including Weapon Fragments, if you kill an alien with them) in their blast radius, but hey, if you get the opportunity to completely waste a group of weak enemies, then by all means, annihilate them! Better than losing your squad. Also, melee-only aliens like the Chryssalids don't provide Weapon Fragments in the first place, so feel free to blow them to pieces. They also tend to be bunched up when initially encountered.
    • You can also use them to just blow up the aliens' cover, allowing your other troopers to shoot them without an accuracy penalty. Using them to soften up a group of very tough enemies is also viable, as Weapon Fragments are only lost if they're killed with explosives (or if explosions hit their dead bodies and dropped hardware).
  • Stupidity Is the Only Option:
    • The tutorial involves the initial squad charging into unknown territory and subsequently getting ambushed while investigating a German soldier acting oddly. Because of the structure of the tutorial, it happens while trying to disarm the (armed, unresponsive) German soldier by sending one man to him in plain view before the team establishes Overwatch.
    • Even if you know your mind control ability is only temporary, you can't have your squad shoot or stun your mind controlled subject until he breaks free, unless you use up your limited amount of explosives. Having the aliens kill it for you gives your squad a Will penalty for the rest of the mission, since it's marked as a teammate while mind controlled, so that's out too. It gets ridiculous when one of your squad panics because a mind-controlled Sectoid gets blown up.
      • The Will penalty was removed in a patch, but you still can't preemptively apply a shotgun slug or Arc Thrower to their head. Of course, this also means that the aliens can't do so when they have your forces mind controlled.
  • Suicidal Overconfidence: Zig Zagged. Most aliens avert this; they'll sound the retreat, fall back to better cover and call for help if they feel they're outnumbered and/or outgunned. Chryssalids and Muton Berserkers play this straight; these two will (usually) charge ahead instead (note that they can move, but not attack in your turn), allowing you to shoot them point blank in the face. In the case of the Berserkers, there's a good chance an Assault can shoot one 3 times in one turn with the right abilities and when in the right position. Even Chrysallids will panic if flamethrowered, though for only one turn.
  • Superpower Lottery:
  • Super-Soldier: You can enhance your own soldiers into these, and come in 3 varieties:
    • Gene Mod Soldiers are genetically enhanced to have various superhuman abilities such as invisibility or the ability to detect enemy through walls. Gameplay-wise, they excel at sneaking around the battlefield while closing the distance to deal critical damage before the enemy even know what hits them.
    • MEC Troopers get their limbs cut off and augmented to properly interface with the MEC Suit. They lack the subtlety of biological soldiers (cannot take cover), but almost nothing can win against them in pure brute force combat. To put in perspective, they send Muton Berserkers flying with a punch, and two of them with upgraded Kinetic Strike Modules can pound a Sectopod from full HP to scrap in a single turn, with overkill damage to bootnote 
    • Psionic Soldiers are rare, and cannot be created on-demand. In exchange, they bring powerful psi abilities that can support allies or sow chaos among the enemy ranks such as Mind Rape or Mind Control. If you assign them as The Volunteer, they get the Rift power in addition to those. For extra fun, while Psionic Soldiers cannot be turned into MEC Troopers, they can be augmented by Gene Mods. Double the super, double the fun.
  • Super Spit: The Thin Men use this as a concealed weapon, hacking up clouds of poisonous gas from great distances to blind and choke any mammals trying to hide from them.
  • Surpassed the Teacher: The entire invasion was really a training program intended to uplift humanity to the point where we could serve as part of the Ethereals' army. Unfortunately, like most other alien invaders, they underestimated just how tough humans are. Assuming you win.
  • Surprisingly Sudden Death: Always a possibility, depending on your soldiers' health. Aliens can pop out from rooftops and kill soldiers in one shot, Berserkers can smash through walls to kill someone, even if you can't see them, and Sectopods can launch rocket barrages that can annihilate your squad from well beyond visual range.
  • Suspiciously Small Army: XCOM can only field 99 soldiers in total, which is barely more than two platoons at best, and then send a maximum of 6 soldiers to clear a city of aliens. It's established early on that XCOM is more of a black-ops unit tasked with assaulting key objectives, while leaving the heavy fighting to the rest of the Earth's militaries. Additionally, XCOM's mandate isn't to fight the war directly, but rather to win it, by identifying the aliens' weaknesses and exploiting them to stop the invasion. XCOM isn't a conventional military organization, but rather a very narrowly-focused, specialized unit, like a self-contained Delta Force.
  • Suspicious Videogame Generosity: Selling all the non-research artefacts gained, the aftermath of the alien base assault in Enemy Within is likely to be a huge payoff compared to all previous missions combined.
  • Synchronization: Sectoids may Mind Merge with other Sectoids to boost their comrade's abilities. If you can kill the Sectoid that initiated the Mind Merge, the psychic feedback will kill their friend.
  • Take Cover!: The biggest gameplay change over the original (aside from the removal of Time Units) is this. Your troops will hunker down next to various objects when possible and this is absolutely vital to not getting your soldiers' heads blown off. Technically, you could take cover in the original X-COM too, but only through micro-managing your troops' time units to duck out from behind walls before ducking back in; here, it's all automatic. Cover can also be destroyed by explosives and a few MEC abilities.
  • Take That!:
  • Take That, Audience!: Dr. Shen wonders if the aliens do dissections for fun, and then muses "At least they're not playing computer games..."
  • Take Your Time:
    • What's that? A gigantic ship huge enough to cause earthquakes where it pleases just appeared out of nowhere? It'll wait as long as you want for you to attack it. Which is exactly what it wants you to do since you'll be bringing your best Psionic Soldier on that attack.
    • Averted for Enemy Within if you intend to enhance your soldiers genetically or cybernetically. Those Meld canisters self-destruct after a number of turns that depends on how far away they are from your insertion point - the closer, the sooner. Take too long to discover and salvage them and they're gone for good. There are other ways to procure the stuff, but they're both less profitable and much more dangerous, so you better get a move on with a cloaked scout or two.
  • Technology Porn: Once you complete certain research projects, construct a building for the first time or manufacture certain weapons or vehicles for the first time.
  • Tech Levels: Ballistic Weapons < Laser Weapons < Plasma Weapons. Several class abilities refer to the weapon's tech level.
  • Teleporting Keycard Squad: Thin Men sometimes drop out of the sky after you complete some objectives in Council missions. The Slingshot Council missions have a Chyrssalid and several Mutons do the same, being air-launched from a Battleship. In Enemy Within, EXALT sometimes drop in from a helicopter during Covert Ops. On one pre-made map, an EXALT Sniper will fast-rope down onto the bucket of a large crane in the middle of the map, the instant you get within one turn of reaching the objective.
  • Theme Naming:
    • All the research project codenames for the various plasma weapons and the Alloy Cannon are various types of birds.
    • In Enemy Within, the three survivors rescued in "Furies", the final mission of Operation Progeny, are nicknamed "Alecto", "Megaera" and "Tisiphone", three of the Greek Erinyes, also known as the Furies. Two of them are actually twins, for extra points, the Saudis. The others are a French woman and an American man.
  • There Was a Door:
    • Your squad's A.I. will always use the straightest possible path to get to a given location, often causing them to smash windows en route unnecessarily. And of course, you can use rockets and grenades to create convenient 'shortcuts'. Similarly, it's not uncommon for characters to smash open adjacent windows in preparation to... fire in a completely different direction. Maybe it's just fun?
    • Explosives and the MEC's Power Fist are great ways of creating doors where there are none.
  • This Cannot Be!: The Uber-Ethereal when you kill him. Shades of What the Hell, Hero? as well. He believed that humans would willingly join the Ethereals to fight whatever bigger threat they were preparing for, and killing him destroyed their only source of information.
  • Throwing the Distraction: In Enemy Within, after you autopsy the Sectoid Commander, you gain access to the Mimic Beacon. It makes noise and lures every single alien not currently in combat towards itself; results vary on enemies currently engaging your troops, but Berserkers and Chryssalids tend to ignore all targets in favor of standing on top of the Beacon. It's an absolute must in Terror missions to get an "Excellent" rating on civilians saved.
  • Title Drop: The tooltip for "Autopsy Required"note  starts off with "Enemy unknown".
  • Too Dumb to Live:
    • Civilians during terror missions. They consider the best response to rapidly approaching, murderous aliens to be as follows: bend your knees a little, stick your arms out, and slightly twist your upper body back and forth, and they only have the common sense to move away from the aliens when they're ridiculously outnumbered. Fortunately, the proximity of XCOM units suddenly reminds them they're capable of running away at such speed as to escape the map in one movement. Civilian units during escort missions, thankfully, are player-controlled.
    • The Berserker charges at the first enemy he sees. Thereafter, he charges at whomever hits him. Position your team in a crossfire and you can have a hilarious game of monkey-in-the-middle with the big dope until he drops.
    • Heavy Floaters will sometimes drop their grenade right on top of themselves.
  • Torture Technician:
    • Not a character, but a continent: South America's continent bonus is called "We Have Ways", allowing XCOM to perform Autopsies or Interrogations instantly. Pain is the universal language!
    • Dr. Vahlen, who designed the interrogation system, an off-screen process which avoids the translation barrier by almost literally ripping the information out of their brains and/or implants. Officer Bradford admits that he is a bit creeped out by her methods.
      • The end of the first mission in the Operation Progeny mini-campaign in Enemy Within has Bradford explicitly mention how Dr. Vahlen is also good at interrogating humans!
  • Totally Radical: Some of your soldiers' order confirmations veer into pretty silly territory.
    (When moving): "Starting to motor!"
    (When moving): "Roger dodger!" (A reference to a Second World War story, where, in the expanded form "Roger dodger, you ol' codger!", it forms part of the punchline.)
  • Total Party Kill: If your entire squad gets wiped during a mission, the mission debriefing is given the designation: "Code Black".
  • Tragic Monster: In a way, all the aliens qualify. Each of the subservient species had their own civilizations until the Ethereals 'tested' these civilizations for psychic potential and mutated and/or enslaved the losers, which is currently all of them. When each race was finally deemed as "failures," they were then simply converted into proxy soldiers and outright cannon fodder for the Ethereals' future invasions. As for the Ethereals themselves, they (or at least their equivalent of Pope) view themselves as failures in the eyes of their deities, having failed to ascend to a higher plane of existence, and started this unholy crusade in a desperate attempt to find a psychically superior species to take over their empire for them (or possibly Grand Theft Me that race, but they still view their own species as the biggest failure of all).
  • Trailers Always Spoil: Some of the trailers for Enemy Within spoil the attack on XCOM HQ.
  • Transforming Mecha: The Cyberdiscs can transform between a nigh-invulnerable but unarmed disc form and a vulnerable but heavily-armed floating insect-bot form.
  • Transhuman: In Enemy Within, you can use Meld to enhance your soldiers beyond the limitations of the human body. This can be accomplished either by granting them genetic augmentations that grant them advantages of the invading aliens (second hearts, psychic defenses, improved depth perception), or transforming them into cyborgs.
  • Trick Bomb:
    • The Support's Smoke Grenades, which can also be enhanced to double as a combat stim that buffs your troops, or just provide extra-thick concealment fog.
    • Enemy Within introduces several new grenade types.
      • Needle Grenades cover a wide radius but don't go through cover (useful if you don't want to shred cover you intend to take, or have a guy hiding right behind a chest-high wall next to a bunch of Thin Men).
      • Ghost Grenades turn everyone in the area invisible for a turn, perfect for sneaking around enemy interception shots or patrols.
      • Mimic Beacons send out decoy noises to draw enemies into your kill zone.
      • Flashbangs greatly reduce enemy's movement and aim, as they stumble around blindly. Psionics are immune.
      • Gas Grenades poison enemies and force them to avoid the poison clouds (and their aim is terrible when they're poisoned).
  • 24-Hour Armor: A funny glitch in the core game: equip your soldiers with Titan Armor, and you can see them relaxing, eating and exercising in the Barracks with it still on. Enemy Within fixes this.
  • 20 Minutes into the Future: The game is set in 2015, but the world is almost exactly the same as it was on the game's release date in terms of technology and geopolitics, with a few exceptions. For example, military technology is slightly more advanced, Scotland seems to be an independent country, and gas costs around nine or ten dollars a gallon (though the last may be due to the alien invasion rather than an ongoing energy crisis).
  • Turn-Based Combat: The game implements the One Side, One Turn variation with Square Grid movement. Each unit has two actions, move and attack (although you can't move after attacking). Orders are given to each unit individually and resolved immediately, and you can switch between units that still have actions at any time. The system has both Delayed Actions (the reaction shot that replaces a usual attack and is triggered by an enemy coming into range) and Attacks of Opportunity (the Assault class' free close range attack).

    U-Z 
  • Unobtainium: Elerium and the alien alloy. Neither of them can be found on Earth or artificially created (yet. Both Dr. Shen and Dr. Vahlen muse that, with a few years of concentrated research, they could make the stuff become widely available.), meaning your only source is from the cold dead hands of the aliens.
  • Unusable Enemy Equipment:
    • Alien weapons self-destruct when they're killed even if you don't use explosives (if you do, you won't get even the fragments). You can, however, capture intact alien weapons if you use an Arc Thrower on the enemy. You still can't swap them mid-mission, as flavor text explains they're not built with human ergonomics in mind and need retrofitting for human use.
    • In Enemy Within, EXALT weapons are recovered after missions and can be used by your own soldiers. However, they're mechanically identical to your own weapon counterparts and are meant to be sold to the Council once you decide you have enough. Their only use in equipping your soldiers is a personal aesthetic preference over the X-COM gear. However, Elites' laser hardware are a way to get usable laser weaponry without having to spend your research dollars for it. Played straight with the unique gene mods on most of their Elite units, which are "Iron Skin" (Elite Heavies)note , "Regen Pheromones" (Elite Medics)note  and "Adrenaline Rush" (Elite Operatives)note ., and curiously, the Medics' Medikits. EXALT Elite units also carry alien grenades, which self-destruct into fragments upon death as with aliens, but are recoverable if the EXALT is stunned, despite their ensuing suicide.
    • Completely intact UFOs can't be commandeered after being secured, even if you've reverse-engineered their navigation, power and propulsion systems. They can only be dismantled for their components and raw materials. Then again, once you reach the late-game, you don't need a commandeered alien ship, as XCOM's Firestorm aircraft with fusion lances can handily win dogfights with anything the aliens send at you, even the mighty battleships.
  • Unfinished, Untested, Used Anyway: Par for the course, there being a war on and everything. Your base includes a laboratory full of scientists feverishly reverse-engineering captured alien tech and sending your soldiers into the field with hastily cobbled-together prototypes based on principles that aren't fully understood and concepts that were entirely unknown mere days before. They all work perfectly.
  • Uniqueness Rule:
    • Rockets. Since the Heavy Class is carrying a light machine gun (the heaviest weapon in the game), he is already very burdened, so he can only carry one rocket, with no way to resupply during a battle. Well, technically, if he takes the right promotion perks, he can use two rockets and a special shredder rocket (which causes less damage but inflict a Damage-Increasing Debuff), still, with a maximum of three rockets, make them count.
    • All active items work similarly. The medikit gets one use (three with a Field Medic Support), four when he gets Deep Pocket in Enemy Within), grenades can only be used once (twice with the Grenadier Perk from the Heavy, or the Deep Pocket support ability in Enemy Within), the Arc Thrower can only be used twice (thrice with the Support ability Deep Pockets), the support Smoke Grenade can only be used once, twice with the Smoke And Mirrors ability (thrice in Enemy Within). It had to be noted it applies only during missions, as the squad gets resupplied for free between missions.
    • In the expansion XCOM: Enemy Within, there is a scripted event involving an alien attack on your base (if you lose this mission, it's Non-Standard Game Over for you). The means the Mind Control the aliens use on some of your techs to get them to sabotage your base defenses is stated to be a one-off.
  • Unstable Equilibrium:
    • Early-game is typically the hardest part of the game. You've got no territory, little income, inexperienced soldiers, no technology and the aliens outnumber you. Later on, you have the option of getting goodies that even the aliens wish they had and soldiers with Improbable Aiming Skills who can mow down aliens like Rambo even with basic ballistic weapons and snipers who can pop the aliens' heads from across the map. Then psi powers enter the game, and the rules change... and again, once you have one or more psi troopers of your own. By the time you get the first Council request for plasma weaponry with a profit of over 1,000 credits, you're set for the rest of the game money-wise and will only have to grind some for alloys and Elerium to fuel Firestorm and plasma weaponry production and the later Foundry upgrades. Some veteran XCOM players call this the "snowball effect": at first, your chances of victory seem very low, as low as a snowball's chance in hell, but as you gain momentum from research, development and more advantages, the snowball quickly gets bigger as it rolls until you're overpowering your previously unstoppable enemies.
    • Another, shorter term example can be found in missions themselves. Having a squad member (or multiple) panic puts them out of commission for at least one full turn, making it harder to take out the enemies that caused the panic in the first place. Having a squad member downed (either critically wounded, stabilized but not revived, or outright dead) makes the entire mission harder, as every remaining turn will force you to exercise less firepower (and lose limited usage skills and equipment as they're unavailable for other soldiers to pick up and use). If you start with a squad of 4 - 6 and get down to just 1 or 2 soldiers, your chances of success drop so dramatically that you're better off restarting or hightailing it back to the Skyranger to abort. This is especially notable on Terror missions (or any early game mission with Chryssalids, really), as losing a soldier to a Chryssalid's bite (not the poison) will turn it into a durable and strong zombie that can eventually turn into another Chryssalid, potentially causing a downward spiral into Total Party Kill if you're not careful. In the late game, just replace Chryssalids and their ability to reproduce with Sectopods and the sheer firepower that they tote and that you need to bring one down.
    • Panic causes every mission to potentially be this on higher levels. Panic can be triggered by many things, such as seeing an ally hurt or killed, but also from being shot or blown up or attacked in general. This can easily cause 'panic chains', where one ally panicking triggers a second to panic which triggers a third to panic etc. Panic soldiers can also sometimes shoot allies, and since your soldiers usually are not positioned to cover themselves against their allies and are very close a panic soldier is far more likely to successfully hit an ally then the enemy is. This can do damage or kill other soldiers, which can *also* trigger another panic. The end result is a single unit panic can result in most of your team panicking and then being left vulnerable for the enemy to next turn, allowing the enemy to potentially land hits or kills next turn, which can of course trigger a new chain of panic. If all this wasn't bad enough, high difficulty games tend towards a variant of Rocket-Tag Gameplay where the priority is to avoid attacks because most can be a One-Hit Kill. This all combines to missions tending towards one of two outcomes: either you move in quick and kill the enemy before it can hit you, clearing the fight without any damage, or the enemy lands a hit on you, often scoring a kill, and the resulting panic and lost firepower means you suffer large casualties or TPK. There is little middle ground. Later on, when you have access to the panic-nullifying Neural Damping and soldiers trained under the enhanced Will gains from the Iron Will upgrade from the Officer Training School, it's harder to lose control to panic unless you're taking several rookies to earn promotions and their colonel nanny gets unfortunately splatted.
  • Urban Warfare: All alien abductions and Terror missions take place inside major population centers. Enemy Within adds Covert Operations against EXALT and even a few urban UFO crashes to the list.
  • Updated Re-release: Unlike the PC version, Enemy Within was released as the Commander Edition for the PS3 and Xbox 360, which includes the base game and all Downloadable Content.
    • The PC version plays with it. While the game is still called Enemy Unknown in the Steam game library, Enemy Within adds a game launcher that lets the player choose between playing the original Enemy Unknown and the expansion.
  • Uplifted Animal: Most of the aliens that serve the Ethereals have been conquered and uplifted or altered to some degree in their search for "gifted" species. The Chryssalids are the most striking example, since they began as feral animals... and didn't really evolve from that state.
  • The Very Definitely Final Dungeon: The Temple Ship, which shows up floating ominously over the Atlantic Ocean after you recover the Ethereal Device.
  • V-Formation Team Shot: On the box art. Also, your team prior to deployment will stand like this, allowing you to review them and their gear, standing around, looking awesome, with appropriate rockin' music playing in the background. Contrast this with the after mission summary, especially when things go south.
  • Video Game Caring Potential:
    • Unlike the original game, you'll (probably) get attached to your soldiers this time, and not just treat them as Red Shirts. Especially the Argentinian Heavy from the tutorial. Go ahead, see if you don't at the very least change their nicknames based on the game's events.
    • There's even an achievement, called "Ain't No Cavalry Comin'", which you earn if you take a soldier through every single mission. It's not enough to merely have him/her survive from the very start until the end of the game, but he/she must take part in each and every mission you take on. If you play with the tutorial enabled, this soldier will inevitably be the aforementioned Argentinian Heavy because he's the only one to survive the tutorial mission, which does count towards the achievement.
    • Name your soldiers personally if you really want to get attached. Go ahead, name one of the soldiers after someone you know and care about deeply and see how much care you take in not getting them blasted by an alien. This does lead to awkward explanations to your loved ones of how their name ended up on the memorial wall because of misplays, though.
  • Video Game Cruelty Potential:
    • The medal system of Enemy Within encourages this. A limited number of medals can awarded at any given time, they provide stat bonuses to units and thus are desired to have on your best teammates. Early on your need to assign them to your team to have any hope to survive the early game; however, it's possible for your original soldiers to fail to become psychics, and game mechanics mean newer teammates will often have better Will, used by psychics and to defend against it, than your original soldiers. Thus at some point you'll likely want to retire your original batch of soldiers for newer psychic powerhouses. This is when you discover you can't reassign medals from the old ones to the new. You could sacrifice useful medals by leaving them on unused soldiers, or you could remember that medals can be reassigned after death and 'retire' the old medal winner by arranging for an unfortunate accident during a mission.
    • Have four Heavies? Four civilians next to a truck you wanna use for cover? Now, sending in anyone to rescue them? Nah. Sending a rocket to blow it to hell along with the four civilians? Yes! Earning an Excellent rating? Check. Technically, you only need to save one civilian for the Terror Mission to be considered successful, provided you wipe out the aliens. So once you tagged that one cowering civvie, you can just go to town blowing everything up. Hell, you can shoot the civilians too if you want.
    • Rookies cost about §10 (Easy/Normal) - §15 (Classic/Impossible) each, which is pretty cheap (except very early on in the game). If one pisses you off by repeatedly missing the alien they're standing next to, the options always exist of making them go check out the scary noise in the building on their own, or drawing fire, or just plain being used as bait.
    • Is there one little Sectoid left on the map? Have an Assault with Ghost Armor and an Alloy Cannon? It WILL bring a smile to your face when you decorate the wall/tree/car/bulkhead that Sectoid is hiding behind with its innards.
    • Is there a single Muton Berserker left on the map? Can one of your soldiers use Mind Control? Now take the Berserker, move it to an open area with no cover, then have your squad line up in firing range, turn on Overwatch, and wait for the Mind Control to wear off. Cue More Dakka.
      • Better yet, in Enemy Within. Is that Berserker close to one of your MEC units? Does it have the "Kinetic Strike Module"? Punch it clear across the map. It gets even better if it's an EXALT agent. You can punch them into cars so hard the cars explode.
    • Mind Controlled a Muton, Elite Muton or Heavy Floater? Does he have buddies around? Why not have him stroll over to his friends and then casually drop his own grenade at his feet?
    • In Enemy Within, MECs can be particularly effective anti-robotics troops. Killing a Cyberdisc with a Kinetic Strike Module will send its explosive corpse flying like a flipped coin, allowing it to be used like a grenade against other enemies or even its own Drone allies. Similarly, a MEC can launch a proximity mine near one or more Drones so that they'll instantly get killed the moment they try to move to heal one of their allies.
    • Chryssalids are right bastards, which makes the options of torturing them oh so satisfying.
      • Launch a proximity mine on top of a Chryssalid pod that either wasn't activated (MEC Troopers can launch grenades and mines beyond their sight range, and unactivated pods won't react to a scout that they can't see because of height advantage or concealment from Ghost Armor/Mimetic Skin) or is moving as one (usually in downed UFOs since there are no juicy, squishy civilians to go after, so they have to settle for the juicy XCOM meatbags). It's effective on every singe situation where this scenario pops up, as 'lids never have more than 8 health on any difficulty and mines deal exactly 8 damage, so it's a guaranteed kill on every single one within the blast radius. It's guilt-free, too: since 'lids don't drop weapon fragments or Meld, you're 100% free to wreck their faces with explosives. Good way to give that low-rank inaccurate MEC Trooper some combat experience, too.
      • The Flamethrower is the earliest hard counter to Chryssalids: MECs can pick it as the very first level, a basic one will bring them down to 2 HP, and Jellied Elerium or "Absolutely Critical" enabled equals instant death if it touches the buggers. The cone of fire can cover an entire pod of them, too. The basic flamethrower also has the fun factor of making them panic.
      • A whole squad with Archangel Armor utterly negates them, since they can't attack airborne targets at all and will do nothing but skitter around. If you're lucky enough that the Site Recon mission pops up after you get said armor and Advanced Flight engineered in the Foundry, an otherwise terrifying mission becomes a massive turkey shoot that you can use to level up the New Meat.
      • Exploiting "Instant Death" Radius is pretty fun too. Just put your heavily armored Assault with Close Combat Specialist or S.H.I.V. with Sentinel Drone within their movement range, and watch as the reaction fire shreds the shredders. If they get close to an offense-oriented MEC Colonel, a claw-kick won't do much besides provoke a monstrously combat-capable cyborg with poison immunity and far too much HP for them to one-shot, and trigger a reaction shot from Reactive Targeting Sensors at a range that even the most aim-deficient MEC won't miss.
  • Video Game Randomizer: The free "Second Wave" DLC gives the option to randomize several elements that are static in the base game, such as weapon damage values, funding levels provided by Council nations, and soldier statistics. The Training Roulette option randomizes most class abilities, allowing for combinations not possible in the base game.
  • Video Game Remake: The core gameplay is X Com UFO Defense updated with more modern hardware in mind. The overall geoscience and battlescape gameplay, as well as the need to adapt alien technology for human use is present with tweaks for a more streamlined experience. The plot is almost the same as well.
  • Violation of Common Sense:
    • One wrong click, and you sent a soldier out of cover with a Sectopod warming its laser cannon in anticipation, and your remaining two soldiers have no moves that can affect the enemy's hit chance. If the Sectopod is the only enemy, just have them run out of cover as well, standing two tiles apart from each other. When presented with a delicious cluster of enemies stacked too far away to hit with one laser blast, the Sectopod will use its first turn to charge Cluster Bomb, ending its turn and giving you a free move to escape.
    • Sometimes, if you're very confident in your air defense network, it can be wise to completely ignore an alien UFO contact. If you do that, be sure to purchase some of the Interceptor modules and prepare for the battleship that will come for you. The reason is that a battleship can be quite lucrative if you manage to take one down and secure the remains, and they're quite rare (especially on lower difficulties) unless you let the game drag on for quite a while.
    • Have a soldier about to be killed by a wounded Chryssalid? Throw a grenade at them. If the Chryssalid has only three HP it'll be killed no matter what, and even if the damage kills your guy you don't have to worry about him becoming a zombie.
  • Viral Unlockable: The achievement "Bubonic" is unlocked by playing an online game with someone else who already had the achievement unlocked.
  • Virtual Paper Doll: You can customize your soldiers to a great degree, particularly in Enemy Within. Names, nicknames, physical appearance, armor color, voice, language, and hats are just some of the things that can be modified, which makes it all the more painful if they get killed.
  • Vomit Indiscretion Shot: Zombies will violently heave on their third turn. It's a helpful visual reminder to deal with it before you have to stop worrying about the zombie and more about that new Chryssalid.
  • Walkie-Talkie Static: "EXALT Activity!" plays this sound when it's EXALT's turn during a covert op, and they also seem to make this noise to each other when communicating. It's completely undecipherable. If an XCOM soldier under Mind Control calls out, they'll make the exact same noise.
  • Wake-Up Call Boss:
    • The Chryssalids, especially on harder difficulties as losing the first Terror mission will squad wipe, automatically cause the targeted country to withdraw, and probably put nearby countries into full panic as well.
    • Regular Mutons and Heavy Floaters are not-so-subtle nudges that it's time to upgrade to Laser and Plasma weaponry respectively if you haven't already.
    • On Impossible difficulty, Thin Men. They appear before the first month is over, have 6 HP each (double what they have on Easy/Normal) and can do up to 6 damage on a non-critical hit. Given that most of your soldiers won't even have 6 HP at this point, nearly any successful shot from a Thin Man will result in a One-Hit Kill. They also often attack in groups and have very high aim, not to mention also being able to poison you. They are still threats on lower difficulties, but not to the same extent.
    • The first EXALT covert mission in Enemy Within can be a jolt to players used to fighting only aliens, particularly if an EXALT heavy manages to kill two or three of your troopers will a well-placed rocket on the second turn.
  • Wall of Weapons: Between the Barracks and the Control Room is the Armory, which naturally sports one of these. It only displays ballistic weaponry, however.
  • War Memorial: In the Barracks you can go to a memorial to fallen soldiers, which will list all of the units that have fallen in gameplay (including the three killed off in the tutorial mission). Strangely, any base security personnel killed during the Base Defense mission are not listed on the wall. Apparently, they're not important enough, despite being willing to defend their base from heavily-armed aliens with the most basic body armor and weapons.
  • Wave-Motion Gun:
    • The Sectopod has two: a fusion lance for burning your dudes to a fine, fine ash, and a plasma beam for the reaction shots.
    • The Battleship UFO has one, which can be researched for your Firestorms if you salvage an intact Fusion Core. They're also used for Blaster Launchers.
  • We ARE Struggling Together:
    • Averted for the most part. The Council is made up of most of the G20 countries and a few others that give you money and support to keep everyone alive. That said, countries will bail if they feel they would be better off on their own.
    • Several news blurbs mention how many rival political and intellectual groups are blaming the alien attacks on each other.
    • This is why Zhang defects to XCOM during the special Council missions included in Slingshot. He realized that the Triads squabbling for money and power is kinda pointless when the Aliens are attacking everyone.
    • Finally played straight with Enemy Within. EXALT is another human faction that seeks to use the alien's "gifts" to empower themselves and directly opposes XCOM.
  • We Buy Anything: The good ol' Gray Market is the secret auction house for XCOM's funding nations. If you don't think you're going to be using that pile of already autopsied corpses and wrecks you don't use in crafting items or Foundry projectslist you may as well sell them for moneynote . In the early game, this will probably be your primary means of income.
  • We Can Rebuild Him: Enemy Within offers some... possibilities, here. Got a really badly wounded soldier who won't be back in action for a month or more? Turn them into a MEC! Sure they're stuck as a Man in the Machine, but they'll recover in half the time (or less!) and they have shiny new robot limbs!
    • Unfortunately, you can't rebuild a MEC Trooper (or any soldier for that matter) that was KIA. You can repair the MEC and place a new MEC trooper inside, though.
  • We Have Reserves: The aliens certainly seem to work off this mentality, as does EXALT in Enemy Within. Losing several high-ranking troopers midway through the game can make you do it as well. Throwing dozens of rookies into the meat-grinder can yield a handful of solid squadmembers via Darwin.
  • Weird Moon: Each return trip from a mission shows your Skyranger flying toward a full moon on a clear night, no matter what the date or Mission Control time actually is. To top it off, it's an unskippable in-engine animation so you will be seeing it quite often.
    • Additionally, most maps take place either at night or at day. Most maps don't switch between the two time periods, so it is very likely that your soldiers will arrive to the mission at noon only for it to be as dark as midnight. Also inverted by the times you deploy on a map where the sun shines bright even if it's 3 AM.
  • Welcome to Corneria: The original game had this problem with Bradford's limited, often-repeating mission briefings, but Enemy Within rectified it somewhat by adding more descriptions.
  • What Happened to the Mouse?:
    • One of the Large Scout ship maps has an empty, still-running truck belonging to someone who came to investigate and left a trail of flares leading to the ship. This isn't commented on, and nowhere in the map is this person's body, living or otherwise.
    • Most of the Escort mission VIPs as well. Anna Sing, in particular, should be able to provide information on the Alien's abduction methodology, but nothing further is heard from her.
    • You never find out what happens to the gassed people that you saved by completing an abduction mission. Same for the people trapped in the alien stasis tanks and surgery tables.
    • Considering all the peculiarities of the Outsiders (they're beings of Pure Energy with a biology completely unlike any other alien, likely have a different origin, and are crucial to entering the alien base), you would expect them to have an important role in the game's plot, but after the skeleton key has been built, it is never seen or mentioned again.
    • The EXALT supreme leader doesn't even show up in the game, has no model, and isn't there when you blow up his base. Neither the sequel nor The Bureau provides any clues.
  • What the Hell, Player? Dr. Vahlen gets pretty pissed off if you repeatedly capture aliens without an Alien Containment Facility to house them in. She also gets annoyed if you keep killing Outsiders instead of stunning them, regardless of whether you've already successfully captured one.
  • You Have Researched Breathing: Your supposedly elite soldiers need promotions just to acquire basic abilities that any real life soldier fresh out of basic training has, such as the ability to carry multiple grenades or use a first aid kit more than once in a mission. The use of suppressing fire to prevent an enemy from maneuvering or returning fire is one of the fundamentals of infantry tactics, but only two classes of XCOM soldiers are capable of doing this, and those classes must gain multiple promotions first.
    • In Enemy Within, one of the "superhuman" gene mods you can install into your soldiers is depth perception.
  • You Lose at Zero Trust: Nations have a Panic Meter that goes from 1 to 5. When it hits 5, they are in grave danger of pulling their funding from the XCOM project by the end of the month (if you fail a Terror mission in their country or incorrectly accuse them of harboring EXALT HQ in Enemy Within, they pull funding immediately, even if they have less than 5 panic), as they decide to redirect their funding to keep their own people under control. You lose the game when you lose eight nations total (half of the founding nations, in other words), regardless of the panic levels in the other nations, as the Council of Nations decides that the project is a failure. This will happen a whole lot more often on harder difficulties.
  • You Require More Vespene Gas: You've got four basic resource types in this game:
    • Money, the Gold equivalent. It's used for pretty much everything. You get awarded by the Council on a monthly basis based on which nations have satellite coverage, as well as for some Abduction missions, Council missions and requests. You can also sell scavenged alien materials on the Grey Market if you're strapped for cash.
    • Alien Alloys, Weapon Fragments, Elerium and various specialty items like UFO computers, power sources, and occasionally dead bodies, the Lumber equivalents. These are all used for the research and manufacture of advanced tech, but you can only get them by scavenging after missions. Enemy Within adds "Meld", which can be collected during missions and is used for Genetic Mods and MEC Troopers. Meld is collected from canisters that degrade over time, so they need to be collected quickly lest they expire. Killing Mechtoids and Heavy Floaters also provides a small amount of Meld.
    • Power is actually the Population equivalent, despite its name. All the facilities in your base need power to run, which is provided by constructable Generators. You can't build a facility if it requires more power than is available, but there is no other penalty to having insufficient Power, making it more of a cap on how many facilities you can have at the same time. Power demand also cannot exceed its supply under normal circumstancesnote  and existing facilities continue working at full efficiency even if you manage to do so.
    • Engineers and Scientists are a different kind of Population from Power, and serve as another hard cap. This is especially true with Engineers, as each project and facility have a certain minimum number of Engineers on staff requirement to construct and operate them. Some facilities, like the Generators mentioned above, have a scaling requirement where each facility built requires a higher minimum number of Engineers than the one before it. New Engineers and Scientists are provided monthly from member nations, with some giving more than others, and can also be granted as rewards for certain requests and missions.
  • Zerg Rush: Surprisingly, not usually used by the aliens, but by the human EXALT. Their fanaticism and superior numbers means that when they want an objective, many members will dash out into the open to get there faster, knowing that you can't kill them all before they start flanking your guys.
  • Zombie Apocalypse:
    • Chryssalids can easily cause one if left unchecked during Terror missions, due to those 18 tasty civilians running around.
    • " Site Recon" in Enemy Within takes place in the aftermath of one. A fishing village has been completely overtaken by zombies (and the Chryssalids that made them). At the end of the mission, the whole town is flattened by an airstrike.


"Good luck, Commander. And remember, we will be watching."

Alternative Title(s): X Com Enemy Within

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