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Video Game / Half-Life

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A tense moment for Gordon Freeman, thirty seconds before blasting an alien's skull off.

Run. Think. Shoot. Live.

Half-Life, by developer team Valve and originally published by Sierra in its final years, is the first in the Half-Life series and follows a day in the life of physicist Gordon Freeman, a bearded, bespectacled Heroic Mime who works in the Anomalous Materials laboratory at the vast Black Mesa Research Facility, a top-secret complex in the middle of the New Mexico desert. While performing a test on a strange crystalline substance, Gordon accidentally initiates a 'resonance cascade' — an event which causes bizarre, violent creatures to be spontaneously transported from another dimension. Now Gordon must work his way across the base in pursuit of a way to close the dimensional rift, fighting off not only the acid-spewing, electricity-shooting, zombifying aliens but also the Hazardous Environment Combat Unit (HECU), a special unit under the US military, who have swarmed into the complex and are destroying the creatures and silencing the facility's personnel with equal vigor.


Notable for its total immersion of the player. The game is entirely played in first person and in real time, with very little sound not produced by actions in the game world, and no sounds at all made by the central character; also, there are few cutscenes (and even they let you look around during them) — the player has control of the character at all times, and the story unfolds entirely in-game.

The designers actually had great difficulty with the level design at first, and got stuck in a rut. In order to take stock, they created a single level containing every gimmick, enemy, and bit of level furniture that they had come up with for the game so far. Said level was fantastic, and they realized that this density of set pieces was the "certain something" the game lacked.

Gearbox Software made three official Expansion Packs for the original game, which act as POV Sequels for the main plot. They are as follows:

  • Opposing Force begins shortly after the Resonance Cascade, and has the player controlling Corporal Adrian Shephard, one of numerous US Marines sent as the initial clean-up team. Involved in a chopper crash and separated from his squadron, Shephard awakens as the Marines begin their evacuation. Notably fills in what happened in Black Mesa after Freeman takes the battle to Xen. Additionally, Shephard is the only protagonist whose fate still remains completely unknown.
  • Blue Shift runs concurrently with about the first third of the main plot, with the player controlling security guard Barney Calhoun. Working to evacuate the facility following the accident, Barney's story examines the outbreak from a survivors perspective; instead of combating the problem like Freeman, it's about getting out alive. The only expansion (presumed) to be canonical, as Barney later reappears as a significant supporting character in Half-Life 2 and its following episodes.
  • Decay follows two other Black Mesa scientists, Drs. Gina Cross and Colette Green, and is the only official co-operative entry to date. Following the doctors as they act as key scientists, their story shows the work of the Lambda scientists that Freeman co-operates with, explaining how they acted to undo the Resonance Cascade and Xen invasion. Developed and released exclusively for the PS2 version of Half-Life, it can also be played on the PC thanks to the efforts of the mod community.

Gearbox took some liberties towards the storylines, which still causes fan disputes to their canonicity; as Word of God by the series' main writer, Marc Laidlaw, has deemed them semi-canonical until further notice, some label them as Fanon Discontinuity, while others ferociously defend their being canonical — due in no small part to Adrian Shephard's status as an Ensemble Dark Horse.

The game engine was also famous for being highly customizable, leading to a long series of mods. Some of them were single-player, such as Gunman Chronicles and They Hunger,note  while famous multiplayer mods include Deathmatch Classic, Ricochet, Day of Defeat , Natural Selection, The Hidden , and Afraid of Monsters.note  Especially notable of all mods are Team Fortress and Counter-Strike, both of which have famously ascended to independent games in their own right (and adopted by Valve themselves); because of this, Half-Life and its mods are collectively one of the most influential games of all time.

A sequel, Half-Life 2, which would prove no less influential, was released in 2004. Half-Life and its multiplayer mode were ported to Half-Life 2's Source Engine as Half-Life: Source and Half-Life Deathmatch: Source, though were otherwise mostly unchanged.

In September 2012, Black Mesa, a comprehensive Fan Remake that recreates the entire game in the Source engine, was released, after over eight years of waiting.

In early 2013, with Valve's push to get Steam on Linux, they ported Half-Life 1 to Linux, as well as macOS.

If you enjoyed this game, or want to watch it instead of play it, do check out Freeman's Mind.

Half-Life contains examples of:

  • Action Girl: Drs. Gina Cross and Colette Green.
  • Action Survivor: Dr. Gordon Freeman and Barney Calhoun, the latter especially. Both men spend a lot of their time trying not to get killed by the aliens and the HECU forces but where as Gordon becomes an Action Hero, Barney's story is all about getting out of Black Mesa alive and not having to risk his life for extra reasons outside of his control.
  • Air-Vent Passageway: While the series as a whole is famous for it, one of the most memorable subversions happens in the original. You are forced to crawl through some air vents, but the Marines hear you and shoot the hell out of it. The entire vent falls off the ceiling and crashes to the ground with you inside, or if you backed up, trapped in another part of the vent with the Marines shooting the hell out of you, albeit with more cover.
  • Adjustable Censorship: You have the option to disable the blood and/or gore.
  • Animated Outtakes: The PS2 version had some Dummied Out voice lines like this with animations to go with them, put to video here.
  • Area 51: Black Mesa is basically a civilian-owned expy for this.
  • Artificial Brilliance:
    • Half-Life was widely praised for the A.I. of its human Marine enemies, who were the first FPS enemies to work in squads and use complex tactical behaviors and movement patterns instead of simply charging in a straight line at the player.
    • The cockroaches are also pretty impressively programmed for prop NPCs.
    • There's actually a channel by the name of Marphitimus Blackimus that catalogs the different interesting little facts and programming features of Half-Life and its spinoffs.
  • Artificial Stupidity: Grunts have a tendency towards friendly casualties when throwing grenades, and will forget about armed grenades they drop if they catch sight of the player. The player can also trick grunts into a killbox by lying in wait behind a corner. No matter how many of their fellow grunts are slaughtered, they will still charge blindly around corners.
    • The player can actually do that with every enemy if there's a corner for the player to hide behind, making the Vortigaunts and Houndeyes very easy to pick off.
    • Friendly NPCs have a tendency to get lost, stuck in rooms, refuse to follow you after a while and shoot you in the back. Opposing Force's HECU Marines in particular suffer from this quite badly at times, forcing you to double back if you need them.
  • Attack Its Weak Point: Gee, I wonder why a gaping hole with a glowing purple orb inside just opened up on that giant monster.
  • Awesome, but Impractical: The Gluon Gun can destroy any non-boss NPC in a second or so max. It also chews up all of your ammo in mere seconds.
  • Badass Army: The HECU. Made up of highly trained marines backed by a full repertoire of US military hardware. They're quite deadly, but unfortunately for them they're a single special forces battalion going up against an entire alien army (and Gordon Freeman). Things go well for them at first, but once the alien invasion really gets underway they're rather quickly overwhelmed and resort to pulling out of the facility altogether.
    • The Xen aliens get a mention too. They have a rather large number of easily killed mooks, but the elite of their army (alien grunts and gargantuas come to mind) are quite dangerous. Their 'aircraft' (another alien species) also seem to be a credible threat to fighter jets and helicopters (they were doing airdrops during Surface Tension, suggesting that the US military was unable to secure air superiority.)
    • Not to mention the Black Ops. Compared to the HECU, they have access to the same equipment, but are also far better trained and specialized. And they do a much better job at handling both the Xen and Race X invasions, managing to be on equal footing with them for a while longer. Like the HECU, however, they're eventually overwhelmed as well and resort to nuking the facility.
    • Race X's aliens. Their Shock Troopers are arguably tougher to take down than the Alien Grunts, and their Pit Worms and Gene Worms are shown to be just as tough, if not tougher, than the Gargantuas.
  • Bee Bee Gun: The Hornet Gun.
  • BFG: The Displacer from Opposing Force is very obviously inspired by the trope namer.
  • Bookends: The game begins and ends in a tram. Opposing Force matches this by beginning and ending in a military transport aircraft.
    • Also, you go down an AKIRA-esque lift at the end of Unforseen Consequences (the first chapter after the Resonance Cascade), and then down a similar one at the beginning of Lambda Core (the last chapter to take place at Black Mesa).
  • Bootstrapped Theme: Hazardous Environments is the music from the logo for Valve Software.
  • Boring, but Practical: The Hivehand, the only weapon you have that regenerates ammo. It's especially useful once you get to Xen, where ammo is very scarce overall.
  • Boss Arena Idiocy: If the Nihilanth didn't have those gigantic stalagmites in his lair to hide behind it would be pretty much impossible to avoid his attacks (his main attack is lock-on and does massive damage)
  • Boss Battle:
  • Boss in Mook Clothing: Voltigores in Opposing Force.
  • Captain Obvious: In Opposing Force's training level, Shephard gets shot point-blank with a shotgun to demonstrate the effectiveness of the PCV armor vest.
  • Continuity Nod:
    • On the initial train journey, you pass by a security guard banging on a door; in Blue Shift, where you play as a security guard, the first door you come to malfunctions, and if you look around while waiting for the guard on the other side to open it, you'll see Freeman passing you by. Later on, you can overhear some marines complaining about having to do the crap work because Shephard's team hasn't arrived yet.
    • Opposing Force is full of them, being an Interquel, starting from the opening chopper ride (where you see the mountain pass Freeman navigates) to actually seeing Freeman enter the Xen portal!
  • Couldn't Find a Pen: There are some numbers written in blood near a scientist's corpse in the chapter Lambda Core. These numbers are a hint for an upcoming puzzle.
  • Creator Cameo:
    • Gabe Newell's office can be seen in the chapter "Office Complex".
    • In "Pit Worm's Lair" where you have to press a button to eliminate a boss, you need to first enable a valve and a gearbox.
    • In "Captive Freight" when you're traveling through the tunnels before reaching the train-yard, you will come across an opened box that just so happens to have gear shaped objects spilling onto the floor. Aka, a gearbox.
    • In the fifth chapter of Opposing Force there are two scientists lying dead near their desks, which carry the nametags "S. Reardon" and "S. Jones", referencing Gearbox Software developers Sean Reardon and Steven Jones.
  • Creepy Cockroach: Black Mesa has no shortage of them. As noted under Artificial Brilliance. the Roaches in the game have a surprising amount of AI built into them, which is impressive given that even modern games usually give them pre-scripted animations or simply render them as particle effects.
  • Creepy Monotone: The G-Man, the Black Mesa PA system, and the HECU marines' radio chatter. Funnily enough, the marines sound like normal human beings in Opposing Force, where they're your allies.
  • Curb Stomp Cushion: By the second day of the incident, the HECU is being steadily overwhelmed by the aliens, but as far as the player sees they tend to win the individual skirmishes. This suggests that the aliens are only winning because of superior numbers (a whole army vs a single special forces battalion) and that the marines are giving as good as they get. It's true that they're still enemies of the player (and everyone else in Black Mesa) but it's still easier to root for the humans during an alien invasion.
  • Cut-and-Paste Environments: Opposing Force has a rather odd case of this. When using the Displacement weapon, you can teleport to a random location somewhere in the Half-Life universe, and these locations are different any time you load into a new story map. However, after discovering about the first 5 or 6 maps, you come to realize that the later maps will reuse the previous locations with a slight variation on the items in the area. Basically, once you've used the Displacement Gun a certain amount of times, you've basically seen all the locations.
  • Cutting the Knot: The player can beat "On A Rail" the intended way, unlocking paths forward for the rail car and using it to progress... or the player can just foot it for most of the chapter and Sequence Break at several locations. The only places riding the tram are required is to destroy some concrete barriers, go up an elevator shaft, and pass through some electrified water.
  • Damn You, Muscle Memory!: "Jump" in the PS2 port is L1 by default; luckily, the schematic is remappable.
  • Daylight Horror: All but one of the outdoor scenes take place during the daytime. Most clearly demonstrated when Gordon has to dodge tentacles and headcrabs coming out of the sand.
  • Dead Character Walking: The original has this: if an NPC has scripted dialogue, but you kill them before they begin to speak, the corpse will speak anyway. The mouth moves and the audio can be heard, but otherwise he is dead. (This works at least on the security guard at the end of the Power Up sequence.)
  • Deus ex Nukina: Happens to Black Mesa at the end of Opposing Force..
  • Developers' Foresight:
    • In Blue Shift during the ''Captive Freight" level, you come across two scientists in your search for Dr. Rosenberg. If you actually try to backtrack with these two scientists following, you would come to realize that there is an invisible wall that will not allow the scientists to walk any further. That's because if you were able to backtrack far enough, you would come across the breakable wall that you would eventually learn about from Dr. Rosenberg that leads to where his colleagues are creating the portal device to escape Black Mesa. The reason for the invisible wall was so that you couldn't break the story and have two random scientists waiting at the elevator when Dr. Rosenberg leads you to it later on in the story.
    • Also in Blue Shift, if the player destroys the wall hiding the elevator to the portal chamber before Dr. Rosenberg leads you back to it, you will soon realize that he will have a different line-of-dialogue regarding the fact that Calhoun has already found the hidden elevator instead of the normal dialogue to destroy the wall.
    • The ammo belt feeding the M249 in Opposing Force is fully animated, being properly removed when reloading while there's still ammo and the belt actually running dry. This is as opposed to other games when the belt is infinitely long and mysteriously disappears when reloading. Most games, even modern ones, don't even do this.
    • One part of Opposing Force has Shephard finally catching up to Freeman and seeing him just as he jumps into the Xen portal (which the player does in the main game). Should the player manage to kill Freeman in the very small time window he is visible, the game grants a Non-Standard Game Over for breaking story canon:
    Subject attempted to create a temporal paradox.
    • The player can also follow Freeman through the portal, resulting in them coming out in the same area as Gordon, albeit several feet away and over a bottomless pit. There's just enough time for the player to catch another glimpse of Freeman (and maybe take a shot at him) before falling and getting the same Non-Standard Game Over as the previous example.
  • Donut Mess with a Security Guard: In Blue Shift, the fat security guard in the firing range is seen trying to reach for his holstered gun while holding a donut with the closer hand. Later, a scientist tells another guard "Shouldn't you be off guarding some coffee and donuts?"
  • Downer Ending: For Half-Life and Opposing Force, Gordon and Adrian are placed into stasis as some sort of mercenaries. It extends even farther - the Black Mesa incident attracted the Combine to Earth, completely enslaving it, and Adrian's dialogue with G-Man implies he'll be frozen for a very, very long time.
  • Dumb Jock: The graffiti the Marines leave on the walls to intimidate Gordon are full of misspellings.
  • Dumb, but Diligent: This trope seems to be encouraged by Black Mesa, with several signs throughout the facility saying "Work harder, not smarter." This even gets called out by Gordon Freeman in Freeman's Mind
    Gordon Freeman: "Yeah that's us, alright. We stay the course with stupid."
  • Early Installment Weirdness:
    • The general design of the game and its Expansions are much brighter colored than its sequel.
    • The Vortigaunts, due to the general lack of knowledge about Xen in this game, are called "Alien Slaves" in the game files, and talk in a stereotypically high-pitched, "alien" voice, as opposed to the monk-esque manner they do in the sequels.
    • Ally and enemy alike can explode into a bunch of body parts, which isn't as prominent in later installments.
    • The Alpha version of the game was intended to be very different. The art style was more campy and unrealistic, with characters having very exaggerated features like bug eyesnote . The level design was clearly more Quake-esque involving a darker and more unrealistic color palette and guns that are held at the center of the player's view. Gordon's role in the story was apparently different, with all Black Mesa staff originally being against him. Gordon himself was a large, biker-looking man with a huge beard. Dozens of enemies were cut from the game, some getting as far as to be modeled and scripted. Even the name was different, with the work-in-progress title of the project being Quiver, a reference to the Arrowhead Project from Stephen King's The Mist.
  • Earn Your Happy Ending: Blue Shift at least affords Barney a happy ending, though it's not easy.
  • Earth Is a Battlefield: In Opposing Force, when a third party, Race X, becomes involved.
  • Easter Egg: You can irritate VOX if you're particularly persistent.
    • One in Decay that was discovered only very recently. At the very start of the chapter/mission "Intensity", if you shoot the keypad before Dr. Richard Keller starts briefing the player(s, you get a short and humorous piece of dialogue.
    Dr. Keller: Good job for doing previous stuff. Now let's get ready to do new stuff.
  • Establishing Character Moment: Many of the enemies (as well as the HECU) get one.
  • Evil vs. Evil:
    • At multiple points you can encounter HECU marines battling Xen creatures, and wait around to take out the winner.
    • Same goes for the encounters between the Black Ops and Race X aliens later in the Black Mesa incident set in the Opposing Force expansion.
  • Explosive Instrumentation: Black Mesa's computers seem to be prone to this even before the resonance cascade.
  • Eye Beam: Pit Worm in Opposing Force shoots one from its sole eye. Players who Go for the Eye can cause it to flinch, but won't otherwise harm it.
  • Fluffy Tamer: Opposing Force has weaponized Barnacles.
  • Foreshadowing: One of the Nihilanth's quotes directly foreshadow the sequel with an early, implied mention of the Combine.
Their slaves... we are their slaves... we are...
  • Fragile Speedster: The female Black Ops Assassins have below average health, but are crazy fast, can make huge leaps, and on the highest difficulty setting, come equipped with a cloaking device. They're also Glass Cannons, and can easily wipe half your health away in groups.
  • From Bad to Worse: Dr. Freeman starts his day running late, gets trapped in the middle of an experiment Gone Horribly Wrong, has to escape from the creatures emerging from said experiment, then has to deal with the marines working on containment, THEN black-ops ninjas. Even after that it gets even worse for him and the rest of humanity.
  • Getting Crap Past the Radar:
    • The Gonarch toward the end of the game was literally conceived because someone in the studio suggested "putting a huge testicle on a set of spider legs". Its name is also blatantly a portmanteau of "gonads" and "monarch".
    • One of the cut monsters for the game was called "Mr. Friendly", a creature that would attempt to "rape the player to death" according to the behind-the-scenes book, Raising the Bar.
  • Go for the Eye: In Opposing Force, the Pit Worm can be briefly stunned this way, and the key to destroying the Gene Worm involves shooting its eyes repeatedly.
  • Gone Horribly Wrong: The experiment that let the aliens in.
  • Grappling-Hook Pistol: The detached barnacle in Opposing Force, but only to biological matter. It also doubles as a lethal weapon, heavily damaging organic enemies (or in the case of headcrabs, reeling them in and instakilling them).
  • Hand Cannon: The Python does far more damage than the .357 it's supposed to be, doing three times more damage than Opposing Force's M249, which fires rifle rounds that fairly realistically take down marines in full body armor after 3-5 hits.
  • Heal Thyself: The game follows the standard convention of instantly healing by picking up medkits. Unusually though, this actually appears to be canonical rather than a game mechanic. The syringes the scientist use to heal you (as well as the wall health kits in the PlayStation 2 port) have some weird green liquid in them that instantly heals all your wounds, and the medkits appear to contain the same substance. This may seem odd, but when you get to Xen, you encounter several pools of water that also magically heal you. The abundance of human corpses around Xen (as well as the location of an actual research outpost in Blue Shift) suggests that the technology for this was stolen from the aliens via these pools.
  • Hyperspace Arsenal: By the end of the first game, Gordon is carrying a crowbar, a 9mm handgun, a shotgun, a sub-machine gun, a revolver, grenades, an RPG, laser tripmines, a laser gun, a bigger laser gun, an alien gun with living bullets, satchel charges and snarks. Plus ammunition. The worst example is the Gluon Gun, which is a backpack mounted nuclear reactor.
    • Adrian Shephard of Opposing Force has a wrench, combat knife, desert eagle, a sniper rifle, M249 Machine Gun, the Displacement Gun, a weaponized Barnacle, Spore Launcher, and a Shock Roach. Plus with a certain cheat code, he can also equip all of Gordon's arsenal as listed above.
  • I Just Want to Be Badass: The first game was one of the first FPS games to avert this trope, and the game was remarkably atmospheric as a result. Ten years on, the atmosphere remains, but Gordon's taken a level in wish-fulfillment.
  • Indecisive Deconstruction: The first game can be read as a deconstruction of the Trope Codifier Doom. The basic premise (an experiment into teleportation technology goes horribly wrong) is basically the same as Doom. Like Doom, there is very little plot exposition. But unlike Doom, Half-Life showed you exactly how terrifying this kind of scenario would be if it happened in the real world; you must think and not act like a stereotypical Space Marine in order to remain alive. And of course, this kind of experiment would require immense levels of government funding. Necessitating a large covert laboratory. And thus, when everything goes wrong the military have to be called in to keep things covert. However, the developers have at no point implied any critical intent. Thus, Half-Life is arguably an unintentional deconstruction. Also, given how influential the first game was on all future shooters, the game seems like a played-straight example of the genre to someone raised on modern shooters.
    • It's also a reverse of Doom. You're playing a guy who just started his job and doing his job - his first real work he's done just happens to mark the end of the world as he knows it. And right when he think he's out of the chaos the rescuing marines are there to kill him. The security guards, which in Doom are possessed and attempt to kill you, are friendly and are just trying to survive.
  • Informed Ability: The most we ever see of Gordon Freeman actually being a physicist is when he pushes a cart into the anti-mass spectrometer. Barney lampshades this in the sequel.
  • Just Following Orders: Pretty much the extent Gordon had to do with the resonance cascade.
    • Then the marines who are called in to take out the scientists - then the black ops team who are called in to take out the marines.
  • Lightning Gun: The Shock Roach is a living version of this trope.
  • Living Weapon: The Spore Launcher, Shock Roach and Barnacle Grapple from Opposing Force. The Hivehand from the original game may count as well.
  • Loose Canon: Opposing Force and Blue Shift.
  • Manual Leader, AI Party: In Opposing Force, you're usually teamed up with a squad of AI marines which you can direct, and use to perform certain functions (but you can't directly play as one of them).
  • Mêlée à Trois: In total, there are five separate factions fighting each other in the Black Mesa incident. There's Gordon Freeman and Black Mesa security guards, the Xen aliens, the HECU marines, the Black Ops note , and Race X.
  • Militaries Are Useless: While the marines are pretty tough, and individually competent, the guy who gave them orders is probably very, very dumb. The lab accident engineered an inter-dimensional alien invasion? Let's kill the security guards to prevent them from doing their job! A particular scientist seems pretty good at killing loads of aliens for us? Let's devote all our resources to taking him down! Now because of all this mess we have plenty of witnesses to kill? Let's shoot them on sight instead of gathering them (and then shooting them)! And now our soldiers are being overwhelmed by the aliens that just keep coming? Let's send other soldiers to kill these soldiers! In the end, they evacuate and just nuke the complex to end the resonance cascade, leaving Freeman alone to go to the alien dimension and stop the invasion.
  • Monster Closet: The game explains it by way of the monsters getting into unused drywalled-off corridors due to random teleporting.
  • New Weapon Target Range: The crossbow is found in a shark cage that immediately drops you into the water with a big, swimming enemy, giving you the chance to learn that the crossbow is both the only weapon besides the pistol that works underwater, and it's also quite powerful.
  • No Indoor Voice: The HECU Marines, due to their voices always sounding like they're coming out of walkie talkies. Even lampshaded by one line they say while idle: "Squad, quiet down!" at the same not-very-quiet level.
  • No OSHA Compliance: Apparently Black Mesa was built by people to ensure no employee survives in even the smallest emergency.
  • Not So Stoic: The HEV suit computer is usually, well, mechanical, with no inflection on its words. But when Gordon is on the verge of death:
    HEV Suit: (Urgent tone) EMERGENCY! USER! DEATH! IMMINENT!!
  • Not So Different: Invoked by the G-Man towards Adrian Shephard.
    G-Man: I admit, I have a fascination with those who adopt and survive against all odds... they rather remind me of myself.
  • Planet Looters: Race X in Opposing Force.
  • Portal Network: Xen has one. Gordon uses it to navigate the place, as he often finds himself trapped inside small floating islands that can barely sustain a few animals (such as the first real island), or even "islands" that are just rocks that have just enough to stand on. Why they have one is a mystery however, as the aliens are repeatedly shown to be able to teleport wherever they want, even in groups, as a consequence of the Nihilanth's control.
  • The Precarious Ledge: During the "Surface Tension" section, you have to fight Marines along the side of a cliff face. It becomes extremely narrow in places and can be nerve-wracking for people with a fear of heights.
  • Press X to Die: In Opposing Force, you can get an electricity-firing weapon called the Shock Roach. You're fully capable of firing it underwater, despite the fact that doing so kills you immediately.
  • Punch-Packing Pistol: For some reason, the same 9mm cartridges do more damage when fired from the Glock than when fired from the MP5. Also, the Glock is given the miraculous ability to be fired underwaternote .
  • Puzzle Boss:
    • The Tentacles when you first encounter them in the main game, and the Pit Worm in Opposing Force. Both are defeated similarly, by activating the surrounding machinery, which also in both cases requires the player to sneak or run past the boss several times to reach the necessary switches.
    • The Gargantuas. Each one you encounter has some method to kill it using the environment. Technically, you can kill one with your weapons, but having maxed out ammunition for every weapon in your inventory is just barely enough firepower.
  • Secondary Fire: Several weapons featured this. Mostly they were simple things like a laser sight or a scope, but in some cases it basically made the weapon two guns in one, and in other FPS games of the time it would've been a separate weapon altogether rather than a secondary fire. It can be said that Half-Life 1 actually had 19 weapons instead of 15.
    • The SMG/assault rifle had an M203 grenade launcher mounted under that could hold ten grenades and never needed to be reloaded. This, combined with its reasonably common ammo, made it somewhat overpowered.
    • The shotgun could fire both barrels at the same time (even though it only has one barrel), giving you twice the damage at the cost of accuracy, ammo, and pump time. Very similar to the Super Shotgun weapon in Doom II.
    • The Tau Cannon's secondary fire was a powerful, charged, pixel-accurate laser beam that changed it from a rapid-fire infantry muncher to a single shot anti-vehicle weapon.
    • The Hivehand had two modes of fire: the primary fire launched heat-seeking "thornets" at a semi-automatic rate. The secondary function "dumb fired" all the thornets in quick succession; much faster than the primary fire, but without the homing ability.
  • Scenic Tour Level: The former Trope Namer. Gordon takes a tram in the original, Shephard takes a chopper ride with his squadron in Opposing Force, and Barney makes his way to an elevator while passing through security.
  • Sequence Breaking: In "Blast Pit," it's possible to save the scientist who would have been taken away by a Tentacle by quickly rushing over to him, and speaking to him; cancelling the scientist's scripted event.
  • Shark Tunnel: "Crush Depth" in Opposing Force, where a few of the lovely icythyosaurs have broken out of.
  • Sidekick: Barney the recurring security guard.
  • Slave Mooks: The Vortigaunts.
  • Split Screen: Decay's method of display.
  • Starfish Aliens: Most of the aliens barely resemble any form of Earth wildlife.
  • Stop Poking Me!: Walking into certain locked doors repeatedly in the first game will start to drive VOX crazy.
    • The same VOX can be poked fun at in the PC Mod of Decay's Hazardous Course chapter.
  • Teamwork Puzzle Game: Decay.
  • Tempting Fate: You can overhear one HECU trooper telling another that he killed a bunch of scientists and "not one of them fought back", and proceed to do exactly that.
  • Ten-Second Flashlight: Severely downplayed. While the torch does recharge faster than its juice is spent, it lasts for a really long time. Most of the time, you won't see the icon grow dim past the beam portion of it.
  • Title Drop: "Blue Shift" is the In-Universe name of the security shift that Barney works on.
  • Tracking Device: Apparently Freeman's HEV suit has one, and both the science team and the military have been using it to monitor his location and, in the latter's case, set up ambushes.
  • Two-Keyed Lock: The test chamber has to be unlocked by two scientists each activating retinal scanners.
  • Unbroken First-Person Perspective: The Trope Codifier for the use of this trope in a narrative context. As described above, the game unfolds entirely from the perspective of Gordon Freeman, with no cutscenes.
  • Unwinnable: Unlike its sequel, you won't get a Non-Standard Game Over if an essential NPC gets killed.
  • Vader Breath: The "Gonomes", the final evolution of the Headcrab Zombies, could easily be identified by a rattling noise.
  • Vengeful Vending Machine: Early in Opposing Force, Shephard encounters a fat security guard named Otis with his hand stuck in a vending machine. The guard curses, with lines like "Stupid machines!" and asks the player for a quarter. It's possible to operate the machine with the Use key, and this makes a candy bar pop out. However, the guard does nothing if you do so.
  • Video Game Cruelty Potential: With the exception of a few NPCs necessary to advance, nothing is stopping you from killing every scientist or guard you see as long as you have a weapon. Killing said NPCs results in a Non-Standard Game Over.
  • Visual Pun: In Opposing Force, to defeat the Pit Worm, you have to first reactivate a Gear Box, and open a pressure Valve. Hmm...
    • For a bonus, before activating the valve you have to use a Steam Vent. Since Opposing Force came out years before Steam, it's coincidental, but still pretty funny.
  • Weaponized Offspring: The Gonarch creates Headcrabs (who are essentially smaller versions of it) during the fight against it.
    • According to Word of God, the Spore Launcher from Opposing Force is an infant Shock Trooper.
  • What Happened to the Mouse?: Race X and poor Adrian Shephard. Marc Laidlaw has said that he doesn't want to develop further on Race X, saying that they were only experiments by Gearbox for future games, and that Gearbox would have developed them further if they were still doing expansions for Half-Life. He has also jokingly called Adrian a case of Schrödinger's cat, as he is in a state of being both canonical and non-canonical at the same time. His ultimate fate depends on what Valve want to do with him in the future. Gabe Newell has reportedly been wanting to incorporate him in the canon for some time.
  • What Measure Is a Mook?: Both Mook and One-Man Army are Deconstructed; sneaky players can listen in on the Army as they have weird self-hating conversations about slaughtering hundreds of scientists who expected them to RESCUE them - and later their rage at the player, who they believe was the mastermind behind the invasion and have been slaughtering their comrades wholesale. On the other hand, one of the Marines laments having none of the scientists fight back.
    • You play as a HECU marine in the Opposing Force expansion pack. While said Marine is comatose for most of the original game and wakes up just as the military begins pulling out, your allies are all trying to work together to pull out.
  • Why Don't Ya Just Shoot Him?: Double Subverted. Two marines who capture Freeman decide they should kill him instead of taking him in for questioning, in case he escapes and causes more trouble. But they don't shoot him; They just leave him in a trash compactor, still breathing.

Alternative Title(s): Blue Shift