History YMMV / XComEnemyUnknown

** Floaters: unlike the original game, many players actually hate them now. Their jetpacks mean they'll almost always find exactly the right spot to land in where your entire team is flanked and they're safely behind cover. Heavy Floaters are TheSameButMore: more firepower (regular plasma rifle, and a grenade to make things worse), more mobility, more aiming accuracy, and more hit points.

** The Thin Men are pretty popular as well, a result of combining cool design, creepy animations and [[FaceDeathWithDignity a very memorable interrogation scene.]]

** ''Enemy Within'' gives us "Site Recon", which tasks you with exploring an abandoned fishing village that has gone silent after an alleged alien attack. It turns out that [[spoiler: the entire town was overrun by Chryssalids [[ZombieApocalypse and is now infested by Chryssalid zombies]]]]. But wait, [[FromBadToWorse it gets better]]. [[spoiler: The source of the infestation is a fishing ship ''with a whale carcass that the Chryssalids are using as a hive'']]. Understandably, Central decides that [[spoiler:[[ScrewThisImOuttaHere this entire town can fuck right off]] and [[ItsTheOnlyWayToBeSure calls for an airstrike to purge the area]]]]. From there, you have ''eight turns'' to make it back to the opposite corner of the map for extraction [[spoiler: ''while fleeing from an endless wave of Chryssalids spawning from the hive'']]. Unless you can cleverly strategize and get a few lucky rolls, you'll probably lose people, either from [[spoiler: the Chryssalids]] or from simply being left behind. Though if you get this mission late enough, it can turn into cakewalk instead, since no enemy unit can shoot you, Archangel armor can make you practically invincible here. Having a squadsight sniper with Archangel Armor means that they can easily kill any enemies that dare move into his/her line of fire. Power-armored assault troops and well-upgraded MEC troopers can also slaughter the Chryssalids by the dozen in the late game.

* ThatOneAchievement: "A Continental Fellow", which requires you to beat the game from each of the five starting continents. To call this particular achievement time-consuming would be a ''major'' understatement, considering that a single playthrough can last you well over 50 hours depending on your difficulty and success. The game also provides no way to track which continents you have already completed the game with, so make sure you write down your progress somewhere, otherwise you run the risk of repeating yourself.

** Dr. Vahlen, due to her actions and thinking well reflecting that of many XCOM players. While she may get excited at the sight of new technologies, she does show empathy for the soldiers and fear for humanity. She still does whatever it takes to get the info she needs out of captive aliens and they tend to "expire" quickly. From their perspective she must be some mythical demon and the reason why you DON'T want to get caught alive by those creepy humans with their stun guns.

* AntiClimaxBoss: The final boss, while not the same joke the one in the original games was (which couldn't attack and could be killed before even entering the room it was in), can be taken down in just a few hits if you bring enough snipers. Woe betide the player who incautiously moves their troops into Rift range and fails to kill him, though - he (and his goons) are more than capable of dishing out a TotalPartyKill if you let him.

** The most anticlimactic thing about it is simply how ''underwhelming'' it is. You're expecting the leader of the invasion to be some kind of epic, impressive, grandiose alien overlord, and what do you find at the end of the Temple Ship? [[spoiler:An Ethereal completely indistiguishable from the ones you've been killing for the last few hours of the game apart from a slightly more ornate helmet and a ton more HP- basically nothing more than a KingMook.]] Even the Alien Brain from the original game, helpless as it was, was ''unique.'' "Disappointing" is putting it ''lightly.''

** The Reinforced Armor trait on Sectopods in Enemy Within. This trait ''halves'' all incoming damage, meaning that it essentially has ''sixty hitpoints''. The only exception to this is the MEC's Electro Pulse attack, which does a full five damage and stuns. If none of your squad has Shredder Rockets or Heat Ammo, your best strategy is to stick your head between your legs and kiss your ass goodbye. After the first encounter, it's never a bad idea to go on a non-abduction mission expecting a miniboss.
** Overwatch is normally a useful ability, but one alien is capable of triggering multiple overwatches at the same time. This means that your soldiers can fire a disproportionate amount of ammo into a single alien, possibly resulting in other aliens being able to move unhindered. This was fixed for the sequel, where overwatch moves are now sequential, and a GameMod that retrofits sequential overwatch into ''EU/EW'' is among the most popular mods out there.
** Control is completely locked out when it's the aliens' turn. Upon realizing a mistake save-scumming players hate having to wait to load from a more desirable point.

** "Portent" is the first real difficulty spike in ''Enemy Within''. It happens within only two months after the start of the game and if the game didn't introduce the Thin Men before, they will now. Everything about this map seems tailored to the Thin Men's advantage. High ground to boost their accuracy to insane levels, close groups which means you will more likely trigger two or more groups at a time, and your troopers measly health will more likely wiped out in a single shot on Classic or Impossible. This mission is responsible for most early rage quits on Classic or Impossible.
** The second special Council mission, "Confounding Light", from the ''Slingshot'' {{DLC}}. You have only ''ten turns'' to find and activate four beacons, all of which are heavily guarded by poisonous Thin Men, who start receiving hard-hitting Muton reinforcements (who pack full-sized Plasma Rifles instead of the Light ones they normally have early on) after a while. Putting it off until your soldiers have some better equipment is advisable.

** The player's first Terror mission, bonus points if it's their first play through too. It comes early enough in the game where you might not have a lot of upgrades, and is the first time you encounter Chryssalids. That's bad enough, but there's tons of civilians scattered across the map, who are being killed by said Chryssalids, if the player doesn't kill the Chyrssalids and any Zombies fast enough, they'll get swamped as the number of enemies multiply.

* NarmCharm: When you first reveal an alien or EXALT pod, the game plays one of a selection of sounds straight out of a SciFi BMovie from TheFifites. It's cheesy, but it pairs up great with the combat tunes that flare up simultaneously.

** After researching Xenobiology, a cutscene would play in which Vahlen explains the mechanism of the Arc Thrower: going into close range and stunning the alien. Bradford reacts to this with a bewildered utterance of "Close range?!". Fast forward to ''VideoGame/XCOM2'', and the Ranger class not only uses shotguns, but also a blade that they can use in melee. And even more hilariously, in the "Alien Hunters" DLC pack, Bradford is a Ranger himself while in the field.

** A sniper with Double Tap, Squadsight, and a Plasma Sniper Rifle is going to pretty much slaughter the opposition, especially if they have the [[GeoEffects high ground]]. In The Zone is also pretty broken, especially when you consider that enemies in flight or unable to take cover are valid kills for In The Zone to trigger. A pretty great way to get the high ground is via the Archangel Armor: stay back, pick a good sightline, fly up high enough that the sniper has elevated ground aim bonus against everything else, and Squadsight will do the rest as long as there's an ally to spot for the sniper. A properly equipped sniper can end up being a critical attack fiend and even possibly your squad leader due to racking up kills easily.[[labelnote:IMPORTANT NOTE]]Squadsight was nerfed in ''Enemy Within'' and no regular shots can crit ''at all''. The only way to land a Critical from Squadsight is by using Headshot.[[/labelnote]]
** With a Heavy to clear the aliens' cover and lower their health, an ITZ Sniper can kill all opposition, and still have a turn to spare. Sure, it's wasted experience, but sometimes you gotta

** MEC Troopers. Even with their basic starting loadout these guys have a [[GatlingGood huge minigun]] that will rip apart most enemies, and their starting MEC gives more health than any of the armor worn by normal soldiers except for the Archangel and Titan Armor, and the only normal armor that gives higher defense is the Ghost Armor. Though the MEC Troopers can't use cover, the Kinetic Strike Module system lets them OneHitKill anything short of a Cyberdisk or Mechtoid (and if upgraded, only Berserkers, Mechtoids, Sectopods and Ethereals can survive a hit from it), and its Flamethrower is easily among the best AreaOfEffect attacks in the game, that causes ''all'' organic units to panic if it doesn't kill them. All this before getting any of the MEC upgrades or class abilities, which in the late game can make a single well-used MEC almost unstoppable.

** Pretty much all of the Hero Units, though this is [[PurposelyOverpowered deliberate]].

** At least in ''Enemy Within'', Floaters can now get themselves stuck on terrain, and waste both their moves trying to escape, leaving them sitting ducks for your soldiers.
** Spontaneously, the weapon camos in ''Enemy Within'' can bug out and leave you with the default camo.

** The [[{{BFG}} Alloy Cannon]] sound when you fire it. A deep resonating "''boom''" that is usually followed by the cries of agony of your target.
*** Also, the sound of a Blaster Launcher firing, and the warbling noise its projectile makes. Followed by the sound of something (possibly several somethings) violently leaving this plane of existence.
*** The sound of the Plasma Sniper Rifle firing. ''kaaaa...''-'''THUNK'''.

* ParanoiaFuel: Seekers. Once they show up in a mission, you've pretty much got to ''drop everything'' and put your entire squad into Overwatch, because they're out there, hunting you, and if you drop your guard for even a heartbeat, one of your soldiers is getting strangled.
* PortingDisaster: ''Enemy Unknown Plus'' on the Vita suffers from a massive amount of issues. Loading can take up to three minutes from startup to actually playing the game, and load times are still pretty long once you actually start playing. There are plenty of graphical glitches, which occasionally include not showing where a character's movement becomes dashing and the smoke from smoke grenades becoming invisible. The framerate also stutters every now and again. Using any item in a soldier's inventory when they're in cover has a chance of them clipping into it and being stuck and unable to move, even with explosives destroying the thing they were stuck on. And lastly, even if you do manage to get through everything, it has a tendency to crash later on in the game!
** It should be noted that this is after the rather unpopular mobile phone port (despite having Enemy Unknown and Enemy Within released separately) for the same reasons, although the loading time is slightly quicker due to lots of reductions and a far smaller level template is used for the mobile phone port.
* TheScrappy: Central Officer Bradford is not popular with some fans, probably because the first thing he does in game (at least, if the tutorial is activated) is command the very first XCOM squad to their death leaving only one survivor, and from then on seems to make it a point to act in complete GenreBlindness. He's also a rather generic crew-cut military man, with little characterisation, making him hard to like even disregarding his bad decisions.
** RescuedFromTheScrappyHeap: The "Security Breach" trailer from ''Enemy Within'' has changed this, though, simply because Bradford is shown beating the crap out of [[spoiler: a mind controlled base technician]].
*** If you fail the mission where [[spoiler:the aliens attack XCOM HQ]], a cutscene plays showing Bradford's dead body propped up against the wall and with a pistol at his side. Lying in front of him is a dead Sectoid. [[TakingYouWithMe The implications are profound]].

** The second special Council mission, "Confounding Light", from the ''Slingshot'' {{DLC}}. You have only ''ten turns'' to find and activate four beacons, all of which are heavily guarded by poisonous Thin Men, who start receiving hard hitting Muton reinforcements (who pack full-sized Plasma Rifles instead of the Light ones they normally have early on) after a while. Putting it off until your soldiers have some better equipment is advisable.

* AscendedMeme: Vahlen's infamous request to avoid the use of explosives where possible was turned into around 5 and a half minutes of scenes of explosives-use and the corresponding request, [[https://www.youtube.com/watch?v=nzm9P4LK62E with 1 minute of that]] as a StupidStatementDanceMix (and a single "Close range?"), on a stream, looped for 24 hours. It also received multiple humorous references in [[VideoGame/XCOM2 the sequel]], such as [[https://www.youtube.com/watch?v=iA0nIRE4u2o an official remix]].
* AuthorsSavingThrow: Was this for 2K after the disastrous announcement of the "prequel" 1950's XCOM reboot. While the idea for a traditional strategy in line with the original series was being toyed with behind the scenes, the only game getting attention was the FPS, which was scathingly criticized for having little in common with the series on appearance. While the prequel soon began hitting development roadblocks (including a shift from first person to third among others), the strategy game finally was announced despite being far from finished, earning kudos. Eventually, thanks to encouraged innovations from weekly challenges, the game began to develop into what would be the final game. When the TPS prequel, now known as ''[[Videogame/TheBureauXComDeclassified The Bureau]]'' exited its development hell a year later, further criticism for that game were alleviated by the announcement of ''Enemy Within'', who's trailers impressed.

** [=SHIVs=]. There's three mechanics that make [=SHIVs=] exceptionally overpowered: you don't have to pay for their weapons, they get increasingly cheaper from every workshop connection (being completely free at 8 workshops), and in Enemy Within they get continuous healing up until they're critically hit.

* FunnyAneurysmMoment: During the alien base assault, you find a device that Dr. Shen thinks is what the aliens use for entertainment, then he remarks "At least they're not playing computer games." [[spoiler: Then in XCOM 2, it's revealed that the reason why the Aliens easily defeated mankind is because the Commander was captured by them very early into the invasion and held them captive in a simulation. It is all but outright said that the events of Enemy Unknown/Enemy Within's campaign was that simulation, and the Commander unknowingly fed the knowledge and tactics they used in there to the Aliens, who then used it to great effect in their invasion.]]

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* EightPointEight: 8.2 from IGN, igniting a massive backlash from dedicated fans. Metacritic gives it a solid-ish 89/100, brought down by ''one'' 70% review. Even ''[[WebAnimation/ZeroPunctuation Yahtzee]]'' liked the game enough to include it on his top five for 2012.

* CreepyAwesome: Some of the more unsettling aliens, like the [[BigCreepyCrawlies Chryssalids]] and [[UncannyValley Thin]] [[StiffUpperLip Men]].

*** [[https://twitter.com/steveogdenart/status/1126508070236897282 Evidently whoever was charge of designing the official project badge noticed the similarity too.]]

* EightPointEight: 8.2 from IGN, igniting a massive backlash from dedicated fans. Metacritic gives it a solid-ish 89/100, brought down by ''one'' 70% review. Even ''[[WebAnimation/ZeroPunctuation Yahtzee]]'' liked the game enough to include it on his top five for 2012.

** Abduction missions. See TheyChangedItNowItSucks, below.

* TheyChangedItNowItSucks: In [[VideoGame/XComUFODefense X-COM,]] beyond the earliest stage of the game your team's power was limited only by the player's competence. You were capable of building multiple bases, and manning them with enough soldiers and aircraft to handle anything the aliens could throw at you. In this game you only have one base and one Skyranger, and [[ScrappyMechanic the game rubs your face in it]] by periodically [[SadisticChoice throwing multiple missions at you at once and only allowing you to pick one of them,]] while the aliens automatically overrun the other site [[ButThouMust and there's nothing you can do about it.]] This forced incompetence built into the design of the game has alienated many fans of the original.

** Covering Fire. It allows reaction shots (such as while using suppression or on overwatch) to trigger on enemy ''attacks'' in addition to on enemy movement like normal. It sure ''sounds'' useful... until you realize that if your oveerwatch shot triggered because of an enemy ''firing'' rather than them ''moving'' , then that means that you could already see and potentially shoot them on the turn you put that soldier on overwatch in the first place. And if the soldier had had a decent chance of hitting that enemy, you would've simply instructed them to do so then and there. [[DownplayedTrope The ability does]], however, become useful when combined with suppression, as it means that your support is more likely to get a bonus shot in when suppressing a dangerous enemy.

** Suppression. When used, the soldier expends twice as much ammo as on a normal shot to use suppressing fire on the targeted enemy. For the following round, said enemy then has significant aim penalties, and the suppressing soldier gets a reaction shot if the enemy moves. Problem is, it's an ability for the Heavy, who gets the biggest guns in the game, and thus if you're up against an opponent dangerous enough to warrant suppressing in the first place, your heavy will generally be more useful simply shooting-to-kill. [[DownplayedTrope That said]] it can also be used by supports, who are not a damage-oriented class, and it also works on either class if you're trying to let a specific underleveled soldier get the killing blow or keep an enemy you're trying to capture with the arc thrower from running away.

** A sniper with Double Tap, Squad Sight, and a Plasma Sniper Rifle is going to pretty much slaughter the opposition, especially if they have the [[GeoEffects high ground]]. In The Zone is also pretty broken, but relies on your sniper being in position to flank everyone, or all enemies being out of cover.
*** A pretty great way to get the high ground is via the Archangel Armor (especially so with the Advanced Flight Foundry project). If you fly high enough with that you're simultaneously unlikely to be targeted while also being likely to be in a good position for squadshotting enemies and providing far-reaching overwatch. A properly equipped sniper can end up being a critical attack fiend and even possibly your squad leader due to racking up kills easily.
** With a Heavy to clear the aliens' cover and lower their health, an ITZ Sniper can kill all opposition, and still have a turn to spare.

** Operation Gangplank, the final mission of ''Slingshot''. You're on a Battleship, but unlike late-game Battleships, this one is mostly crewed by Sectoids and Thin Men, and they show up piecemeal. Sure, a Chryssalid, a Muton, and a Cyberdisc show up later on, but those are singular in every instance, and are nothing a good team with Carapace Armor and lasers can't handle, especially when compared with the ''Muton rush'' that was Confounding Light, the previous ''Slingshot'' mission.
** Furies, the final mission of ''Operation Progeny'', counts as well. The previous mission, Deluge, often had Mutons and Mechtoids pouring down on the level, all the while being timed. Though this mission is timed too, the only resistance one faces here are Thin Men and the occasional Berserker. The layout is the familiar Abductor ship level too, so there's no way to get lost either.

** If you're competent at rescuing civilians, Terror missions are a breather for the problem of global panic. These missions are not easy in the slightest, but if you manage to save a respectable number of civilians, panic will abate in the country of the terror attack as well as, to a lesser extent, ''in the entire continent''. It's especially important when panic is high on countries you already have satellite coverage over.
* BrokenBase: With a series like this, it was bound to happen. Most of the players can be split into 3 groups:

** Even Impossible is a gigantic leap up from Classic, with the aliens getting bonus health and accuracy/defense/crit chance. Sure, if you can beat Classic you know how to properly play, but now the Sectoids are too beefy to be killed by a single grenade, not to mention your soldiers are now frail enough to be killed by a single plasma bolt. Likewise, the Thin Men and Floaters are now also too tough for the Shredder Rocket to kill them anymore, although it will still soften them up for follow-up attacks.

** In the early game, the rush becomes to get as many satellites as possible up in the air, so that you can stop running out of credits. When you finally manage to do so, you quickly find out that ''you can no longer launch satellites to lower panic''. This can result in extremely tense moments, waiting for a Terror mission, or hoping that the next abduction doesn't include one of the countries already on the brink of panic.
*** This is a somewhat odd case, as satellite coverage also prevents abductions, so long as the satellites have been protecting the country since the start of the month. Thus the real danger from this comes in the time between when you start getting significant satellite coverage and when you get universal satellite coverage, usually a month or two later. It also depends on how far you've progressed in the game; if you have beaten the first alien base, it generally is easier to control panic levels.

** The level [[http://ufopaedia.org/index.php?title=StreetHurricane_(EU2012) "Street Hurricane"]] is referred to as "Murder Street" by some players because good cover is sparse, its linear design means there are few flanking opportunities, and the size of the map means activating multiple groups of enemies at once is quite likely. At least until you get Squadsight snipers on the roof of the bus stop, in which case the long distance and poor cover can work in your favor. Made even worse in Enemy Within where it can be a ''Terror Mission''.

* FunnyAneurysmMoment: During the alien base assault, you find a device that Dr. Shen thinks it's what the aliens use for entertainment, then he remarks "At least they're not playing computer games." [[spoiler: in XCOM 2, the reason why the Aliens are easy to subjugate humankind, is how the Commander is hooked to a strategic simulation machine, feeding tactics to the ADVENT foot soldiers as well as the aliens.]]