History VideoGame / HalfLife

--> "How could one man have slipped through [[FacelessGoons your forces']] fingers time and time again? How is it possible? This is not some agent provocateur or highly trained assassin we are discussing. Gordon Freeman is a theoretical physicist who had hardly earned the distinction of his PhD at the time of the Black Mesa Incident. I have good reason to believe that in the intervening years, he was in a state that precluded further development of covert skills. The man you have consistently failed to slow, let alone capture, is by all standards simply that -- ''an ordinary man''."

** The teleporter relay built by the Resistance in ''Half-Life 2 is'' exclusively made to transport people between devices at two fixed points. The Combine, who never managed to figure out intradimensional teleportation on their own, end up copying this design to create a relay between Nova Prospekt and the Citadel.

* AllDesertsHaveCacti: The original ''VideoGame/HalfLife'' has a few saguaro cacti in the outdoor areas... despite being located in New Mexico. (While New Mexico has cacti, it ''doesn't'' have saguaros.)

* AnchoredTeleportation: Both the first and second games demonstrate that a successful jump is more guaranteed if there's a beacon on the other side.
** ''VideoGame/HalfLife1'': The main game and its expansion packs establish that is less chance of [[FateWorseThanDeath falling forever into an infinite alien dimension]] or [[TeleFrag getting instagibbed by a faulty teleporter into a dimension of flashing lights]] if there's a working teleport beacon, human or alien.
** ''VideoGame/HalfLife2'': Much of the plot happens because the attempted jump to a resistance base instead dumps the protagonist in random places before sticking him outside the rebel outpost and in the crosshairs of the fascist alien government currently hunting him, forcing him to take the long way to the resistance base.

* DoubleMeaningTitle: ''Blue Shift'' is a physics term, its protagonist is Barney Calhoun, a security guard in blue uniform on shift.

** Half-Life itself refers to the [[https://en.wikipedia.org/wiki/Half-life#In_biology_and_pharmacology scientific term]], and potentially the situation and theming for most enemies encountered, where many are slaves to a larger force (Vortigaunts, Zombie victims, Civil Protection, citizens of the Combine, etc.) or have had so much of their biology replaced with cybernetics that they're barely alive anymore (Combine troops, Striders, Stalkers, etc.).

In addition, there's ''VideoGame/CounterStrike'', which started out as a mod of the first ''Half-Life''. It was originally billed as part of the Half-Life series (and implicitly in the same universe due to shared assets like Black Mesa scientists and containers), with the 1.6 version of the mod being officially named ''Half-Life: Counter-Strike'' when sold at retail, and its remake, ''Counter-Strike: Source'' being bundled with every retail copy of ''Half-Life 2'', as well as, initially, every digital copy. Later iterations of the series (starting with ''Condition Zero'', and continuing with the standalone release of ''Counter-Strike: Source'' a year after it was released bundled with ''Half-Life 2'') were sold standalone and [[DivergentCharacterEvolution the series as a whole went a separate way]] from ''Half-Life'', with the first game remaining the only solid connection (it and its remake are still sold as part of ''Half-Life'' bundles on Steam, unlike the later ''Counter-Strike'' games).

* ''VideoGame/HalfLifeAlyx''[[labelnote:''*'']]VR prequel to ''Half-Life 2''[[/labelnote]] (2020)

In addition, there's ''VideoGame/CounterStrike'', which started out as a mod of the first ''Half-Life''. It was originally billed as part of the Half-Life series (and implicitly in the same universe due to shared assets like Black Mesa scientists and containers), with the 1.6 version of the mod being officially named ''Half-Life: Counter-Strike'' when sold at retail, and its remake, ''Counter-Strike: Source'' being bundled with every retail copy of ''Half-Life 2'', as well as, initially, every digital copy. Later iterations of the series (starting with ''Condition Zero'', and continued with the standalone release of ''Counter-Strike: Source'' a year after it was released bundled with ''Half-Life 2'') were sold standalone and [[DivergentCharacterEvolution the series as a whole went a separate way]] from ''Half-Life'', with the first game remaining the only solid connection (it and its remake are still sold as part of ''Half-Life'' bundles on Steam, unlike the later ''Counter-Strike'' games).

* AbandonedHospital: One of the settings in Episode One, which appears to have been taken over by the Combine. The impending city-sized explosion left it in the process of being abandoned ''again''

** The Gravity Gun easily invokes this trope, given that you can pick up and launch almost anything with it. When supercharged by dark energy, it can even pick up people, which kills them instantly.

* AlienSky: Xen has one, it looks like a vast greenish nebula which enshrouds the entire realm. This is especially so in the remake, Black Mesa, where it's depicted as blue-purple void of stars in the outer regions, and changes to a more red-orange hue on the central island, complete with a swirling vortex of energy for a sun
* AlienLandmass: Xen, the final level of the game, is a surreal alien landscape with floating, oddly-shaped landmasses and wonky physics that make it difficult to navigate.

* AllThereInTheManual: Averted, as part of the series' unique storytelling strategy. Despite you having been missing and in stasis for several years between parts 1 and 2, at no point does anyone explain to you what the hell happened during that time, nor does Gordon ever ask to be filled in. Unless you look at every newspaper clipping along the way, you can complete the entire game without any knowledge of the "Seven Hour War" or of what the Combine really is. Also, the only character that gives any real exposition is very easy to miss if you don't know where to look for him. If you have a lot of free time and possess an insane measure of dedication, you can construct a reasonably coherent picture.
* AlternateCharacterInterpretation - ''In-universe''. While it's implied quite a few Marines are having second thoughts of shooting civilians to cover-up the Black Mesa incident, everyone in the HECU wants a piece of Gordon Freeman - scuttlebutt had him killing a few Marines in cold blood, not to mention they believe him to be the one responsible for the whole mess (and not just the guy who pushed the crystal in). [[spoiler:Given that G-Man, the one who did initiate the resonance cascade, later hires Freeman as his elite agent, they aren't that far off. It's just that Gordon is an unwilling (as far as we can tell) agent of the G-Man.]]
* AmbiguousRobots: Pretty much everything you fight in the ''Half-Life 2'' series (less headcrabs, zombies and antlions) is ambiguously cyborg in nature. The flying synths and the Striders are probably the most ambiguously robotic.

** The shadowy Hazardous Environment Combat Unit who serves under the US military and who, thanks to their orders to kill the personnel of Black Mesa, is one of the main threats in ''Half-Life''.
** HECU gets their own Army in the even more shadowy Black Ops unit, who apparently goes even higher in command. Like the HECU, they're also there to stop the alien infestation after the HECU fails, with predictable results.

* ArtificialStupidity: Especially true of the HECU marines, who, despite showing off some pretty sophisticated AI behavior for the time, will break instantly as soon as there's more than one player, since it was heavily dependent on rigid scripting. Furthermore, while they are programmed to place grenades on the ground to cover their retreats, you can shoot them in the act, breaking that bit of programming and causing them to shoot back instead, instantly forgetting all about the armed grenade there is ''right beneath their own feet''.
** HECU marines will also lay down laser trip mines on occasion to block off routes for the player. However, sometimes they'll place one in the only exit out of an area they're in and will run right into their own trip mines to search for the player if they cannot attack the player from their current position.

** The HECU also had a hilarious habit of mixing up their reactions to grenades. When a Marine shouts to his comrades he's throwing or putting down a grenade, they normally crouch and cover their head, while he runs away from the grenade. Sometimes they get confused, and the Marine will put down the grenade at his feet, then crouch beside it and cover his head, and of course be blown to bits. Easy kill.
** Friendly [=NPCs=] in [=HL1=] and Opposing Force both had a tendency to shoot you if you happened to be between them and an enemy.

* {{Autodoc}}: Both first aid stations, which heal you, and similar looking HEV stations, which recharge your HEV suit.

* BadassBookworm: Gordon, duh. Dr. Breen himself is perplexed, and had this to say on the matter:
--> "How could one man have slipped through [[FacelessGoons your]] forces' fingers time and time again? How is it possible? This is not some agent provocateur or highly trained assassin we are discussing. Gordon Freeman is a theoretical physicist who had hardly earned the distinction of his Ph.D. at the time of the Black Mesa Incident. I have good reason to believe that in the intervening years, he was in a state that precluded further development of covert skills. The man you have consistently failed to slow, let alone capture, is by all standards simply that -- ''an ordinary man''."
* BadassNormal: While Freeman, Shepard, Green and Cross have special powered armor suits, Barney Calhoun was able to survive the Black Mesa incident and even traveling to Xen only wearing a common helmet and kevlar vest equipment. Extra points for Alyx for having no special protection at all and being able to fight alongside Gordon.

** Gordon would find random burnt corpses, or the disfigured bodies of what used to be those who were taken in by Civil Protection.

* BondVillainStupidity: Two marines, instead of dragging you to your interrogation and execution, toss you into a trash compactor. Filled with crates. And another crowbar sitting at the top. One of the missions cut from ''Decay'' was to retroactively avert this trope: a scene was planned involving the two marines executing Gordon before throwing his dead body into the compactor, unless they were promptly stopped by the player.

** The first game began and ended in a tram. Also interesting is that this seems to slightly carry over to the next game, where the player starts off in a train and also ends the game on a train, albeit the G-Man's metaphysical one. ''Episode One'' also ends with Gordon on a train, and ''Episode Two'' starts with you on a ''crashed'' train.

* BoringButPractical: In the first game, the most useful weapon was probably the humble Glock 17, the first gun you found, due to its common ammo and its amazing accuracy. It's almost a game breaker because no enemy can touch you at the range you can hit them with the pistol. The second game had the [=MP7=], which was really useful for dispatching Civil Protection officers and Antlions. It's fairly inaccurate and weak, but ammo is literally everywhere and it fires extremely fast. It becomes next to useless after you get your hands on the (also boring but practical) [=AR2=] and SPAS-12, though.

** A similar example, though with not as many years between: If you try to talk to security guards (the basis of the character Barney Calhoun) before the resonance cascade, one of their random lines is, "Hey, catch me later, I'll buy you a beer." In ''Half-Life 2'', Barney's first line upon revealing his identity to Gordon is, "About that beer I owed ya."

** The major WhamLine in ''Episode Two'', which is even more obscure because [[spoiler:the words are the name of a level in the first game, that only appears as a caption and never spoken by anyone]].

* CavalryBetrayal: The scientists and guards Gordon comes across in the first few hours after the resonance cascade will enthusiastically tell you that the US military have called in via radio and told that a team is under way to Black Mesa to kill the aliens and rescue the personnel of the facility. While the first part of the message is true, the team's orders have been changed (or always were) to terminate the personnel because of their status as witnesses.

** The G-Man will save people and provide them with information, but also interfere with their plan to move them into situations where [[UnwittingPawn everything they will do for their own gain will also advance his own plan]]. He isn't even trying to hide it.

** Only direct contact with radioactive waste causes any issues. Fair enough for Gordon, who has the HEV suit (designed for that sort of thing), not valid for the few times [=NPCs=] also get near it unless it's stabilized.

* CosmicHorrorStory: As the games progress, one can't help but get this vibe with the series. Especially with the presence of the Combine, a force that comes off as some never ending horror series of atrocity after atrocity. Then there's the appearance of hostile alien species like the Headcrabs and Antlions, and the later games have started to increasingly emphasize that [[HumanoidAbomination the G-Man]] is essentially '''[[Franchise/CthulhuMythos Nyarlathotep]]''' in all but name.
* CrapsackWorld: The poor Earth has been reduced to this state after the Resonance Cascade's Portal Storms, the Seven Hour War, and resulting Combine occupation. Even if the Lambda Resistance ''does'' save humanity from the Combine, mankind will likely be spending the next few centuries (if not millennia) just fighting to survive against the Antlions and all other alien monstrosities that have claimed their environmentally devastated homeworld for their own without any more miracles on par with Gordon Freeman's return. Ironically, the Combine seemed to be doing a pretty good job staving off those monstrosities, making them something of a collective LoadBearingBoss.

* CriticalExistenceFailure: Justified in that the suit has built in medical tech and movement assisting features. Even when the reactive armour is inactive, the suit can absorb damage that should otherwise cripple or even kill the wearer, while the suit's medical systems administer medicine (refilled from health containers or stations) to take care of whatever manages to leak through. This is evidenced in-game by the manner in which the suit responds to the damage Gordon takes, such as applying morphine to dull the pain of a bone-breaking jump.

** The G-Man ''might'' be this, or more of a HumanoidAbomination. And that's even assuming what we see of him ''is'' his real form!

** In ''Episode Two'', in order to get the "Little Rocket Man" achievement, you must "escort" (or rather carry, since it's just an item) a ''garden gnome'' from the first level '''all the way to nearly the end of the game'''. It's easy enough to fling it around for the start of the game, but it takes a lot of work to jam that thing in the car and keep it in place while you're dodging fire from a Hunter Chopper.

* EvilVersusEvil: In the first game, in some chapters (such as ''On A Rail'' and ''Questionable Ethics''), you could see HECU Marines gunning down Vortigaunts and Alien Grunts. For the most part they do a pretty good job, though they turn on you once the aliens are dead. In the second game, you can often find Combine soldiers fighting zombies and antlions. Once again, they do a pretty good job, but noticeably less so once Freeman destroys the Citadel and cut off the soldiers from their leadership.

** The main game already had plenty of hints of this. In "Questionable Ethics" you find several Xen creatures contained in laboratories. While on Xen yourself, you come across dozens of corpses wearing [=HEV=] suits. WordOfGod has also said that the sample Gordon pushes into the anti-mass spectrometer in the beginning of the game is the same kind of crystal that protects Nihilanth.

* ExtremeOmnivore: Barnacles, which attach themselves to ceilings and hang their tongue down to grab prey. They only eat human [=NPCs=] in the original game but from Half-Life 2 onward, they attempt to eat ''anything'' they grab, be it living, dead or inanimate, rather than only humans. Key word "attempt", as they only actually eat living [=NPC=] but spit back out everything else - the latter of which, strangely enough, includes corpses that got killed just a few seconds beforehand. If it's living, though, they'll eat ''anything'' whole regardless of size, up to and including Dog (who is a robot) and ''Striders'' (which are partially organic but ''far'' bigger than the volume of the barnacle's body). And yes, they eat the victim's uniform, combat gear and in the case of Combine soldiers, their cybernetic implants too, not just the fleshy bits.

** On the other hand, their "eat first, figure out if it's edible later" behavior means they can be easily distracted by throwing a barrel or crate at their tongue - or even better, an explosive barrel which can be detonated by gunfire before the barnacle drops it to wipe out entire groups of them at once. A later Source engine version update patched them so that each barnacle grabs each physics object only once then [[ArtificialBrilliance ignores it from that point on once having confirmed that it's not edible]], even if the player deliberately tries to feed it to them, so they can't be distracted indefinitely.

* FakeUltimateMook: The two tanks you encounter in ''Half-Life'' are dangerous and can instantly kill you if they are able to land a hit. However, they are immobile and if you can avoid the extremely slow-moving turret (which can't make a full 360 degree turn), you can destroy them at your leisure. The first tank doesn't even have a machine gun.
** The two Bradleys are a bit more dangerous, since their turret can actually swivel all the way around, but the first one still counts for this trope, as it oddly doesn't use its main gun, only firing missiles at you. These can be dodged and even [[GoodBadBugs redirected back at it]]. The second one, which actually uses its main gun, is much more dangerous, but it is still immobile.
* FanRemake: The much anticipated ''VideoGame/BlackMesa'' mod, which is meant to recreate ''Half-Life'' in the Source engine, and is made with Valve's blessing. The development has been a ''[[{{Vaporware}} long]]'' process, but as of September 14, 2012 it has finally been released.

* FastKillingRadiation: Throughout the series, being near or inside radiation/slime pits will trigger a warning message from Gordon's [[PoweredArmor HEV Suit]] and his health will start lowering until he gets out of the area. This is also present in the FanRemake of ''VideoGame/HalfLife1 1'' called ''VideoGame/BlackMesa'', which adds [[InterfaceScrew an interference effect to the HUD]] in order to emphasize the damage done.

* FloorboardFailure: Happens quite often. Also happens in ducts as well (once into a room full of laser tripwire explosives).

** In several of the battles with Antlion Guards, normal antlions back them up. In 2 of these battles, they continue to spawn: In ''Episode One'' they keep coming until you block the holes in the ground, and in ''Episode Two'' double guard battle they don't stop spawning until after the Guards are killed. In the latter circumstance, you have a powerful ally Vort who can easily dispatch the normal Antlions for you, allowing you to focus on the boss.
** The Gene Worm will periodically spawn Shock Troopers. Fortunately, this reveals its weak spot under its belly. Apply rocket launcher 3-4 times.

* {{Foreshadowing}}: In the tram ride of Half Life 1, the announcer says "More lives than your own may depend on your physical fitness."

* GaidenGame: ''VideoGame/{{Portal}}'' and ''Half-Life: VideoGame/CounterStrike''. The latter spawned its own separate series (and a remake), while the former started out as a separate series that, unlike the later ''Counter-Strike'' games (which don't seem to be in-continuity), still gives lip-service to its ''Half-Life'' universe setting.

* TheGreatestStoryNeverTold: Subverted. Half-way through the original game, US Marines special forces arrive, [[WhatTheHellHero with the intent of killing everyone]] and covering up the whole event. At the end of ''Opposing Force'' we find out the military [[ItsTheOnlyWayToBeSure detonated a nuke which destroyed the facility]]. Unfortunately, this caused the portal storms, the Seven Hour War and the Combine occupation, and Gordon Freeman, [[CantStopTheSignal instead of a story never told]], was elevated to messianic status as "The One Free Man."
* GuideDangIt: For players that are used to using guns to kill enemies rather than physics, many will feel this when encountering a Hunter for the first time. They can take a ridiculous amount of damage from bullets and explosions, but have a crippling weakness to physics objects. This is made worse by the fact that the only other enemy that is really weak to physics is the regular headcrab zombie, and only to [[OneHitKO sawblades]].
* GunsDoNotWorkThatWay: A recurring theme in the Half-Life series is the SPAS-12's secondary fire somehow acting as a duel-fire, despite the weapon only having one barrel. Presumably, Valve just assumed that the SPAS-12's magazine tube is a second barrel.

* HealThyself: the insta-heal medkits and medical stations.
* HeelRaceTurn: All that's known about the Vortigants in the first is that they're invading aliens. In the second game it's revealed that they were confused and enthralled, and are now grateful for the destruction of their puppet leader. By the third, they gather en mass to support Gordon specifically.

* HoldTheLine: Several examples, usually with easily-knocked over turrets.

* HumansAreWarriors: Subtly invoked throughout the series; the HECU grunts will commonly trounce Xen forces when pitted against them in AI battles and their weapons are far more precise and deadly to the player, the Combine expend more than a little effort to turn most able-bodied humans into cyborg troops for use in their interstellar conquests, and lest we forget, one untrained human scientist in a suit of ''really good body armor'' was able to fight his way through two separate armies at once, one of them a multi-species invasion force from another dimension, the other a hardened special forces branch of the US Marines, who were tracking his every move via GPS no less. And after that, Freeman's presence and violent resistance on Combine-occupied Earth for a few ''days'' was enough to incite mass armed rebellion at their base of operations, ''level the Citadel and most of City 17,'' and guarantee the success of the plan to neutralize the Combine's capacity for off-world reinforcement. On the flip side, Earth was entirely defeated by the Combine in a mere 7 hours of open warfare, but it is worth remembering that the Combine came from another universe, which they had already conquered and subjugated in its entirety, and them versus a single planet is hardly going to be a fair fight. When all is said and done, humanity is far from helpless against the various alien war machines present in the series.
* IconicItem: Gordon's crowbar becomes this in-universe between the events of ''Half-Life'' and ''Half-Life 2'' by the Vortiguants, who grant Gordon a messianic status as liberator and destroyer of their oppressor. His crowbar is thus a holy item, and depicted as such in numerous drawings.

* InformedAbility: The most technical things super-scientist Gordon Freeman has ever done are pushing a sample on a cart and plugging a teleporter in. Half-Life 2 explicitly refers to this fact. Early in the game Gordon has to plug in a cable and throw a switch, and Barney mentions that his MIT education is really paying off. It has been pointed out that the only bit of physics that Gordon ever seems to apply is F=ma. That is to say, he knows how to swing a crowbar ''really'' hard... that is until the advent of the Havoc physics engine, where Gordon now understands simple machines like levers and pulleys. According to the backstory, Gordon's [=PhD=] dissertation was a very complicated piece of work done on complex portal physics. Supposedly Gordon was given menial labor because he was young and was the new hire. Had the experiment worked Gordon almost certainly would have spent dozen of hours studying the results, running complex equations, organizing the data, and coming up with conclusions with a group of his peers. Later in Half Life 2, Eli is very eager to get Gordon out of his hazard suit and back into a lab coat. On both occasions, Gordon was forced into fight and flight due to an attack that occurred immediately afterwards.

* InsurmountableWaistHeightFence: Particularly in ''Half-Life 2'', where, to demonstrate the physics engine, you must stack things to climb said fences. In addition, the first game often had locked doors blocking your way - you had to destroy or find alternate routes which deviate into God-knows-where (such as abandoned areas of the facility or the other side of that dam).

** Gordon, an ordinary scientist caught up in the Black Mesa incident, ends up becoming a more skilled fighter than any number of security guards, HECU troops, or highly augmented transhuman soldiers, and because of this the rest of humanity comes to view him as a savior. When it comes to undoing the Resonance Cascade and putting an end to the Combine occupation of Earth, much of the heavy lifting falls to him. It certainly helps that he's protected from grievous harm by his [[PoweredArmor HEV Suit]], and the fight against the Combine is firmly established as a group effort between him, the other surviving scientists from Black Mesa, and the greater Resistance, who are able to set off a wide-scale uprising after his temporary disappearance at Nova Prospekt (though it's still on him to lead the push to the Citadel once he returns).

** Barney, at the time of the Black Mesa incident, is the only security guard who is able to help Rosenberg and his crew prep the prototype teleporter to be used as an escape, as every other guard on their side of the facility is conveniently dead and the few other staff Rosenberg is able to enlist the help of outside of his main group get killed off rather quickly.
* IvyLeagueForEveryone: Justified in the first game being set in a top secret research facility. {{Lampshaded}} by an NPC in ''Episode One'' who can be overheard saying "Sometimes it seems like everyone is a Doctor but me."
* JumpJetPack: The HEV Suit has a long jump module that's effectively a big rocket attached to Gordon's back for crossing gaps his normal jump had no hope of reaching. Not used very much in the game and abandoned in the sequel.

** The monorails in the first game are made in really crude fashion. They don't have anything that would resemble wheels, they just hover above the rail. The cab type can function both as classic and suspended monorail yet it also doesn't have any device on its roof to hang onto the rail. The door is only on one side but there is no second rail for the other direction so it cannot possibly operate as your average streetcar.
** In the second game when you first arrive in City 17 not only is the passenger car ridiculously short, it also has door only on one side. The platforms are absurdly low and to cover the clearance there is a small stairway which the train is required to stop exactly so the door would be aligned with it. The platforms are also laughably short unable to serve any train of significant length. If you inspect the train closely, you'll find out it [[https://www.trainsingames.com/img/hl2/picoupling.jpg doesn't have any couplings]]. The [[https://www.trainsingames.com/img/hl2/pioutside.jpg locomotive]] is derived from the [[https://en.wikipedia.org/wiki/DR1_diesel_train DR1]] which isn't a locomotive but a self-propelled car of a DMU. Now if you turn your attention to the tracks - they are really poorly made. They're absurdly crooked, not even trying to imitate proper curves, switches connecting in weird angles which would make any train derail at the mere sight of them. Some of the tracks are just plain, flat 2D lines with some reflection thrown in there to hide it. The switches are arranged in a way that makes no sense, preventing any meaningful operation in the trainyard. There are also randomly scattered freight cars apparently only to get in your way and utterly destroy any remaining hope for this game's rail works to serve any purpose.

** There is a grid of wires hanging overhead which would like to pass off as catenary, but no actual traction mains are present except for the headspan construction[[note]]given the high value of copper, one can easily assume that the Combine took it[[/note]]. What is really problematic is that a bridge and some tunnels nearby are actually too low to allow such a wire to pass through under them, let alone with a second messenger wire above[[note]]as is standard on all railroads except trams[[/note]]. The construction of the headspan wires is odd, too, as there is no obvious way to attach any wire at all, and even if there were, the messenger wires at the edges would have to be mounted higher than the ones in the middle. Finally, clearance between the hypothetical wire and the cars is way too low to be realistic and the wires are bound by obstructive clamps that'd hack-off any pantograph which would dare to so much as approach them.
** The Razor Train [[{{pun}} fares]] even worse. It's extremely tall. There's really no loading gauge in the world it would fit in. Unless the Combine built a specific lines just for those, they're completely useless. The train seems to be freight in nature but judging by its single-axled [[https://en.wikipedia.org/wiki/Jacobs_bogie Jacobs bogies]] it's apparently a multiple unit which are known to consist of fixed amount of permanently cupled cars which would be totally impractical for a freight train. They also seem to be very limited to what kind of cargo they can haul.
** After getting out of the mines you'll meet the only flat car in the game, which turns out to be much wider than the loading gauge would allow. Also many of the box cars bogies exceed the edges of the cars which makes is impossible to couple them. Not that there are any couplers on them in the first place.

* LateToTheTragedy: ''Half-Life'' was the first game to subvert this, as the first level is a leisurely stroll through the player's workplace, before all Hell breaks loose. (Ironically, with all of the [=NPCs=] telling Gordon, "You're late!") Played straight in ''Half-Life 2'', though, as Gordon is abruptly dropped into City 17 more than a decade after Earth's subjugation by the Combine, and played with - but ultimately straight - in ''Opposing Force'': Adrian is part of the first HECU responders, but his Osprey is taken out. He regains consciousness just as the military begins its pullout.

* LivingMotionDetector: The blind tentacles in the first game, and the canceled hydra for the second, somewhat brought back via scripts.

* LovecraftLite: The aliens take obvious inspiration from the ''Literature/CthulhuMythos'' in aesthetic, and the experiments and investigations that the Black Mesa personnel perform in an attempt to harvest knowledge (only to end up devoured and nearly bringing about the end of the world) would also be a familiar sight in Lovecraft's works. The Nihilanth, the Gonarch, and the Gene Worm in particular would fit pretty well alongside the pantheon of Great Old Ones. However, unlike the protagonists of the Mythos who were usually unprepared civilians in the 1920s/1930s, ''Half-Life'' stars a BadassBookworm with PoweredArmor and copious amounts of modern heavy weaponry. When you have a [[PhotoprotoneutronTorpedo backpack-mounted]] [[Film/{{Ghostbusters|1984}} nuclear accelerator]] or an anti-tank missile launcher, [[DidYouJustPunchOutCthulhu who needs a steamboat?]]

** The computer voice in ''Half-Life'': Deathmatch. The HECU would speak like this when in-battle with you.

** Same goes for Gunships, which are using a similar autocannon model.
** The Strider you encounter at the end of ''Episode One'' downplays this, firing at twice the fire rate than ones you fought previously.

* {{Nerf}}: The ''Source'' version of the original Half-Life, even on hard mode, has a lot less enemies to deal with in the Xen levels (and some other rare cases outside Xen) due to there not being as many walkover game-play triggers that spawn in new enemies; especially Alien Controllers. The "Interloper" level in particular really toned down on the triggers.

** Any overly excited person playing "Blue Shift" can accidentally (or purposefully) shoot the guard in the armory window in the crotch which the auto-aim automatically locks onto, or purposefully attack anyone else once you've receive your gun. This will result in Barney being fired for "improper handling of a Firearm." however there is a slight delay with the display and the game actually ending which gives you time to empty 1 or 2 clips of ammo into anyone you like.
* NoodleIncident: It's never explained exactly what the experiment at the beginning that causes the resonance cascade was ostensibly ''supposed'' to do. The second game implies Dr. Breen and the other higher ups knew full well it would cause the resonance cascade, but it's pretty obvious Freeman and the other scientists had no knowledge of this.

** One of the chapters in the original ''Half-Life'' forces Gordon to go through a waste processing factory. Yes, it's flesh-burning acid, but fortunately, Gordon's wearing the partially acid-proof [=HEV=] suit. Similarly, Adrian Shephard in the expansion has to go through some sort of experimental blast furnace, which has no rails or catwalks to shield workers, and is only accessible via a hole on the wall.
** Then there's the ''massive toxic spill'' you can see on the opening tram ride... In fact, the whole facility is a disaster waiting to happen: there are no emergency exits directly leading to the surface in case of fire or extradimensional incursions, ceilings and catwalks collapse without warning, and an alarmingly large amount of objects, namely computers, are MadeOfExplodium.
** One of the worst is a giant fan near the silo area. The ''only'' way to turn it on is by climbing down a ladder onto a narrow catwalk beneath the blades and pressing a button. The catch is that the fan blades touch the area anyone climbing the ladder up would be, so in order to survive the task, you have to press the button and then haul ass and hope the fan doesn't catch you on the way out.

** There's also the fact that literally everything is apparently structurally comprised, from solid concrete ceilings and walls to steel catwalks. Even most of the elevators don't work. Pretty much the only things in the entire Black Mesa facility that are able to withstand any sort of damage whatsoever are the exit doors, ''and they're all locked''. The abandoned areas (the cliff face and the old missile silo) have the excuse of no longer being maintained, but for some areas there really is no excuse. There is no reason that the two generators that run the tram to the surface should be allowed to launch giant arcs of electricity everywhere.

* PainfullySlowProjectile: The crossbow bolts move about a fast as a thrown baseball. This is likely to make up for the crossbow being so powerful, as well as being usable underwater.

* PlotPoweredStamina: Gordon never has to stop to eat, sleep, or take a piss (though one might forgive that as a function of the suit). While he did get a break in between the original game and ''Half-Life 2'', in which the G-Man probably started him at optimal health, he's on the go from then on with only brief moments of unconsciousness at the start of each installment. It isn't as if time isn't passing either; the sun starts setting as Gordon arrives at Black Mesa East, Ravenholm takes place at night, and the sun is just rising as Gordon emerges from the mines. When he arrives at the Vortigaunt Camp at the end of "Sandtraps", the sun is setting again, and at the end of "Nova Prospekt", despite a week passing in relative terms, Gordon still hasn't had any rest. The finale appears to take place shortly before sunset, so even if all you count is the original ''Half-Life 2'', Gordon is up and moving constantly for over forty-eight hours without a break.

** Specifically averted with Barney Calhoun in Blue shift. Your armour is probably about as strong as the power armour, and despite coming across some HEV suit chargers here and there, you can't use them and can only renew your armour by picking up "undamaged" armour from other, less fortunate guards.

* ReflectingLaser: The Tau Cannon / "Gauss". Technically a "hypervelocity projectile" weapon, but works like an insta-hit laser that reflects off any solid map surface at 45 degrees angle or less to the horizontal.

* RocketJump: Can be done with various explosives.

** The original game, ''Blue Shift'', and ''Opposing Force'' has a Satchel Charge as one of the weapons acquired mid-game. Pressing the alternate fire button has the player character shove the explosive on the ground, allowing it slide to a safe distance. The primary fire button, meanwhile, triggers the charge to blow.

** The premise of the first game of a military-funded experiment opening a portal to another dimension that envelops a settlement in mysterious storm that causes aliens to teleport in, followed by a heavy-handed military response, is inspired by ''Literature/TheMist''. Some of the Xen aliens also bear similarities to the monster designs described in that story. The game actually had the working title ''Quiver'', named after the Arrowhead military base from ''The Mist''.

** ''Opposing Force'' starts with a tutorial set during boot camp, paying homage to ''Film/FullMetalJacket'' boot camp sequences. Here's a scene-by scene comparison of the tutorial and the movie. Notably:

** In ''Opposing Force'', during the pit worm chapter, there is a panel with buttons on it. The buttons are labeled "Valve" and "Gearbox."
** The Displacer Cannon in ''Opposing Force'' is nearly identical to the BFG-9000 in ''VideoGame/{{Doom}}''. ''Doom'' and its sequels were also cited by several of the first game's designers as inspirations for ''Half-Life'' in a more general sense.
** The Gluon Gun from the first game is an unlicensed nuclear accelerator that uses uranium as ammunition. Not only is its appearance and operation very similar to that of the proton packs from ''Film/{{Ghostbusters|1984}}'', the name of the weapon in the game files is "weapon_egon", and several other files in the game refer to it as "the Egon Gun." Also, one of the soldiers' lines in ''Opposing Force'' upon being asked to follow you is "Sure, we can do more damage that way."
** The elevator in Unforeseen Consequences in the [[VideoGame/HalfLife1 first game]] is modeled almost exactly off of the one in ''{{Manga/Akira}}''. The two expansions that feature this same elevator even acknowledge this (at least, Gearbox does) in that the brush is named "akira_elev". The sewer area with the collapsed catwalk is also modeled after a similar area in one of the pages as well. Brett Johnson, one of the level designers, also admitted he modeled the areas as a shout-out.

** Not really a positive shout-out, but during the Antlion defense portion early in ''Episode Two'', Griggs mentions that he [[UsefulNotes/GeorgeWBush "misunderestimated"]] the size of the Antlion force.
** The premise of the first game and its overall structure are quite similar to ''VideoGame/{{Doom}}'' and several developers admitted to taking inspiration from it.

** Ted Backman in ''Raising the Bar'' admitted to modeling the Combine Advisors on the Guild Navigators from ''Literature/{{Dune}}''.

* SoftWater: Which saves you from massive damage ''a lot''. The engine demonstrates this trope ''aggressively'': custom maps use ankle-deep water to break several story falls all the time. Just don't jump into any water infested with parasites or that has broken electronics nearby, or it's instant death!

* SpaceMarine: Averted with the [=HECU=], which don't even have any specialized equipment, save for the PCV powered vest ''some'' soldiers are assigned.

* SuspiciousVideoGameGenerosity: Whenever this series drops you into a room stocked with ammo, armor and health packs you have reason to worry. Perhaps justified. With G-Man's ability to teleport any where and his chess master behavior, he could very well be the one leaving some of this caches at strategic areas for the protagonists to find.
* SwissArmyWeapon: Gordon Freeman's suit. Not only does it protect from dangerous hazards, it can block bullets, generate air, it has a flashlight, it can [[HyperSpaceArsenal hold many weapons]], allows Gordon to run faster, and has a scope.

* TorturedMonster: The zombies are humans who have been turned into PeoplePuppets and mutated by the parasitoid headcrabs attached to their heads. In the second game they can be heard screaming for help as they attack you.

** Headcrab zombies from the second game count, until you play their speech files [[https://www.youtube.com/watch?v=dxbd-Cg50Nk backwards]]. Then you wish they were unintelligible. In the first game, they'd simple gurgle at you.

* UnusableEnemyEquipment: Mostly averted. In trying to be immersive, the vast majority of weapons used by the enemies can also be used by the player, including mounted weapons, [[LivingWeapon alien weapons]], and [[BreadEggsBreadedEggs mounted alien weapons]]. However, items like the Sniper Rifle used by the HECU and Combine are unusable, and unique weapons like Alyx's pistol and Grigori's rifle are also unsuable.

* VideogameSetpiece: The games and expansions made heavy use of setpieces -- everything from monsters breaking down doors to automated tours of labyrinthine factories. Valve once said that they use so many because ''Half-Life'' without set pieces is boring; they themselves learned this lesson while brainstorming on the level design, sticking every single character, object and set piece they'd come up with so far into a single level and noticing how fun said level was to play. Such is the quality of their set pieces.

** A live wire dangling from the ceiling just zapped some headcrabs who were very close to a vent, after zapping the faceplate off that same vent. Where are you supposed to go in order to avoid going under the wire? Into said vent, of course!

** In the original game, a pair of {{mooks}} capture the player character and, rather than [[WhyDontYaJustShootHim just shooting him]], toss him in a trash compactor. Which he then escapes via conveniently stacked up garbage.

** ''Half-Life 2'' has a section in Nova Prospekt with a corridor of Combine Walls that close on each other and will crush you unless you find a way out.

* WeirdWorldWeirdFood: Post-Black Mesa incident, a lack of conventional food sources means that headcrabs and Xen leeches have become the main diet for anyone not living under the Combine.

** [[invoked]] Remember Adrian Shephard? The protagonist in Half-Life: Opposing Force? What happened to that guy? If we believe Gabe Newell, Valve is itching to get him into the main storyline, but he still has yet to be seen. Amusingly, in ''VideoGame/{{Portal}}'', there's an EasterEgg in which all keyboards have the letters A,S,H,P, and D colored yellow, referencing the [[FunWithAcronyms Aperture Science Handheld Portal Device]]. When someone inside Valve realized that it looked like 'Adrian Shephard', they decided [[ThrowItIn it'd be funny to have every letter that makes up 'Adrian Shephard' be yellow.]]
** Race X (the alien race from the Opposing Force expansion) is occasionally wondered about, but according to [[WordOfGod Marc Laidlaw]], they don't matter to the [=Half-Life=] Universe. Gearbox invented them to primarily experiment for future games of their own, and the minute Gearbox stopped making [=Half-Life=] games, [[DroppedABridgeOnHim they vanished]]. This is justified by the fact that they were only at Black Mesa by chance on account of all the trans-dimensional shenanigans going on. It's probable that their world was sealed off from ours following Shephard's victory over the Gene Worm, effectively putting a stop to their interactions with humanity.

** Used again in ''Episode Two'' by Kleiner when observing a eight-and-a-half pound weight difference in the rocket they're planning to launch. [[spoiler:It's Kleiner's pet headcrab, Lamarr. And a garden gnome, if you did the achievement.]]

*** Continuing the tradition, they only latch to standard Overwatch Soldiers once they're out of Combine control. Metrocops and Combine Elites are perfectly safe. May be justified as higher ranked Combine achieve that rank by submitting to further cybernetic augmentation; there may not be enough human left for the Headcrabs to consider them proper hosts.
* ZombieApocalypse: [[{{Reconstruction}} Reconstructed]]. In ''Half-Life'', zombies are created by alien crabs latching onto peoples' heads and taking control of the person's nervous system. The person effectively dies in the process, but remains animate because all the vitals that are necessary to live are in the crab, not the corpse. They're also still self-aware, just not in control.
** Practically, this is what happened to nearly every single place after the Black Mesa Incident allowed headcrabs onto Earth and Combine started to use headcrab shells. There is no area in Half-Life 2 and its episodes where there would be no headcrab zombies or headcrabs wandering in search for a victim. The most direct example of this trope is Ravenholm, a town which was housing the refugees from City 17 before it was subjected to massive bombardment of headcrab shells and turned into Hell on Earth [[BadassPreacher with a single survivor doing the work of saving the lost souls]] by the time Gordon shows up.

** It's revealed in Opposing Force that [[spoiler: the scientists have been experimenting with Xen life for long enough to have a terrarium and have modified a Barnacle to use as a weapon.]]

%% * GettingCrapPastThe Radar: Due to overwhelming and persistent misuse, GCPTR is on-page examples only until 01 June 2021. If you are reading this in the future, please check the trope page to make sure your example fits the current definition.

** Dr. Judith Mossmann calls to mind the biblical Judith, [[spoiler: whose [[FakeDefector Fake Defection]] helped to (literally) decapitate the Assyrian army.]]

* TheReveal: [[spoiler: Black Mesa knew about Xen for years, maybe decades, and were studying and ''processing'' the denizens.]]

* StupidityIsTheOnlyOption: Even if you know about [[spoiler: the ambush in "Apprehension"]] from playing before or reading spoilers you have no choice but to walk into it. Somewhat Justified as [[FourthWallMyopia Gordon himself would have no way of knowing about it ahead of time.]]

* SurprisinglyHappyEnding: [[spoiler: Considering that most games in the series ends with a cliffhanger, Blue Shift's ending comes across as this: after some trouble with the teleporter, Barney and Rosenberg manage to escape Black Mesa with no strings attached.]]

** Used again in ''Episode Two'' by Kleiner when observing a eight-and-a-half pound weight difference in the rocket they're planning to launch. [[spoiler: It's Kleiner's pet headcrab, Lamarr. And a garden gnome, if you did the achievement.]]

** ''[[UpdatedRerelease Half-Life Deathmatch: Source]]'' (2006)[[index]]

** ''Half-Life 2: Deathmatch'' (2004)
** ''Half-Life 2: Lost Coast'' (2005)

** In ''Opposing Force'', two are mentioned from ''Film/StarWars''. First, a security guard asks a scientist if he has seen the new IG-88. Second, [[https://www.youtube.com/watch?v=uHU8tU2DbGI&feature=related at the end of this segment, you see doors that look like they were from the trash compactor room]] in ''Film/ANewHope''.

%%* TakeYourTime

** You travel to an alien factory. Of ''course'' the BigBad's near.

** Locked in a room with a pit that has giant whirling fan blades the size of a bus and a ceiling that's boarded over. What to do? Jump out over the fan blades [[strike:and turn into chunky salsa]] to get blown upwards, naturally!

%%* SortingAlgorithmOfEvil