[[quoteright:350:http://static.tvtropes.org/pmwiki/pub/images/DOOMpic.JPG]]
[[caption-width-right:350:"[[FunnyBackgroundEvent Hey, leave some for me!]]"]]
->"Over the centuries, mankind has tried many ways of combating the forces of evil... prayer, fasting, good works and so on. Up until ''Doom'', no one seemed to have thought about [[MugglesDoItBetter the double-barrel shotgun]]. Eat leaden death, demon..."
-->-- '''Creator/TerryPratchett'''

'''''Doom''''', Creator/IdSoftware's December 1993 follow-up to ''VideoGame/Wolfenstein3D'', was a big step forward in the art of texture mapping, and an even bigger step forward in video game violence. It follows the [[ExcusePlot story]] of an unnamed [[ASpaceMarineIsYou Space Marine]] posted to the Union Aerospace Corporation's base on Phobos, one of the moons of Mars. When teleportation experiments between Phobos and Deimos cause Deimos to vanish and a horde of grotesque monsters to invade the Phobos base, our hero is the only human left alive between the two bases. He fights his way through the creatures in search of a way off Phobos, finding himself transported instead to Deimos, now residing in the creatures' homeland, which turns out to be none other than Hell itself.

The release of ''Doom'' was met with unprecedented controversy regarding its content. Not only was there a very high amount of frank Satanic imagery (albeit all cast in a highly negative light), it was filled with graphic depictions of zombies and monsters being [[LudicrousGibs blown apart]], eviscerated, shot to pieces and generally [[MadeOfPlasticine disintegrating into piles of gore]]. Gameplay was extremely gung-ho -- the makers noted that the manual could have simply read, "If it moves, kill it" -- and encouraged the player to attack with reckless abandon, using such implements as chainsaws, chainguns and the [[TropeNamer original]] {{BFG}}, a massive weapon which could reduce an entire room of monsters to viscera. Even the player's own face, shown near the health counter as in ''Wolfenstein'', became battered and bloodied with damage.

Also, whereas ''Wolfenstein'''s fortresses all had identical lighting, ''Doom'' featured variable lighting, including flickering and glowing lights, adding to the game's atmosphere. The game also introduced vertical height, rather than the horizontal-only format of ''Wolfenstein''. The game also introduced the idea of multi-player [[CompetitiveMultiplayer death matches]] and [[CoOpMultiplayer co-op missions]] in a modern FPS, with its developers fully expecting ''Doom'' to be the biggest cause of decreased productivity in IT companies the world over in 1993. And [[GoneHorriblyRight they were right]].

Followed by '''''Doom II: Hell on Earth''''' (1994), which saw the demons invading Earth, which was a huge success. In between ''Doom II'' and ''3'', ''Final Doom'' was released the same month as ''VideoGame/{{Quake}}''. It was identical to ''Doom II'', but came with two different {{Expansion Pack}}s: ''TNT: Evilution'', created by the third party [[GameMod modding]] group [=TeamTNT=] (originally intended to be free until id struck a publishing deal with them;) and ''The Plutonia Experiment'', made by two members of the group in four months' time, generally considered the hardest of the official packs. (''Final Doom'' also included a 32-bit DirectX version of the Doom engine, making it the only way to play classic ''Doom'' on many modern 64-bit Windows machines, besides virtual machines like DOSBox or the many source ports.)

A decade later, '''''Doom 3''''' (2004) was released. The third installment, which was a reboot rather than a sequel, breaks with the first two significantly, with a dark, oppressive tone much more akin to a SurvivalHorror than anything. It was this incarnation on which the [[Film/{{Doom}} movie]] was based. This was followed by the expansion pack ''Resurrection of Evil'', set two years later. The game was remade in HD, compiling the first two games with it, in addition to adding another eight levels to its campaign. Furthermore, [[ScrappyMechanic you can actually wield a flashlight and a gun at the same time]]. This compilation, titled the ''BFG Edition'', was released in October 2012.

At Quake-Con 2014, id Software revealed '''''Doom''''', a reboot of the franchise, known to most fans as ''Doom 4''. To prevent any leaks, the only people who attended the convention were allowed to see gameplay of ''Doom''. Descriptions of the footage mentioned that Doomguy will be able to {{double|Jump}}-jump, and be able to perform {{finishing move}}s, such as [[BloodierAndGorier tearing an enemy's heart out]] [[DarkerAndEdgier then forcing them to eat it]], almost akin to ''VideoGame/BrutalDoom''. ''Doom'' used to be known as ''Doom 4'' when it was revealed in 2007, but the game went through TroubledProduction, so id decided to revive it.

''Doom'' has been ported to many many console systems over the years. The PlayStation and SegaSaturn versions combined levels from both ''Doom'' and ''Doom II'' alongside a large number of unique missions; more original levels were released in a sequel entitled ''Final Doom''. There was also ''Doom 64'' for the {{Nintendo 64}}, which was an entirely new entry in the series and probably more of a ''Doom 3'' than the actual ''Doom 3'' was (it was released years before, ran on a modified version of the original engine and continued the story of the first two games). ''Doom''[='=]s source code has been released, and, at this point, almost anything with a CPU in it -- many cameras and music players, some watches, several appliances, even a graphing calculator has been shown to run it for about half a minute before crashing -- has had a version of ''Doom'' released for it. The game used a creepy and distinctive [[DoomDoors sound effect for doors opening]], which has been re-used in many SpeculativeFiction series for all sorts of things.

Also, a [[Comicbook/{{Doom}} comic]] for ''Doom'' [[http://www.i-mockery.com/comics/longbox18/default.php was made]] at the height of the [[TheDarkAgeOfComicBooks dark age]]. It's hilarious, probably intentionally so. [[PoesLaw We hope]].

There was also a series of [[{{Literature/Doom}} novelizations by Dafydd ab Hugh and Brad Linaweaver]]. Four in all, the first two--''Knee Deep in the Dead'' and ''Hell on Earth''--were based on the first and second games, respectively. The final two, ''Infernal Sky'' and ''Endgame,'' went their own direction with the plot. These novels have a small cult following. There are also two novels based on ''Doom 3'' by Matthew Costello, who also wrote that game's script.

As for other products in the franchise, there are two cell phone-based {{RPG}}s, an [=iOS=]-based RailShooter, and a board game with expansion pack.

----
!!This game is the {{Trope Namer|s}} for:
* {{BFG}}
* DoomDoors
* TeleFrag

----
!!Notable Doom mods with their own page are:
* ''VideoGame/ActionDoom2UrbanBrawl''
* ''VideoGame/BatmanDoom''
* ''VideoGame/BrutalDoom''
* ''VideoGame/ChexQuest''
* ''VideoGame/GhoulsVsHumans''
* ''VideoGame/{{Hacx}}''
* ''VideoGame/{{Harmony}}''
* ''VideoGame/HideousDestructor''
* ''VideoGame/MegaMan8BitDeathmatch''
* ''VideoGame/{{Reelism}}''
* ''VideoGame/TurbochargedArcade''
* ''VideoGame/ZDoomWars''
* ''VideoGame/SonicRoboBlast2''

----
!!This game provides examples of:
* OneHundredPercentCompletion: The classic games has percentage counter for how many monsters were killed, items, and secrets found in each level.
* AbandonedMine: [[ExactlyWhatItSaysOnTheTin "The Abandoned Mines"]] in ''Doom II''. Granted, it doesn't look much like actual mines (then again, no level in the classic Doom games looks like anything) and it's supposed to be located in Hell, but it does have areas that look like giant underground excavated caverns which probably inspired the level design of ''Doom 3''.
* ActionizedSequel: While ''Doom I'' is fast-paced, it is generally willing to have scary moments as shown with several fights through a maze filled with Pinkies and imps while the lights flicker on and off. The second game goes for the "EXPLOSION TIME" brand of fun people associate with the series. The third slows things right down and adds in more SurvivalHorror elements to the mix.
** It is also inverted before ''Doom 3'' showed up: in between ''Doom II'' and ''Doom 3'', there was ''Final Doom'' and ''Doom 64''. ''Final Doom'' was a ''Doom II'' style death orgy that had two whole level packs. ''Doom 64'', however, is a horror game with just this spooky droning soundtrack.
* AdaptationalWimp: Councillor Swann. In the game he's [[BadassBureaucrat decisive and effective]], in the novelization he's a standard spineless ObstructiveBureaucrat.
* AllThereInTheManual: The backstories to just about all the classic series games.
** Also, the novelizations are the only time "Doomguy" is given a proper name (for those wondering, it's Flynn "Fly" Taggart for the classic series novels, and John Kane for the ''Doom 3'' novels). WordOfGod is that the games' protagonist is deliberately not given a name because it's supposed to be '''''you''''', the player.
* AlwaysAccurateAttack: The arch-vile's attack will always hit the target unless it leaves the line of sight before it finishes. Only the marine can effectively dodge it. Partial invisibility won't cause it to miss, but does affect the knockback direction.
* AlwaysChaoticEvil: The demons all have nothing but malicious intent towards everyone and everything around them, even other demons
* AmmunitionBackpack: As a power-up. Not only does it give you one of each "small ammo pack" (one pistol clip, four shotgun shells, one rocket, and one 20-volt energy cell), if it's your first, it doubles your ammo-carrying capacity (You can carry 400 bullets instead of 200, and so on).
* AncientAstronauts: In ''Doom 3'', [[spoiler:Earth had been colonized by ancient Martians -- who seems to be humanoid creatures with the same size and width as Humans -- who teleported there to escape a demonic invasion. Some scientists ask themselves if the Martians are ancestors of Mankind.]]
* AndIMustScream: Some crushing floors in the first two games only crush, they never release. If you let yourself be smashed by these and happen to have enough health, you'll remain trapped alive in concrete. Have a nice stay if it's multiplayer and no one else can find and kill you to release you. Thankfully, a rather rare bug.
* AndYourRewardIsClothes: A meta-example: the XboxLiveArcade port of ''Doom II'' offers two Avatar Awards. You'll get a Doom t-shirt for finishing the regular game, while completing the XBLA exclusive episode "No Rest For the Living" will net you a full [[http://www.gamesradar.com/f/the-26-best-avatar-awards-and-how-to-get-them/a-20110310133244754094 Doomguy costume]].
* AntiFrustrationFeatures: In ''Doom 3'', if your health is lower than 10 and you go into the next level, the game will bump your health up to 25 percent to give you a fair chance.
* ApocalypticLog: All over ''Doom 3''.
* ArmCannon: The Cyberdemon and the Mancubus, and the Bruiser in ''Doom 3''[='=]s ''Resurrection of Evil''.
** In ''Doom 3'', the BFG isn't so much wielded like a gun as it is worn like a giant glove of death. The only one who actually ''carries'' the BFG is [[spoiler:Sabaoth[=/=]Sergeant Kelly]].
* TheArtifact: The computer screens in the star textures contain the text "Tei Tenga" left over from Tom Hall's ''Doom Bible'' where the game was planned to be set. After Tom was voted off the island the game moved to Mars' moons.
* ArtifactMook: When you add up all the bodies, the extensive bloodstains, the skeletons, the zombies and the Lost Souls you fight in ''Doom 3'', there seem to outnumber the human population in an area quite a bit.
* ArtifactOfDoom:
** The Artifact from ''Resurrection of Evil'', which is a large heart with bits of metal attached.
** The Unmaker from ''Doom 64'', apparently carved from Demon's souls.
** Also the Soul Cube from the original ''Doom 3'' although that was created to defeat the demons, rather than by them.
* ArtificialBrilliance: In ''Doom 3'', the enemy's combat A.I. is very simple, but their path-finding A.I. is actually remarkably well-done; if you use an elevator or ladder to escape from a charging enemy, they can actually circle around the entire map to make their way to your new location. This is only noticeable if you go out of your way to toy with the A.I., however.
* ArtificialStupidity: It doesn't matter if a fellow monster is in the way, ''all'' monsters will start attacking upon sight of the player, and if their attack connects to a fellow monster, they'll turn on each other. Players who are out of ammo will quickly learn to start triggering in-fights. The term "monster infighting" was coined to describe this (especially when other games began featuring the same thing). There are some levels in ''Doom II'' in particular where the only way for the player to survive (barring the use of cheat codes) is to trigger in-fighting to either reduce enemy numbers or get other monsters to take out or weaken one of the big bads like the Cyberdemon.
* AscendedGlitch: Oh, wow. ''Lots.'' Most of them have been used and abused for speedruns and map-making.
** If an Archvile [[AnimateDead resurrects a monster]] who was crushed by a DescendingCeiling, that monster will become a "ghost" that can pass through (or over) obstructions and is [[KungFuProofMook invulnerable to everything except splash damage and other monsters' melee attacks]]. Once this bug was discovered, several custom maps were ''designed'' to produce this effect.
** Similarly, the shimmery "hall of mirrors" effect that occurs when a texture is missing has been adopted by some level designers to create deep water. It will still glitch if your view is below the water level, however.
** Also the "voodoo doll" bug, which can be easily created by placing two different start points for a single player. Clever mapmakers have used this bug to create traps which can teleport a player into another copy of himself, resulting in a recursive TeleFrag ([=MAP30=] of ''TNT: Evilution'' is an example). Voodoo dolls under triggered crushing ceilings can also be used to cause player deaths wherever the mapmaker wants; for example, simulating bottomless pits by triggering the ceiling if a player falls into one.
** Because the first two ''Doom'' games aren't true 3D, a rocket's splash damage isn't a sphere as might be expected; it's a cylinder of infinite height. This bit of questionable behavior, combined with actors being infinitely tall as far as collision is concerned, is what allows you to damage ''Doom II'''s final boss.
** It is possible to mess with sectors and sector references to create an "invisible staircase" effect, which was best demonstrated by a map called UAC_Dead. This in fact abuses the same glitch as deep water effect above, just the water doesn't need some of the set-up needed for bridges.
** If you trigger an action to move the floor up, but the target height is lower than current height, then the floor will move instantly (and the other way round, if floor should be moving down but the target height is higher, it will move instantly too). Combined with "invisible bridge" effect above, this allows for a fake 3D bridge which can be passed over and under, by moving the floor depending on where the player is. This is used in some custom maps.
*** It is also used heavily in ''Doom 64'' to create bridges and tunnels
* AsteroidsMonster:
** In ''Doom II'', The Pain Elemental will spawn up to three [[GoddamnedBats Lost Souls]] when it's destroyed, in a triangular formation.
*** However, if you let it live, it'll ''continually'' spawn them. Get a Pain Elemental into a LetsYouAndHimFight with another monster, and it'll spit the things like missiles. (Presumably, because if it just kept spawning them, the programming's not quite up to letting these new Lost Souls attack the monster that hit the Pain Elemental, not ''them.'')
** In the "Doom II RPG" for mobile devices, the Spider Mastermind will explode into three Arachnotrons.
* AIIsACrapshoot: {{Zig Zagged|Trope}} in ''Doom 3'''s backstory. Sentry bots are powerful fighters and efficient guides whenever you see them, but there were at least two instances where they became a threat to innocent personnel before the invasion. One seemed to come from an error during the system booting, the other because of [[DisproportionateRetribution a worker's simple refused clearance]]. In both cases, the reporter vehemently questions the bots' artificial intelligence and excessive firepower. Thankfully, they never attack the player in actual gameplay.
* ATeamFiring: Normally, monsters fire directly at the player, allowing the player to dodge. If you collect the Partial Invisibility power-up, enemies will fire wildly in your general direction (and miss more often than not.) Ironically, this can actually make it ''harder'' to avoid getting hit sometimes if you pick up a bad habit of dodging projectiles or if there are a lot of enemies in an area, because you can accidentally dodge into one of the stray ones.
* AttractMode: ''Doom'' and ''Doom II'' (and their kin) play a demo if left on the title screen for a second or two.
* AutoSave: Many source ports, such as [[http://www.zdoom.org ZDoom]] or [[http://zandronum.com/ Zandronum]], auto-save whenever the player enters a new level, whilst also having the option of manual saves.
* AwesomeButImpractical: The laser sight that replaces the crosshair in ''Doom 3: BFG Edition'' if you're playing in 3D mode. It's a lazy, cheap hack that does ''not'' actually point at where your weapon actually fires, and also sways with your gun for further confusion. This is most noticeable in the first few levels, where you'll find it extremely difficult to get pistol headshots on zombies, or cr0wn the imp with one shotgun blast. Once you start getting automatic weapons it becomes tolerable, as you can just blast your way through the rest of the game without worrying too much about precise aim thanks to the increased ammo availability of the BFG edition.
** The Berserk pack. The healing part is alright, but the Berserk pack also increases the strength of your fists, to the point that you can explode imps and zombies with them. But why would you risk rushing into a horde of enemies to punch them to death one at a time while the others tear you to shreds (fortunately, mouse controls make melee combat much less unwieldy and more feasible.)
* BackThatLightUp: The GameBoyAdvance version of ''Doom'' had more than one color scheme to compensate for the different lighting possibilities for that system.
** An early patch added several "gamma correction" settings to lighten the game, to help compensate for terrible monitors commonplace at the time.
* BadassBoast:
-->'''Swann:''' "This is the last time. I'm tired of running damage control every time he makes a mess."\\
'''Campbell:''' "Right. You're the control, and if that fails, ''I'm the damage.''"
** Unusual for a ''Doom'' boss, [[spoiler:Sabaoth]] is quite vocal, shouting demoralizations at you as you fight. [[spoiler:To be fair, back when he was your sergeant, he apparently didn't think much of you ''then'', either.]]
* BadassNormal: The marine: So {{Badass}} that in ''Doom II'', he ''[[spoiler:destroys Hell]].''
* {{BFG}}: ''The one...'' '''''THE ONLY.'''''
* BigRedDevil: The Cyberdemons and the Barons of Hell.
* BittersweetEnding: The unnamed marine in ''Doom 3'' succeeds in sealing off Hell and survives, and is found by the subsequent reinforcements, but innumerable lives were lost beforehand.
** DownerEnding: The unnamed marine in the first ''Doom'' succeeds in escaping Phobos, climbing down from Deimos and escaping Hell itself, only to find that the demon invasion has already taken hold on Earth, with billions being slaughtered. TheEnd! ([[EarnYourHappyEnding Ultimate Doom's fourth episode and the sequel has you saving what's left of humanity and ends on a triumphant note, at least.]]) There's even a miniature downer ending in the first episode, where you're transported into a darkened, inescapable room full of demons, and it's lampshaded by the game-ending text. Thankfully, you survive to go on to the next episode.
* BlackAndWhiteMorality: All the ''Doom'' games, really. Monsters from Hell trash humanity ForTheEvulz. You have lots of guns. Monsters gooify ''[[LudicrousGibs quite nicely]].'' There's not a lot of ambiguity when it comes to what you're supposed to do.
* BlackoutBasement: Some of the areas in ''Doom 3''.
* BlatantItemPlacement: In ''Doom''/''Doom II'', it's rare that item collection triggers an ambush or trap, but some do exist. However, some items are shown on display (e.g. the armor in [=E1M1=]) for no reason.
* BloodFromTheMouth: Doomguy's portrait whenever his health is low enough.
* BloodyBowelsOfHell:
** A lot of the "hell" levels of the original ''Doom'' and ''Doom II''.
** Hell starts to get its bowels all over the UAC base on Mars in ''Doom 3''. Ew.
*** Strangely, when you actually get to Hell itself there's not much in the way of fleshy bowels. Most of the environments are regular old stone.
* BodyHorror:
** Happens to [[spoiler:Sergeant Kelly]], who gets fused into a tank, and [[spoiler:Dr. Betruger]], who gets partially consumed by a demonic dragon.
** The original ''Doom'' games also have plenty of walls in the hell levels appearing to be made of human flesh, faces, or piles of corpses.
* BoringReturnJourney: The end of ''Doom II'' has your character taking the long trek back home after practically [[spoiler:destroying Hell]].
* BossArenaIdiocy: The final boss of ''Doom II'' is a giant invulnerable face in the wall of an arena which spawns endless monsters from the hole in its forehead; its only weak spot. You can shoot rockets into the hole to kill it, but such a task would be impossible if not for the arena providing a convenient elevator that reaches the height of the brain hole.
** However (even though ports supporting mouse aim do indeed ruin the level), this level is still not all that easy to win: While the elevator rises to ca. the height of said hole, firing a rocket when the player has already reached the top is rather useless since the rocket will hit a spot slightly above the hole and do no damage whatsoever. Therefore shooting the rockets has to be timed precisely. Moreover the process has to be be repeated at least three times[[note]]as the ''THING'' which needs to be destroyed in order to beat the level is only affected by the rockets' blast radius, which is a randomized value[[/note]], which can render the level a bit frustrating, especially on higher skill levels.
* BossInMookClothing: Archviles, Mancubi in ''Doom 3'', Barons of Hell, Hell Knights in ''Doom 3'', Bruisers in ''Resurrection of Evil''. Also, a huge chunk of the custom monsters in [[GameMod ZDoom's]] realm 667 beastiary.
* {{Bowdlerise}}:
** Swastikas in the [=E1M4=] were changed in later versions to allow the game to be sold in Germany. Also, German versions of ''Doom II'' do not contain levels 31 or 32.
** The Game Boy Advance ports of ''Doom I'' and ''II'' had all the in-game blood turned green. Ironically, the SNES port of ''Doom'' retained most of the original game's red-blooded violence, with only the Satanic symbols being censored.
** The BFG Edition and XBLA version of ''Doom II'' [[http://www.youtube.com/watch?v=1snCRIl16ks completely purges]] the secret ''VideoGame/Wolfenstein3D'' levels of every ''Wolfenstein'' element: NoSwastikas nor Hitler portraits, the SS guards are replaced by zombiemen squads, the unique map music themes have been replaced by the theme of [=MAP05=] for both maps and the level names have been renamed ("Wolfenstein" to "[[ClassicCheatCode IDKFA]]" and "Grosse" to "[[VideoGame/CommanderKeen Keen]]").
* BrainwashedAndCrazy: Hinted that this was [[spoiler:Sergeant Kelly]]'s fate.
* BrutalBonusLevel: The second secret level of ''The Plutonia Experiment'', "Go 2 It". Oh hell!
** You think ''that's'' bad? The Plutonia 2 equivalent, unsubtly named "Go 4 It", is the same again... on steroids.
*** Plutonia Revisited ups the ante again with "Have @ It".
** ''Doom 64''[='=]s "Hectic" is a very tiny level with a small handful of enemies, but is packed to the brim with dirty tricks and OneHitKill traps (the first room of the level is full of power-ups that will kill you if you try to get them, except for two you can only get in a very specific way.)
* {{Cancellation}}: Only two of the three planned ''Doom 3'' novels were released; the third got canned.
* CanonWelding: The cell phone {{RPG}}s are in the same continuity as ''Wolfenstein RPG'', which features the "Harbinger of Doom" as the final boss. The Harbinger gets his arm and leg blown off and swears to avenge himself on B.J.'s descendants, becoming the Cyberdemon.
* CaptainErsatz: The Spider Mastermind, a brain operating a mechanical spider body, very closely resembles Krang from Franchise/TeenageMutantNinjaTurtles. If only he'd asked Shredder to make THAT body...
* ChainsawGood: Fondly remembered and one of the iconic weapons of the series.
** Taken UpToEleven in ''Doom 64'', where the chainsaw has ''two blades''.
** ''Doom 3'' actually provides an explanation for why a base on Mars, which has no trees, would have chainsaws-they got mixed up with an order of jackhammers for mining.
* ClassicCheatCode: iddqd, idkfa, idchoppers, and so on.
* ClothingDamage: As seen in the page image, Doomguy's uniform is heavily damaged in most official artwork. Amusingly, this led to some players thinking that his armor was issued [[BareYourMidriff with an abdominal cutout]].
* CompilationRerelease: The classic series has been included few compilations across PC and other platforms.
** The ''id Anthology'' not only compiles of all the classic ''Doom'' games, it also includes ''VideoGame/Wolfenstein3D'', ''VideoGame/{{Quake}}'', and the entire ''VideoGame/CommanderKeen'' series across four CD-[=ROMs=]. This collection also added some bug fixes to ''TNT: Evilution'' and ''The Plutonia Experiment''.
** ''The Depths of Doom Trilogy'' is a PC compilation that included ''Ultimate Doom'', ''Doom II'', and ''Master Levels for Doom II'' across three [=CDs=], along with the shareware version of ''VideoGame/{{Heretic}}'', an amateur set of levels called ''Maximum Doom'', and DWANGO version 2.02 for multiplayer at the time.
** ''Doom: Collector's Edition'' for PC includes ''Ultimate Doom'', ''Doom II'', and ''Final Doom'' on a single disc. It also allows players to play the classic ''Doom'' games without using virtual machines such as DOSBox or source ports.
** The ''BFG Edition'' includes ''Doom'' and ''Doom II'', albeit the Xbox LIVE Arcade ports that have various alterations including the censored versions of the ''Wolfenstein 3D'' secret levels in ''Doom II''... on the plus side, it gives PC gamers a chance to officially play the ''Doom II'' XBLA-exclusive episode "No Rest For the Living". In November 2012, the [=PlayStation=] 3 received another compilation called ''Doom Classic Complete'', which includes the original two games plus "No Rest for the Living", as well as ''Master Levels for Doom II'' and ''Final Doom''.
* TheComputerIsACheatingBastard: A combination of FakeDifficulty and bastard map-designers, it does not matter how carefully a player clears rooms and watches dark corners as there will always be tiny, function-less, hidden, and effectively-invisible closets containing idle monsters whose sole purpose is to surprise the player from behind.
** And, to a lesser extent (at least in the base game), there's the fact that due to the way HitScan enemies (i.e., riflemen, shotgunners, etc) are programmed, they will always hit you unless you get behind cover (if they don't miss due to spread), even if they're on the other side of the map from you. While this doesn't matter much in the enclosed spaces of the base game, in some custom levels favoring open spaces, this can get very annoying.
* ContainerMaze: Some parts of [=E2M2=]: Containment Area in the first ''Doom'' is basically a maze of crates with UAC supplies.
** ''TNT Evilution'' Map 11: "Storage Facility" takes this UpToEleven.
* ContinuitySnarl: In the end of ''The Lost Mission'', [[spoiler: The Bravo Team survivor and Dr. Meyers are both successfully rescued from Mars. This contradicts the opening screen of ''Resurrection of Evil'', where it says that only one survivor (the Doom Marine) was ever found on Mars.]]
* ContractualBossImmunity: Cyberdemons and Spider Masterminds are immune to splash damage. They only take damage from the rocket itself, not the explosion.
* CorruptCorporateExecutive: The UAC and particularly its leadership are explicitly capable of operating outside of all ethical and legal restrictions. They're a [[spoiler:rare non-villainous version (for now), in that they are not stupid like [[Franchise/ResidentEvil Umbrella Corp]] in believing that unleashing hellish monstrosities is a GOOD idea.]] The main antagonist, [[spoiler:Dr. Betruger, is in fact infamously at odds with them due to his reckless behavior even prior to the game, and the company's two representatives from the top wind up saving the human race if you make the mistake of calling for the fleet. They're also explicitly attempting to help the bizarre conditions on the Mars base as well.]]
** This trope is pretty explicitly appealed to by Sarge when he's trying to convince the player to send the call for reinforcements. [[FridgeBrilliance The developers were probably counting on players being conditioned to distrust powerful corporate-affiliated characters by the extent to which this trope is played straight in other games.]]
* TheCorruptible: ''The Lost Mission'' clarifies how Dr. Bertruger ended up allying himself with the forces of Hell. [[spoiler: apparently, he was already into the occult, and when the teleportation experiments began the demons contacted him in his dreams and offered him vast power in exchange for Earth.]]
* CoversAlwaysLie: The cover of the first game shows Doomguy holding what seems to be some kind of sub machine gun or small assault rifle, despite the game having no such weapon. It did, however, exist in the alpha -- but that weapon was turned into a chaingun during development.
** It eventually made its way into ''Doom 3'', albeit with a redesigned appearance.
* CriticalExistenceFailure: Played straight for all enemies. Cyberdemons, Spider Masterminds, and Arachnotrons are more justified with the former launching rockets and the latter two being mostly robotic.
* CutAndPasteEnvironments: It has been noted that many areas in the new "Lost Mission" campaign in ''Doom 3 BFG Edition'' are simply made up of rooms from vanilla ''Doom 3'' copy and pasted together.
* DamageDiscrimination: With the exception of bullets, monsters are immune to their own kind's projectile attacks.
* DamageSpongeBoss: Cyberdemons and Spider Masterminds.
** Although they weren't bosses (except for the 'Bruiser Brothers' at the end of the first episode) Barons of Hell were considered to have hit points WELL out of proportion with their actual threat level. This led to the introduction of Hell Knights in ''Doom II'', which were about as dangerous (their plasma orbs and claw attacks did the same damage), but only half as tough.
* DamnYouMuscleMemory: ''Doom 3: BFG Edition'' maps sprinting to the left thumbstick button like most contemporary shooters. But while those shooters only require you to tap the button once, in this game you have to hold it down to sustain the sprint. This can also be confusing for those that have played the original Xbox version where the sprint button is mapped to the left trigger.
* DarkerAndEdgier: ''Doom 3''. Definitely darker (har har), but it includes a storyline and several [=PDAs=] one can find to expand on how Hellish (har har) UAC became. It also introduces a lot more SurvivalHorror elements and contains jump scares, and makes combat a bit slower.
** Just to amplify the difference, you can take a look at the [[http://doomwiki.org/wiki/Special:NewFiles photo gallery]]. Guess which ones are made in ''Doom 3''.
** Even the original games get progressively darker. Where ''Doom'' had most of the game with a soundtrack of rock and metal, ''Doom II'' opted for slower, darker, mood setting music. The [=PlayStation=] and Saturn versions of ''Doom'' and ''Doom 64'' went even further, introducing darker music, and remodeling/revoicing the demons to appear far more intimidating. Some parts of ''Doom 64'' are downright scary.
* DeadCharacterWalking: Has such a [[http://doomwiki.org/wiki/Player_corpses_walking bug]], [[http://games.moria.org.uk/doom/research/running-body described in detail here]], where a players killed in deathmatch becomes a mobile corpse which runs (okay, slides) around. Kinda creepy.
* DeadEndRoom: the exit chamber of [=MAP12=], though it doesn't prevent you going ''forward'', it only prevents you re-entering the rest of the map. See also AndIMustScream above.
* DeadlyDodging: A major tactic is to slip between enemies (or at least ensure one is between your attacker). If one enemy damages another with a ranged attack or barrel explosion, this results in monster in-fighting (generally resulting in one of the enemies dying.)
* DealWithTheDevil: Literally in ''Doom 3'', between Hell and [[spoiler:Dr. Betruger]].
* DeathActivatedSuperPower: Pain Elementals can summon up to three Lost Souls upon their death.
* DeathByCameo: In ''Doom II'', Creator/JohnRomero's head is the BigBad (more accurately, the Big Bad's hit-box, and it can only be found using the "idclip" cheat and walking INTO the boss' brain). And the body of the designer of level 24 of the fan-made ''Doom II'' level pack ''Requiem'' can be seen upside down on a cross in that level.
* DegradedBoss: Barons of Hell, Cyberdemons, Spider Masterminds...
** The Vagary from ''Doom 3''.
** The first two Hell Knights in ''Doom 3'' (a Bruiser Brothers homage) are much stronger than any subsequent specimens.
* DemonSlaying: You'd better believe you're going to be doing this a lot.
* DescendingCeiling: Some cleverly disguised.
* {{Determinator}}: No matter how inadequately prepared or out numbered Doomguy was, he never buckles when taking on the legions of Hell.
* DevilButNoGod: Besides the Soul Cube in ''Doom 3'', there's not a holy thing in sight.
** ''Doom RPG 2'' gives us the Soul Cube, Holy Bible (as a useless random pickup) and a [[WaterGunsAndBalloons Holy Water Gun]], which instantly blesses any water put in it. Yes, even TOILET water. And you can drink from it too.
* DiagonalSpeedBoost: Strafing and running forward simultaneously is faster than doing either independently.
* DidYouJustPunchOutCthulhu: The Icon of Sin. Did you just blow the Devil's brains out?
* DiegeticInterface: Probably averted in the whole series (although the HUD could be indication shown inside the player PowerArmor), but the trope explicitly appears in ''Doom 3'': when the player is wielding a machinegun, the ammo counter disappears from the HUD and is replaced by a number displayed on the weapon itself.
* DifficultySpike: The first two levels of Episode 4 are the hardest in the first game. Everything after that, though still pretty damn hard, pales in comparison.
* DigitizedSprites: Many monsters were made from clay and then converted to sprites.
* DistressCall: How both the original game and the movie start.
** And what you're spending the first half of Doom 3 trying to send, before spending the latter half [[spoiler:trying to close the hell portal before your reinforcements arrive]].
* DoNotRunWithAGun: The player is the only entity in the original games able to fire and move at the same time. Some mods change this.
* DoomyDoomsOfDoom: Uh...
* DroughtLevelOfDoom:
** ''Doom II'''s Level 9, "The Pit", is famous for not having quite enough ammo to destroy all the monsters, even on a full playthrough. Those wanting 100% completion usually had to resort to using the fists or chainsaw for good chunks of the level.
** "Hell Beneath", the first level of the new episode from ''Ultimate Doom'', is similarly low on ammo. Even with the level's hidden rocket launcher, killing everything is difficult.
* DualBoss: The two Barons of Hell at the end of the first episode of the original game. They get a repeat in ''Doom 3''.
* DummiedOut: A couple of things that were supposed to happen in the original games were effectively dummied out by coding errors:
** The "Ouch Face" was an expression for the Doomguy head in the middle of the status bar that was supposed to show if the player received more than 20 damage at a time. In practice, the code was written in such a way that it would only appear if the player took damage and ''gained'' at least 20 health during the same tic, something that was extremely unlikely to occur without the player actually trying to make it happen. The "Ouch face" is fixed in many source ports (such as, Boom, [=ZDoom=])
** The message "picked up a medikit that you REALLY need!" was supposed to appear if the player had less than 25% health when they picked the kit up. Unfortunately, the code checks the player's health ''after'' applying the health change for picking up the medkit, meaning it is physically impossible for the player to have less than 26% health; as a result, the message is never displayed at all (this is also fixed in source ports like [=ZDoom=]).
** There was also the BFG. The classic BFG is probably the most complicated and illogical weapon ever put in an FPS, largely due to it holding over all of the mechanics from a scrapped alpha version of itself. This "billion fireballs gun" fired a ragged burst of 40 projectiles and was scrapped because it "looked like Christmas" and slowed the game to a crawl. The ''Doom'' BFG might appear to just fire a big ball that does splash damage, but it actually does this:
### After a delay of just under a second, the BFG fires the green energy ball.
### On impact, the projectile deals a large amount of direct (not splash) damage to whatever it hit.
### The BFG's invisible mechanics come into play now. The weapon fires a spread of 40 hitscan "traces" (or "rays") evenly distributed across a 90-degree arc pointing in the direction the BFG ball was fired in, ''from the player's current position''[[hottip:*:which allowed for some multiplayer shenanigans until it was patched, such as shooting the BFG into an empty room, then peek down a different corridor in time with the projectile colliding, doing a OneHitKill to everyone in said corridor instantly]], with each ray dealing 15d8 damage. Coupled with the average damage of impact being 450 damage, the average damage of the BFG (with very little deviation, due to the ''601'' dice rolls) was 3150 damage. [[CurbstompBattle This is 150 more health than the final boss of Doom has.]]
** Most people are not aware that you can kill someone with the BFG with your back to them after firing it in a totally different room.
** Initially, an EasterEgg game of Asteroids was to be accessible from the computer map, but this was almost entirely cut. (Some references to deleted files remained in code.)
** Another piece of code that was dummied out was intended to allow for doors to slide sideways. This was meant to be used in Doom II's secret levels which are based on Wolfenstein3D levels. The code was commented out when id decided to scale down the amount of Wolf 3d assets in the WAD file. Therefore the doors in the secret levels still open just like those found throughout the rest of the game (unlike the original ''Wolfenstein'' 3D doors that opened sideways).
** Since ''Doom'' and ''Doom 2'' practically use the same executable, any Doom 2 content is technically "dummied out" in the original doom (with the original Doom mode forcefully disabling Doom II specific content in custom maps.) The lack of such protection caused problems in betas v1.5 and v1.6, where the super shotgun could be obtained by an all weapons cheat but either crashed the game or prevented you from selecting the regular shotgun.
* EarnYourHappyEnding: After destroying Mars, venturing home to Earth to find that it's been taken over, saving the entirety of the human race, then venturing to hell and [[spoiler: '''BLOWING HELL UP''']] Doomguy deserves this whole-heartedly.
* EmbeddedPrecursor: The Limited Collector's Edition of ''Doom 3'' and ''Resurrection of Evil'' on the original Xbox includes the original ''Doom'' and ''Doom II''. The latter also includes the Master Levels of ''Doom II''. The ''BFG Edition'' also includes the first two ''Doom'' games.
* EmptyRoomUntilTheTrap: This series gets off on this. You'll probably run into a seemingly empty room, [[SchmuckBait maybe containing some goodies]], until you fall into a trap where a horde of demons wants to destroy you.
* TheEndOrIsIt: The text-crawl endings to the non-PC editions of the original all suggest that demons may have made it to Earth. The PC version makes it abundantly clear with the cutscene following the text that, [[SubvertedTrope yep, they did]]. [[spoiler:[[AndYourLittleDogToo And the Doomguy's pet bunny Daisy was their first victim]]]].
* EnemyRisingBehind: It was possible in ''Doom'' although the enemies were generally easier to defend against, but were uncommon. In ''Doom 3'', monster closets are more numerous, and make less noise, making them much more frustrating to some players.
* EnemySummoner: Pain Elementals and the Icon of Sin in ''Doom II''; Archviles in ''Doom 3''.
* EnergyBall: Plasma Gun, BFG and some enemies (Hell Knights, mostly) fire them.
* EpicFail: What did the UAC want to do? Make teleporters. Result? Hell invades Earth.
** However, in ''Doom 3'', once the UAC higher ups learn about the direction Betruger is taking the project in, they send Campbell and Swann to investigate and -- if necessary -- pull the plug on the project.
* EquipmentBasedProgression: In the classic games, the player gets stronger as they find better and powerful weapons, and finding your first ammo backpack permanently gives you double the ammo capacity. In ''Doom 64'', your Unmaker has Artifacts that makes it a much more powerful weapon.
* EverythingFades: In the first two ''Doom'' games the bodies of enemies stick around forever. In ''Doom 3'', demons disappear in a fizzly animation. This was probably to lighten the load on the game's engine and RAM usage by cutting down on rendered objects. Some mods do undo this and the bodies of humans and zombies generally remain, unless damaged to the point they disintegrate.
* EvilLaugh: [[spoiler:Dr. Betruger]] gives several of those in a demonic manner. They range from cool to goofy to downright ''scary''.
** [[spoiler:Arch-viles]] give several of those also, when ''hunting you down''.
* EvilVersusEvil: You can set up scenarios like this quite easily, and some demon types, such as Cacodemons and Barons of Hell, actively despise each other.
* EvolvingWeapon: The Unmaker in ''Doom 64''. When you first get it, it fires only a single laser and isn't anything special. If you manage to collect all three Demon Artifacts hidden throughout the game, though, it shoots multiple lasers in a spread pattern and is even more powerful than the BFG 9000 (to the point that only about a half-dozen shots are needed to kill the FinalBoss.
* ExactlyWhatItSaysOnTheTin: [[spoiler:Betruger.]] This requires being German or knowing a bit of the language, mind, but it's funny in either case. [[spoiler: Translates into something like "deceiver", "cheater" or "swindler.]]
** ''Doom II: Hell on Earth''
* ExcusePlot: Demons have invaded Phobos/Earth/Mars! Go kill them all in an over the top and gory fashion.
-->'''WebVideo/TheSpoonyExperiment:''' They tried to apply [[{{Film/Doom}} characters and a plot]] to ''this''? It's '''''VideoGame/{{DOOM}}'''''! People play ''DOOM'' to get away from talking.
* ExpansionPack: ''Final Doom'' contained two of them in one stand-alone game.
** ''Ultimate Doom'' was a re-release of ''Doom'' featuring an additional episode.
** ''Resurrection of Evil'' is a straight, simple expansion pack for ''Doom 3''.
*** Except for the Xbox version, which was sold as a complete game due to being a console release.
* ExplodingBarrels: ''Doom II'' has a level full of them -- Barrels O' Fun -- a classic example.
** ''Doom 3'' has a variant on these with the yellow toxic barrels. Once you shoot them, they simmer for a couple seconds before exploding (though they will explode automatically if caught in the splash of another explosive).
* FaceHeelTurn: [[spoiler:Sergeant Kelly]] though whether it was before the game began or at some point during it is not made clear.
** [[spoiler:Dr. Malcolm Betruger]] could be a another example too. In a [[ApocalypticLog log]], it's said he once had been a normal human being but after he went into the portal to Hell and came back, he "changed".
* FakeDifficulty: A lot of the difficulty in ''Doom 3'' comes from the fact that it's very dark, and the flashlight is the only way to see what you're doing. You cannot use the flashlight and a weapon at the same time. The "Duct Tape" mod and ''BFG Edition'' drops the difficulty by an order of magnitude merely by letting you tape the flashlight to your smaller guns and mounted on your shoulder, respectively; it turns out it's a lot easier to play a game when you're allowed to see where and what you're shooting.
** The SNES port removed the ability to circle-strafe, making bigger enemies much harder to quickly defeat.
* FanRemake: ''Doom 64 EX'', a successor to the ''Doom 64: Absolution'' total conversion, is a fan-made recreation of the Nintendo 64 game for PC with new added features.
** The [=PlayStation=] version of ''Doom'' has a total conversion on PC (requiring [=GZDoom=]) with some enhancements and side mods to recreate the feel of the original game.
* FateWorseThanDeath: What happens to the souls that power the Artifact? It ''is'' Hell's weapon after all, so odds are that it isn't pleasant.
* FireAndBrimstoneHell: When you do see it. ''Doom 3's'' Hell is this, mixed with pulsating flesh and rivers of blood.
** In the original game Hell was mainly made of flesh, marble, wood, and stone, with the occasional river of blood and the wall of skinned faces. There are, however, exceptions, such as Mt. Erebus, which featured a charred mountain and floors of glowing, ashen rock streaked with lava.
* {{Fireballs}}: They're most notably fired by Imps.
* FirstPersonShooter: It's the GenrePopularizer. They were known as "[[FollowTheLeader Doom clones]]" for several years before the name "first person shooter" [[FromClonesToGenre became common]].
* FlyingFace: Lost Souls, Pain Elementals, and Cacodemons.
* ForebodingArchitecture: Dark areas and/or textures tend to contain Spectre demons.
** If you see random spider webs and cocooned people lying around, chances are you're about to stumble on some Trites.
* FrickinLaserBeams: The Unmaker shoots a power laser that pierces through demonic enemies.
* GameBreakingBug: The [=PlayStation=] version has a [[https://www.youtube.com/watch?v=eCaY9c-jDxQ TEXTURE CACHE OVERFLOW]] bug that crashes the game due to overloading the system's memory (especially on first-generation [=PlayStation=]s) when a very large number of enemies are present.
** Another PS1 bug that broke the game for anyone attempting to finish a level with 100% kills would sometimes occur if a monster was impacted by splash damage or was simply shot at when too close to a wall. The monster (this tended to happen most with the Lost Soul floating skull or any of the zombie soldiers) could be sent ''into'' the wall. The monster would still be visible and still in fact attempt to shoot or attack the player, but would otherwise be unkillable (and unable to harm the player). Adding to the surreal nature of the bug, the monsters would then start moving off into the distance until they effectively vanished from view (but could still be seen using the show monsters map cheat). This glitch appears to be unique to ''Doom'' proper and not the PS1-exclusive ''Final Doom'' sequel.
* GameMod:
** Lots of IWAD's and total conversions for the original ''Doom'' games are still being produced, even after almost twenty years after the release of the first game.
** Common mods for ''Doom 3'' include some of the following:
*** "Duct Tape Mod," in response to not being able to use a gun and your flashlight at the same time.
*** "Perfected Doom 3", adding new graphics, more excitement and a shoulder mounted flashlight.
*** "Last Man Standing Coop", allowing the player to play the whole game coop, with new game modes and gameplay fixes.
** For the original games, there are way too many mods to mention them all.
*** Many of the mods for the classic games can be found at [[http://www.doomworld.com/idgames/ the /idgames archive]] or at the [[http://www.doomworld.com/vb numerous]] [[http://forum.zdoom.org/ message]] [[http://zandronum.com/forum/index.php boards]] which are still fairly active. Another alternative would be to use a modern [[http://doomutils.ucoz.com/ server browser]], that comes with an auto-downloader.
*** ''VideoGame/GhoulsVsHumans'' is a mod that allows you to fight with all kinds of classes and scare the hell out of you.
*** ''VideoGame/ZDoomWars'' is a first person RealTimeStrategy that allows you to fight with all kinds of armies from different games.
*** Modder "Scuba Steve"'s ''Action Doom'' mods: The original is an homage to arcade action games like ''VideoGame/{{Contra}}'' and ''VideoGame/MetalSlug'', complete with you being a OneHitPointWonder, while ''VideoGame/ActionDoom2UrbanBrawl'' is a BeatEmUp like ''VideoGame/DoubleDragon'' done in a first-person perspective.
*** ''VideoGame/BatmanDoom'': Besides sounding awesome, it was a great technical breakthrough in the early ''Doom'' days.
*** Some mods actually make it to the mainstream media because of the RuleOfFun:
*** A mod made at the height of the 2010 World Cup, gives the Doomguy a most fearsome weapon: ''[[MundaneMadeAwesome a vuvuzela]].'' The expression on his face is what sells it.
*** It's not the first of its kind. One previous mod added in a stereo. Sounds pathetic? Well, not even ''demons'' can withstand a RickRoll, apparently.
** ''True Capitalist Doom'' (Based off of Radio/TrueCapitalist Radio) replaces the protagonist with Ghost, shotguns with "crushing cans", the BFG with a Hadoken, The [=CyberDemon=] to play the "FU Texas" song, and so forth. [[WordOfGod Ghost himself]] said he liked the mod.
** ''Aeons of Death'' adds literally ''hundreds'' of new monsters, weapons, items and even ''character classes'' from many other famous [[FirstPersonShooter first-person shooters]], including ''VideoGame/{{Quake}}'', ''VideoGame/{{Heretic}}'', ''VideoGame/{{Hexen}}'', and even ''VideoGame/HalfLife''!
*** Version 6 also adds six of the player classes from VideoGame/TeamFortress2, the [[{{Postal}} Postal Dude]], of all people, and [[VideoGame/Left4Dead even the Infected]] were brought into the fray, along with a [[SelfImposedChallenge Portal Run mode]], and Monster Mayhem, which has you dealing with enemies spawning in every-so-often in addition to those already in the maps.
** ''VideoGame/BrutalDoom'' is ExactlyWhatItSaysOnTheTin -- your weapons have all received a power upgrade (and your wimpy peashooter has been replaced with an assault rifle that can fire on full automatic and is capable of scoring headshots on enemies), the action is much BloodierAndGorier than the original game with many enemies now capable of being [[LudicrousGibs smeared all over the vicinity]], the Berserk Pack now gives you the option of doing Fatalities on enemies, and your enemies have received an upgrade as well and are fully capable of ripping you to shreds, making gameplay a lot tougher than the original.
** ''Samsara'' is an UltimateShowdownOfUltimateDestiny mod that allows you to play as Doomguy himself, [[VideoGame/ChexQuest Chex Warrior]], [[VideoGame/{{Heretic}} Corvus]], [[VideoGame/Wolfenstein3D B.J. Blazkowicz]], [[VideoGame/{{Hexen}} Parias]], [[VideoGame/{{Marathon}} Security Officer]] and [[VideoGame/QuakeI Ranger]].
** ''VideoGame/{{Reelism}}'' is a not-at-all-serious score-centric round-based survival mod in which an RNG slot machine activates at the beginning of each round to change up the game, altering special effects (such as flight, exploding enemies, or other gameplay-related stuff), weapon spawns (or lack thereof) and enemy types. Things tend to get very frantic, and that's ''before'' the boss that appears in the sixth round; as a time-waster that can be played in short bursts, it's a lot of fun.
* GameplayAndStorySegregation: The Mother Demon in ''Doom 64'' has the power to resurrect fallen demons, making them stronger than before. You fight it at the end of the game after wiping out a small army of demons, and it never tries to revive any of them.
* GatlingGood: The Chaingun. It's been a series staple and can [[MoreDakka mow down most enemies in seconds]]. The only time it becomes ineffective is against bosses (except for Vagary and [[spoiler: Sabaoth AKA the mutated Sergeant Kelly]] in ''Doom 3'').
* GiantMook: Revenant, Mancubus, Hell Nobles, Arch Vile, and in ''Doom 3: Resurrection of Evil'', Bruiser.
* GlassCannon: Lost Souls, which die quickly for high-level enemies but can quickly eat away a good 20% or so health if they land a hit.
** Cherubs do an incredible amount of damage for their size. Also Pinkies, that are pretty weak and don't do much damage per hit, but attack nonstop, and ''fast'', if close enough. Combined with the InterfaceScrew, they can bite away with impunity.
** In ''Doom II'', the Chaingunners and Revenants are this, the former only having marginally more health than former humans, but able to really put the hurt on you and even other monsters, while Revenants have relatively little health (2 Super Shotgun blasts will kill one) but shoot homing rockets at you, and [[GoodOldFisticuffs pummel you to pulp]] up close.
* GuideDangIt: Some of the secret areas can reach this level. The Containment Area in Episode 2, for example, not only has a secret room ''within'' a secret room, but there's a secret passage within that secret room leading to another part of the stage, and there's ''another'' secret room within that secret passage.
* GuiltBasedGaming: When the player attempts to exit, a humorous quit message is shown, mockingly trying to convince the player to stay and play some more.
-->"[[NotSafeForWork If I were your boss]], I'd deathmatch ya in a minute!"
* HarderThanHard: The aptly-named "Nightmare!" difficulty, the only setting where monsters you've killed will {{respawn|ingEnemies}} several seconds after they die. The monsters also [[MoreDakka shoot more rapidly]] than on all the other difficulty levels. And cheat codes are disabled. The only good thing about it is that ammo pickups contain double the normal levels of ammo... and you ''will'' need it all.
** "Nightmare!" difficulty wasn't even included in the earliest releases of the game. It's very hard in single player mode, but it's fine for co-op multiplayer games, which [[DeathIsASlapOnTheWrist let the players respawn, too.]]
* HeartContainer: Health and armor bonuses respectively can raise your health and armor past 100 though you {{cap}} at 200. Soulspheres gives you an extra 100 health and Mega Armors gives you 200 armor instantly.
* HeroicMime: The Doomguy (with the exception of the Comic) doesn't seem to have a whole lot to say. This may be because there is nobody to talk to.
** But he can express himself with the [[ChainsawGood great communicator]].
** In ''Doom II'', he talks to several people through comlinks, albeit offscreen.
* HeroicSacrifice: Presumably [[spoiler:the marine and Dr. [=McNeil=] in ''Resurrection of Evil''.]]
* HeroTrackingFailure: Enemies tend to miss their shots when the player is circle-strafing around them, unless the enemies are able to surround the player.
* HighlyConspicuousUniform: The Marines wear sensible fatigues, but their body armor comes in Day-Glo Lime Green and Peacock Blue.
* HitScan: All bullet-based weapons and the invisible part of the BFG's fire cycle in the first two games.
** In some cases (particularly Nightmare difficulty) this can make zombie marines even worse than their tougher imp counterparts. At least with imps you get a chance to ''dodge'' the projectiles that get shot at you.
* HolodeckMalfunction: The premise of the "Cleimos" WAD.
* {{Homage}}: ''Doom II'' also had two secret levels lifted almost directly from ''VideoGame/Wolfenstein3D'', the second of which ended with an appearance by a quartet of (soon-to-be) dead VideoGame/{{Commander Keen}}s.
** RetCanon: The Doomguy in the cellphone-only ''Doom RPG'' series is related to B.J.
* HyperspaceArsenal: Where the [[{{Pun}} hell]] is the Doomguy keeping all of those weapons? Not to mention the ammo; at the start of the game the player can hold 50 full-sized rockets, in addition to other ammunition and weapons. When you later find a backpack, you ''double'' your ammo carrying capacity. A hundred explosive warheads are rather impossible to fit inside a military grade backpack, and that is not accounting for your twenty kilos of bullets and five full boxes of buckshot.
* HyperspaceIsAScaryPlace: Teleporting in ''Doom 3'' will result in you seeing a [[spoiler:terrifying blood-tunnel filled with screams]]. And occasionally Hell.
* IdiosyncraticDifficultyLevels
** In the original games:
*** ''[[EasierThanEasy I'm Too Young To Die.]]'' Double ammo, half damage taken;
*** ''Hey, Not Too Rough.'' Less enemies;
*** ''Hurt Me Plenty.'' Medium difficulty;
*** ''[[Film/AClockworkOrange Ultra-Violence.]]'' More enemies;
*** '''''[[HarderThanHard NIGHTMARE!]]''''' [[ThisIsGonnaSuck Enemies are twice as fast.]] [[OhCrap So are their projectiles.]] And they respawn. At least you get double ammo.
** In ''Doom 64'' (all difficulty levels correspond to the number of enemies):
*** ''Be Gentle!''
*** ''Bring It On!''
*** ''I Own Doom!''
*** ''Watch Me Die!''
** In ''Doom 3'':
*** ''Recruit'': damage taken reduced to 60%, less enemies;
*** ''Marine'': normal damage taken, normal enemy rate;
*** ''Veteran'': damage taken increased to 170%; slightly higher enemy rate;
*** ''[[HarderThanHard Nightmare]]'': damage taken increased to ''three hundred percent'', more enemies, and your health constantly decreases to 25 points no matter what. Know that shiny Soul Cube you got at the start of the game? ''You '''will''' need it''.
* IdiosyncraticWipes: The classic [[http://doom.wikia.com/wiki/Screen_melt screen melt]] effect in every transition from the original. Some sourceports add some extra wipes.
* IncendiaryExponent: The Lost Soul. According to the ''Doom II'' manual: ''"Dumb. Tough. Flies. On fire. 'Nuff said."''
* IndecisiveMedium: The film adaptation has a suspicious amount of scenes shot in "first person".
* InfiniteFlashlight: The only upside of the torch in ''Doom 3'' is that it'll never run out of juice.
** TenSecondFlashlight: In the UpdatedRerelease, it becomes shoulder-mounted, but holds even less juice at a time than the headlamp in ''VideoGame/FirstEncounterAssaultRecon''. Fortunately, it also recharges very quickly, enough that flicking it on and off repeatedly means never staying fully in the dark.
* InsurmountableWaistHighFence: Central to much of the level design of the first two games, which did not feature any kind of jumping. Later source ports added jumping, allowing players to skip huge swaths of the classic levels by simply hopping over these obstacles.
** Taken to the extreme in Ballistyx from ''TNT: Evilution'' -- the exit linedef is on a chest-height altar that's supposed to be lowered into the ground near the end of the level, meaning you can finish a normally six minute or so map in under ''two seconds'' by simply jumping up onto it. Dead Simple in ''Doom II'' likewise has the exit switch on a waist-high platform, allowing you to finish it in three seconds just by jumping.
* {{Interquel}}: ''The Ultimate Doom'', which was published after ''Doom II'', contained a fourth episode for the original ''Doom'', which occurred before the events of ''Doom II''.
* InTheStyleOf: Bobby Prince's music for the game is based on heavy metal -- John Romero lent Prince a set of metal [=CDs=] for reference, and thus the soundtrack is [[http://doomwiki.org/wiki/Doom_music filled with]] {{Suspiciously Similar Song}}s.
* JumpPhysics: You can't jump, but you can fall fifty feet [[NotTheFallThatKillsYou without getting hurt]].
* JumpScare: The third game places ample amounts of these in each level, so much that about 20 minutes into the game, you would already became wiser to stay on your guards whenever entering a seemingly empty hallway/room.
* KaizoTrap: Halls of the Damned has a fake exit switch that instead dumps you into a room with a Cacodemon and a ton of Marines.
* KingMook: The Spider Mastermind to the Arachnotrons in the original games. Vagary to the Trites in ''Doom 3''; a Queen Mook, if you will.
* KubrickStare: In Parts 1 & 2, as Doomguy takes more damage, his head dips lower and lower, producing this effect.
* LargeHam: Betruger. So very much. He starts off overacting, and [[spoiler:gets more and more over the top and Narm-tastic as the game goes on - apparently Hell turns you into the offspring of William Shatner. He's SUPPOSED to be scary, and does have a few cool evil laughs, but it's mostly I'LL SWALLOW YOUR SOUL type stuff he yells at you from the great beyond.]]
* LaughablyEvil: The demons in ''Doom 3'' are, in an easter egg, this, believe it or not. In a hidden PDA, the demons try to instruct their fellows in how to invade:
-->"Virgin blood is best."\\
"Goat blood must be no older than 3 days."\\
"Entrails must be removed and apportioned either before death, or no later than 30 min."\\
"Candles must be sorted by tallest in back to shortest in front - never the other way around!"\\
"Most important - pentagrams must be drawn from the center to the outside and left to right."
* TheLegionsOfHell: Your opponents.
* LevelMapDisplay: You can always look at a map of what you've explored so far. If you find a computer map, you can see the entire level.
** Except in [=E1M8=]. Here the computer map is given to you right from the beginning. The level is named "Phobos Anomaly", but the map does not show [[NothingIsScarier the anomaly itself...]]
* LifeDrain: A variant with the Soul Cube. When it's flung, it kills the demon and transfers all of its remaining life energy to you. Goes well with the lack of medkits late in the game.
* LikeABadassOutOfHell: ''Literally''. In the first game, he goes from Phobos, to Deimos, to Hell, and then back. In the sequel, he ''more or less destroys hell''. And in ''Doom 64'', he finally decides to ''stay in Hell to make sure the demons don't try to invade Earth ever again''.
* LimitedSpecialCollectorsUltimateEdition: The Limited Collector's Edition of ''Doom 3'' on the Xbox [[EmbeddedPrecursor includes the two previous games]]. It also added a ''second'' secret level to the first episode in ''Ultimate Doom'' and another secret level in ''Doom II''. It also includes an slideshow of ''Doom 3''[='=]s concept art, an episode of Creator/{{G4|TV}}'s ''Icons'' on id Software, and interviews with the developers.
* LiteraryAllusionTitle: The name ''Doom'' was chosen as a ShoutOut to Tom Cruise's pool cue in ''Film/TheColorOfMoney''.
* LogicBomb: In early versions of the classic games, monsters can fight each other if they hit each other. But if they somehow hit themselves (typically via barrels, as detailed [[http://doomwiki.org/wiki/Barrel_suicide in this article]]), they will ''tear themselves apart''.
* LoweredMonsterDifficulty:
** In the backstory, the RedshirtArmy with its heavy weapons is completely useless, yet your character can kill lower-level enemies with the pistol or shotgun... But notice how you only start finding heavier weapons in later levels. [[FridgeBrilliance They're retrieved from your former buddies who managed to survive long enough to get deeper into the bases]].
** ''Doom II'' introduced Hell Knights, which are a PaletteSwap of the [[DemonicSpider Baron of Hell]] from Doom. They do just as much damage, but have significantly less health. The downside? They appear in numbers larger than Barons would have.
** Inverted in ''The Lost Mission'', where the first enemies you face have noticeably less health than normal. Given that the campaign drops you straight into the action against mid-level demons while armed with nothing but a pistol, it's explained by game design.
* LudicrousGibs: Dealing enough damage will make certain monsters burst into red splatters.
** The Soul Cube tends to do this to monsters.
* MadScientist: Dr. Malcolm Betruger, to [[spoiler:literally diabolic levels]].
* MagikarpPower: The Unmaker in ''Doom 64'' goes through this. When you first pick it up, it only fires a single laser at a slow rate. Finding the first Artifact makes it shoot faster, the second gives it a SpreadShot effect, and the third further ups the effect, effectively reaching {{beam spam}}ming levels.
* MarathonLevel: Going by the "par time" at the end of the levels, [=E2M4=] and M6 are 6 and 4 minutes respectively, while it usually never goes to 3 minutes, and ''Doom II'' has ''7'' minutes in Maps 17 and 28. Most maps on Episode 3: Inferno are really long and convoluted as well.
* MeaningfulName: The name of Dr. Betruger in ''Doom 3'' [[spoiler: means something along the lines of "scammer" in German. They probably intended it to be more like "traitor", but that would be "Verräter."]]
** The third episode of ''Doom'' (Inferno!) draws its name and its episode names from ''Literature/TheDivineComedy''. The fourth episode (Thy Flesh Consumed), and its levels except the secret level (Fear), draw their names from [[Literature/TheBible Bible]] quotations.
* MeatMoss: In ''Doom 3'', some areas are covered with, for lack of a better word, flesh masses that look like turds. If you shoot them, they sound like steel.
** And of course, the original ''Doom'' series had plenty of fleshy walls and floors once you started descending into Hell.
* MedievalStasis / SchizoTech: A very strange example in ''Doom 3''. It's 2145, humanity has an established base on Mars, has mastered plasma technology, and is foraying into the science behind atomic structure (the MFS Compactor comes to mind) and teleportation... yet:
** The most commonly found storage medium is a square-foot disk with capacity for only a few minutes of video and/or audio.
** Security forces lack any kind of enhanced vision, being forced to rely on hand-held flashlights[[note]]granted, the [[InfiniteFlashlight static transfer power supply]] is an advancement, but still[[/note]] (armor-mounted in ''BFG Edition'') with very bad quality reflectors full of artifacts and dark spots.
** All projectile-based weapons seem to use '''black powder''' given ''just how much smoke'' they produce per shot.
** All UAC workers must use a standard issue PDA that is clunkier and less versatile than most of the cheapest tablets you can find in 2012.
* MegaCorp: Union Aerospace Corporation, and in ''Doom 3'', Martian Buddy. Interestingly, despite the mention that the UAC can operate outside of legal and moral obligations, the common "corrupt" aspect of this trope is pretty much averted through ''Doom 3''. The trouble was caused by a lone MadScientist who was often at ends with the Corporation's board of directors, who are smart enough to realize that uncontrollable demons running loose are ''not'' a good source of revenue, unlike [[Franchise/ResidentEvil a certain other corporation]].
* MissionPackSequel: ''Doom II'' to its forerunner. Same engine, only a single new weapon (the double-barreled "Super Shotgun"), and a handful of new enemy types (one of which is just a slightly weaker palette swap so it can be spawned more often than its stronger brother). However, TropesAreNotBad because ''Doom'' was a great game and a slew of new maps is not unwelcome. That being said, some of the level design choices in the back half of ''Doom II'' don't exactly hold up as well as you'd hope...
** In turn, ''Final Doom'' is this to ''Doom II'' -- both were originally full 32-map mods for ''Doom II'' before they were picked up to be published by id.
* MonsterCloset: The TropeCodifier, along with TeleportingKeycardSquad. Often times rooms would be just a pedestal with an item on them, but taking the item opens up all the walls to reveal nasties. If you see a key or very good item, expect the baddies to pop out as soon as you get it.
** They did it with ''Doom 3'', where it stretched believability to the breaking point. "They're breaking through the walls!" (radio transmission)
* MookMaker: the final boss of ''Doom II'' spews out various enemies, which can telefrag you if you're not careful. And then there's the Pain Elementals, who chuck Lost Souls at you.
** The Archviles in ''Doom 3'' are this too, not limited by the number of corpses. Mostly because of EverythingFades.
* MoralGuardians: Along with ''VideoGame/GrandTheftAuto'' and ''VideoGame/{{Carmageddon}}'', this was one of the go-to scapegoats for grandstanding politicians for nearly a decade.
** The fact that Columbine shooter Eric Harris was revealed to play it certainly didn't help matters (not only that, but he made a Doom WAD of his own called UAC Labs, which made it onto [=DoomWorld=]'s Top 10 Infamous [=WADs=] list).
* MultiMookMelee: Many of the custom "slaughter maps" and NintendoHard megawads are mostly made up of these, with some fights in the infamous [[MarathonLevel Deus Vult]] map (maps 1-4 are parts of the main map, which is map05) or the ever fun "Go 2 It", which involves a brawl against several Arachnotrons and Cyberdemons. The infamous ''nuts.wad'' has [[UpToEleven so many]] enemies [[note]]10617, to be exact[[/note]] that on badly coded ports framerate slows down to a crawl, even if using a computer made 20 years after the original game. However, serious maps with that many monsters have also been made.
* MyBrainIsBig: The Spider Mastermind and the Arachnotrons.
* NamesToRunAwayFromReallyFast: [[spoiler:"Betruger" means "swindler" in German, with the added bonus of sounding like the word "betrayer." Guess what he does to you.]]
* NintendoHard:
** The first several levels of ''Doom II'' are fairly standard difficulty, but things get really insane once you hit "Dead Simple" and "Tricks and Traps".
** ''The Plutonia Experiment'', although it pales greatly in comparison to the freely-available ''Hell Revealed'' and ''Hell Revealed 2''. Oh, and the entire game on [[HarderThanHard Nightmare]] difficulty.
** Not to mention ''Alien Vendetta'', ''Deus Vult 1 and 2'', and the [=ZDoom=] version of ''[=NeoDoom=]''. The [[BossInMookClothing stupid vixens]] with their ridiculously-high 10000 hit points (and especially the [[MarathonBoss Mega Vixen with her even-more-insanely-overblown 25,000 hit points.]]) alone [[DifficultySpike sent the difficulty curve skyrocketing through the roof]] in the later levels in case all the other [[DemonicSpiders overpowered custom monsters]] didn't already do that.
*** For an idea of how much HP that actually is for those enemies, '''Cyberdemons''' only have 4,000. (and spider mastermind only having 3,000. This IS low enough for a point blank BFG-9000 blast to kill it in one shot, BTW.)
* NoFairCheating: Using "-turbo" prints a chat message from time to time. In the original, and most ports of it, cheat codes are disabled entirely in Nightmare difficulty.
* NoOSHACompliance: Toxic ooze is easily accessible throughout many levels, though some of it is explained in-game by information suggesting this was due to neglect and the happenings of Dr. Betruger.
** The strategy guide for ''Doom II'' practically calls this trope out by name: (in regard to the Radiation Suit) "OSHA may not like it, but to get the job done, you're going to have to handle some toxic waste every now and then."
** An in-game audio log in ''Doom 3'' features an "accident" report of a worker who, in a trance, stepped back into a particle beam that removed the back of his head. The new "safety" measures that the log author mentions implementing involve a locked cabinet. They do not involve barricading off the particle beam so that no one can accidentally wander into it.
* {{Novelization}}: Four books based off ''Doom'' and ''Doom II'' (with the first two being actual novelisations of the game's storyline, such as it was). And two more based off ''Doom 3''.
* NumberOfTheBeast: One of the release versions of ''Doom'' and ''Doom II'' is v1.'''666'''.
** The first map of Knee-Deep In The Dead has 666 linedefs in ''The Ultimate Doom.''
* ObviouslyEvil: Malcolm Betruger. If his generally sinister attitude, [[BilingualBonus name]], and whited out eye aren't tipoffs, then it's difficult to say what is.
* {{Oculothorax}}: Pain Elemental and Cacodemon.
* OddballInTheSeries: The two ''Doom RPG'' games for being [[ExactlyWhatItSaysOnTheTin RPGs in a shooter series.]]
** ''Doom 3'' also counts for using a completely different engine, being the only truly 3D installment in the series (not counting spinoffs.) In addition, its slowed-down gameplay and [[ExaggeratedTrope increased horror elements]] separate it from every game besides ''Doom 64'', another oddball for using these elements too (though it uses the Doom engine.)
* OneHitKill: All [=NPCs=] in ''Doom 3'' will die in one hit. ''Even a punch into an unscathed NPC's toe.''
* OnlySixFaces: ''Doom 3'' only has a handful of faces for the various human [=NPCs=], which are re-used frequently. This is most noticeable in the opening ScenicTourLevel, where you can find two guys with the exact same head standing in the same room.
* OneManArmy: This may be the current benchmark. Did we mention that he [[spoiler:BLOWS UP HELL BY HIMSELF]]?!
* OneWingedAngel: By the end of ''Doom 3'', [[spoiler:Betruger]] is transformed into a demonic dragon. In ''Resurrection of Evil'', [[ThatOneBoss he puts up a hell of a fight with his new powers]].
* TheOnlyOne: You play the lone space marine who was left on guard duty at the ship, now the only thing standing against the hordes of hell.
* OverdrawnAtTheBloodBank: ''Doom'' was one of the few video games in the early [=90s=] that demonstrates that 2D sprites can spill lots of blood shot and killed, and some enemies can be gibbed when killed by high-powered weapons.
* PasswordSave: In the [=PlayStation=] and Saturn versions of ''Doom'' and in ''Doom 64'', although ''Doom 64'' also supports a save function whereas the [=PlayStation=] and Saturn versions does not.
* PainfullySlowProjectile: Most monsters' projectile attacks move pretty slowly. Unless you're playing on [[HarderThanHard Nightmare]] difficulty.
** In ''Resurrection of Evil'' you're able to use the Grabber to snatch an enemy's fireball out of the air and hurl it back at it.
** The BFG-9000, no matter the incarnation. In ''Doom 3'', they travel so slow that you can literally ''shoot them out of the air before they hit you!'' [[spoiler:This is, in fact, how you're supposed to defeat Sabaoth.]]
** Not just limited to the monsters, Doomguy's Plasma Gun in ''Doom 3'' has this defect. Supposedly it balances out how the Plasma Gun has a zero-degree spread when sustaining fire, but it makes the Plasma Gun horribly inefficient when fighting enemies like Lost Souls, Cacodaemons, and to a lesser extent Cherubs.
* PathOfGreatestResistance: If a room is filled with bodies, you've already been there.
* {{Phlegmings}}: The Hell Knights from ''Doom 3'' have this when they roar.
* PhysicalHell: ''Doom's'' entire plot revolves around the idea that teleportation experiments on Mars resulted in portals to Hell itself, cue [[PlayerCharacter The Marine.]] Also, [[spoiler: the Martians in ''Doom 3'' already did the same thing by accident long ago, sacrificed most of their civilisation to fix it, and fled to Earth.]]
* {{Plagiarism}}: The Cacodemon is the head of the Astral Dreadnought monster taken from the cover of the ''TaletopGame/DungeonsAndDragons'' supplement ''[[http://en.wikipedia.org/wiki/Manual_of_the_Planes Manual of the Planes]]''.
* PsychoticSmirk: The marine is rather passionate about battling Hell's hordes as, after a new weapon is picked up, the protagonist ''grins devilishly'' at prospect of blowing away demonic forces with it.
** The best part is when he makes the grin while his face is covered in blood.
* PunnyName: Several songs on the soundtrack, including but not limited to Kitchen Ace (And Taking Names) and Nobody Told Me About Id.
** Bye Bye American Pie was both a play on the song name "American Pie" and one of the level designers of ''Doom II'', American [=McGee=].
* QuadDamage: The Berserk Pack multiplies fist damage by '''ten''' times. For the rest of the level. You can [[LudicrousGibs gib]] weak mooks by ''punching them''.
** There's a (hopefully) intentionally crappy mod out there called ''All Hell is Breaking Loose!'' Among such things as flying demons that shout "[[PrecisionFStrike Fuck you!]]" and flip you off when they die, the zombie soldier gib animation is replaced with them burning to death. This means that you can [[ElementalPunch set someone on fire with a punch]].
** Also the second power of the Artifact from ''ROE'' is a berserk charge that lets you one-shot any enemy in the game (except bosses) with your fists. Considering the FIRST power is BulletTime and the THIRD power is [[NighInvulnerable invincibility]] it's obvious why the Artifact is a major league GameBreaker.
* RatedMForManly: Admit it, you've always wanted to kill demons with your bare hands. The sequel takes it UpToEleven when [[spoiler: you ''blow up Hell''.]]
* ReassignedToAntarctica: The Doomguy in the original two games assaulted a superior officer who ordered him to fire on civilians. Rather than a court martial that would make them look like monsters if the reason for it got out, they decided to assign him to Mars -- a barren rock whose only notable features were scientific outposts on its moons, and which was never expected to see any sort of action.
** ReassignmentBackfire: We all know how well that turned out.
* RedEyesTakeWarning: The Spider Mastermind (AKA Spiderdemon).
* RedSkyTakeWarning: Hell.
** In ''Doom 64'', not only is Hell's sky red, but in some levels it's ''on fire.''
* ReformulatedGame: ''Doom 64''. The redone levels and enemies, darker graphics and horror-inspired soundtrack gave the game a much different ambiance than the original game, even if the gameplay is for the most part still the same.
* RegeneratingHealth: Inverted in ''Doom 3''[='=]s [[HarderThanHard Nightmare]] difficulty, where your health constantly decreases by five points every five seconds until it hits 25.
* RidiculousFutureSequelisation: A PDA message in ''Doom 3'' says "The new Quake-43 game blows my mind."
* RightHandedLeftHandedGuns: Completely averted in the original ''Doom'' games, where the Doomguy is very notably shown to be left handed; both in the way he holds his guns, and when he's using his fists.
* RoadRunnerPC: The Doom marine was intentionally faster than normal monster movement, and could be made faster with a command line option. What wasn't intentional was strafe-running (+40% speed boost), and wall hugging (massive speed boost).
* RocketJump: UrExample in first-person shooters. There's no vertical lift, but it does toss you around. One secret was specifically designed to require a rocketjump... though it can be reached just by straferunning.
* TheScapegoat: For Columbine and other school shootings.
* ScenicTourLevel: In ''Doom 3''. Unlike most examples, they give you a gun and even allow you to murder your co-workers even ''before'' things go to hell.
* SchizophrenicDifficulty: Episode 4 of ''Ultimate Doom'' suffers from this. The level progression goes like this: starts out really hard -> ungodly difficult -> not as hard -> pretty easy -> about medium -> really difficult again -> somewhat easy -> ends on a rather medium difficulty level.
* SchmuckBait: In ''Doom 3 BFG Edition''[='=]s Lost Mission, there's a room where a revenant blasts out the windows, forcing you to run through a few Imps to hit a button and close the emergency shutters. Unlike the control panels in most other similar situations, this one stays functional after you've fixed the problem. [[IdiotBall No prizes for guessing what happens if you hit it again...]]
* SequenceBreaking: [[http://doomwiki.org/wiki/Straferunning Straferunning]] and [[http://doomwiki.org/wiki/Arch-Vile_jump Arch-Vile jumps]] are just a few examples of sequence-breaking tricks.
** Memorizing some of the security codes in ''Doom 3'' and ''Resurrection of Evil'' can do anything from unlocking powerful weapons early to circumventing an entire PDA hunt.
* SequelDifficultySpike:
** The first several levels of ''Doom II'' are pretty standard difficulty. Things really ratchet up once you hit "Dead Simple" and "Tricks and Traps", with large groups of high-tier enemies appear very frequently.
** ''Final Doom'' (''The Plutonia Experiment'' and ''TNT: Evilution'') takes ''Doom II'' and ratchets it UpToEleven.
** Like many expansion packs, ''Resurrection of Evil'' is noticeably more difficulty than the original ''Doom 3'', with large groups of high-level demons regularly appearing to attack you, and the introduction of an insanely powerful GiantMook (the Bruiser) who's equipped with dual full-auto rocket launchers that can gib you in seconds. This is balanced out by the new Artifact, which grants you superpowers for a limited period of time.
* SetAMookToKillAMook: A vital survival technique, especially in levels with more monsters than you can shake a boomstick at. If an enemy damages another enemy, they will engage each other.
** The first area of [=E3M1=] didn't have enough ammunition to kill all the {{Beef Gate}}s. It was punch them to death, or get them fighting each other. Since Imps and Cacodemons both had ranged attacks, getting them to hit each other was relatively easy. Then the retaliation started...
** [=E2M9=], the secret level in the second episode, had two rooms. One with Barons of Hell, the other with Cacodemons. Again, the trick was to get them fighting each other, then maneuver for survival. (Lampshaded in the novels.)
** Map 8 of ''Doom II'' has a room with a Cyberdemon and several Barons of Hell facing away from you. The trick? Cause infighting to dispose of one group, then take down what's left. No wonder it's called Tricks And Traps.
** Map 20 of ''Doom II'' contained a large antechamber with a Cyberdemon and a Spider Mastermind on two opposite platforms. No prizes for guessing the easiest way to waste them both. The level is appropriately named 'Gotcha!'
*** This sequence exists mostly to try and answer the UltimateShowdownOfUltimateDestiny-style question of who would win. (It's usually the Cyberdemon, but the Spider Mastermind's odds improve in inverse proportion to the distance between them. ''Gotcha!'' is ''just'' on the Cyberdemon's side, although Spidey does sometimes win. In some rare cases, they can end up [[MutualKill killing each other]].)
** Lost Souls behave differently with in-fighting. They will make at most one attack when damaged (but can still exchange blows), and resume attacks on the player.
* {{Shareware}}: One of the most well known examples, ''Doom'' is probably the one title above all others which destroyed forever the "shareware is shareware because it's nowhere near good enough to sell at retail" myth. It was the first shareware product ever to be reviewed in the main pages of British ''PC Format'' magazine, instead of being relegated to the shareware section.
** ''Doom II'' did not receive a shareware release, on the other hand. This was because, according to John Carmack, many people who downloaded the shareware episode Doom and beat it mistakenly considered themselves to have "beaten Doom" when they beat the demo.
*** Also because shareware was essentially a distribution method: download the (longer than average) demo, and if you like it, mail order the full version. ''Doom II'' was conceived as a retail product from the start, so all of that was unnecessary. And then Id decided to rerelease ''Doom'' at retail, as well...
** Carmack has [[http://www.wired.com/gamelife/2013/12/john-carmack-doom/ said in a 20th-anniversary interview]] that shareware was actually not such a great fit for ''Doom''. Not because any problem with the strategy itself, but because the game was such an obvious generational leap forward in game technology at the time, ''it literally sold itself'', without need of any marketing gimmicks.
* ShootTheMedicFirst: The Archvile in ''Doom II'' can revive fallen foes, so killing this guy first is essential. However, he can also deal out a ton of damage with his line-of-sight attack. In [[GameMod ZDoom]], it is possible to create enemies that can resurrect fallen foes via Decorate. Again, death for these guys should be top priority.
* ShootTheShaggyDog: The original screws you over ''twice'':
** First, after defeating the Barons of Hell in the final level of the first episode, the only way out is through the teleporter... [[spoiler:which takes you to the lost Deimos base, where you're immediately overwhelmed by monsters and die (the coding in that room ends the level once you reach 11 HP or lower)]]. Specifically, [[spoiler:you die and go to Hell]], but since Deimos was mysteriously teleported [[spoiler:to Hell, nothing really happens]]. The debriefing text really drives it home: "Once you beat the big badasses and clean out the moon base, you're supposed to win, aren't you? Aren't you? Where's your fat reward and ticket home? What the Hell is this? It's not supposed to end this way!"
** And of course, the end of episode three. The SpaceMarine escapes from Hell and returns to Earth... only to find that the demons he had been fighting have already invaded. [[SequelHook Cue the the sequel.]]
* ShortRangeShotgun: While the original pump-action shotgun was somewhat realistic, the double-barreled shotgun from ''Doom II'' was probably the {{Trope Maker|s}}, as it hit with the force of a bazooka but was was hopelessly inaccurate at further than arm's reach. ''Doom 3'''s only shotgun followed suit. Of course, considering how 2/3rds of the game are basically corridors, you'll spend a good amount of time within 2 meters of your enemy, which is why this gun is still the most practical gun to use in the game.
* ShoutOut: As mentioned in {{Homage}} above, the VideoGame/Wolfenstein3D levels in ''Doom II''. One of them even have dead VideoGame/{{Commander Keen}}s hanging in the ceiling.
** On the source port side, [=ZDoom=] has the developer's console cheat "anubis". Typing it in and pressing enter results in every monster in the game fleeing at the sight of you. Why? Because the message displayed when you hit enter is [[Anime/RoninWarriors QUAKE WITH FEAR]]. Typing "anubis" again and hitting enter deactivates the fear effect with the message "No more Ogre Armor".
** Also, the ancient Martian panel showing off [[spoiler: the last Martian using the Soul Cube]] is actually a recreation of the cover art above. Parts of the mural are broken off (notably heads), though.
** In the film, DwayneJohnson actually had to fight to keep the "BFG" reference. There's also Pinky (who gets chainsawed), a Hellknight, and Reaper saying "Hell on Earth".
** ''Doom 3'' had [[Creator/{{Capcom}} Nabcom]] retro arcade consoles scattered about the early levels. This included one console you could actually play, ''Turbo Turkey Puncher'', a GameWithinAGame based on graphics from the original ''Doom'' games.
** ''Doom II'' has this:
-->YOU WANT TO QUIT? THEN, [[VideoGame/UltimaIV THOU HAST LOST AN EIGHTH]]!
** Episode 4 of ''Ultimate Doom'' and all the levels within, excluding the secret one, have names based on biblical verses.
** ''Doom II'' was released the same year KurtCobain killed himself with a shotgun. [=MAP21:=] Music/{{Nirvana}} has a shotgun in the very first sector.
** ''Doom 3'' will compliment the user on their memory if you open the console and type in a classic ''Doom'' cheat code.
** [=E4M1=] of ''Ultimate Doom'' has the Music/NineInchNails logo inscribed in a secret area.
* SightedGunsAreLowTech: How exactly would one aim any of the guns in the third game in RealLife?
** None of the weapons in classic ''Doom'' except the pistol and the shotguns have sights, either[[note]]the Rocket Launcher's worldview sprite has a rear sight if you look really close, but the player character fires it from the hip anyway[[/note]].
* SlaveMooks: The zombies in all of the games.
* SmolderingShoes: The Cyberdemon's death animation in the original series.
* ASpaceMarineIsYou: Possibly the UrExample, although most of the cliches are only found in the backstory from the game manual.
* {{Speedrun}}: These games developed one of the earliest online speedrunning fanbases.
* SplashDamage: The always venerable rocket launcher, along with the classic ExplodingBarrels. BFG, the biggest gun in the game, does ''not'' deal blast damage in the traditional sense, though; it instead fires a cone of invisible beams (from the ''player'', not the projectile) when the main projectile hits anything.
* SpiderTank: The Spider Mastermind(s) and the Arachnotrons.
* StandardFPSGuns: Fists, Chainsaw, Pistol, Shotgun, Chaingun, Rocket Launcher, Plasma Rifle, BFG. ''Doom'' was very important in creating/popularizing this one.
* StockSoundEffects: Pretty much everything, from the monster roars to the launch sound of the monster spawn cubes in [=MAP30=] (all three of the officially-published Maps 30), thanks to id licensing sound FX from the Sound Ideas library. This is why all, or nearly all, of the FX used in ''Doom'' sound familiar to movie buffs; they've been used in many movies and TV shows, both before Doom and since. In fact, one of the stock sounds is known today as DoomDoors.
* TheStoic: The marine from ''Doom 3''. Never shows any form of emotion on his face, even fear, just frowns when new sorts of monsters appear. The only time he shows fear is when he meets the Cyberdemon.
** [[Comicbook/{{Doom}} He probably just realised it must have huge guts]].
* StrangeSecretEntrance: Some of hidden levels in the series are like this. For example, getting to one secret level required you to blow yourself off a ledge by firing your rocket launcher into a wall at point blank range.
* StupidEvil: Dr. Malcolm Betruger, who apparently has no actual motive for attempting to transform Earth into Hell and its people into screaming demon-fodder. It is implied, however, that he has been possessed or is in some way controlled by the demons. The novels indicate he was an ordinary scientist who was subject to MoreThanMindControl, alternatively ''The Lost Mission'' campaign indicates he always had an obsession with the occult and was offered ultimate power by the demons in exchange for Earth.
* SummonBiggerFish: See SetAMookToKillAMook above. If you can get powerful monsters to fight each other or mow down cannon fodder, you can save yourself a lot of trouble.
* SupernaturalGoldeyes: Picking up invincibility (or turning on God Mode) turns the Doomguy's eyes gold.
* SuperTitle64Advance: ''Doom 64''. It was originally supposed to be called ''The Absolution'', but got its name changed to follow along with the naming convention of other 64 titles. Unfortunately, this led to people mistaking it for yet another port of the original game, when in fact it is a unique game.
** The [=PlayStation=] port of ''Doom'' has the subtitle "''Custom [=PlayStation=] Edition''".
* SurprisinglySuddenDeath: The first time you see a Lost Soul in '''Doom 3''', it rips itself away from within a female scientist's head.
* SymbolSwearing: Doomguy's reaction upon finding the Unmaker in ''Doom 64'': "What the !@#%* is this!"
* TankControls: The default setting for the [=PlayStation=] and Saturn versions of ''Doom'' and ''Doom 64''. You can change the controls in the [=PlayStation=] and Saturn versions although the customization is not as extensive as ''Doom 64''.
* TeleFrag: Just like "frag", it was also first coined in ''Doom'' multiplayer matches. Some ''Doom'' levels allow you to telefrag monsters (e.g., [=E4M2=] in ''Ultimate Doom''). ''Doom II's'' final boss can also telefrag you if its monster-spawning projectile makes its impact right where you're standing. [[note]]"Last Call" ([=MAP30=] of ''TNT: Evilution'') has a second Player 1 start in a sealed-off area -- and most of the islands in the lake between the start and the main part of the level have teleport linedefs which take you to this area, so if you don't take ''exactly'' the right route across the lake, you telefrag ''yourself''.[[/note]]
** If you're playing Doom 3's co-op mod, telefrags are possible (yes, STILL) ''at the beginning of the level'' if your teammate spawns on top of you. [[http://www.youtube.com/watch?v=9Y_PLk3SBpM#t=5m55s Seen here]], as Grah kersplats Draikk simply by materializing.
** Telefrags also ignore whether the telefragged is invulnerable or not and just outright splats them. To be exact, "invulnerable" (whether by PowerUp or by GodMode cheat) means "immune to attacks scoring 1000 {{Hit Point}}s or less of damage", but a telefrag does 10,000 HP damage.
* TeleporterAccident: A teleporter breaches hell in the backstory.
** And they just plain ''fail'' in ''Doom 3''. [[spoiler:Only they actually succeed. Betruger's teleporter "malfunction" was a deliberate reaction to Swann and Campbell nosing around.]]
** [[TheMovie "He went to one galaxy, his ass went to another."]]
** ''Doom 3'' has a PDA Audio entry detailing a lab monkey being split in half. Literally. The upper half went there and the lower half stayed behind.
* TeleportingKeycardSquad: More often than not, you can expect to find a horde of demons swarming upon you when you pick up a keycard.
* ThereIsNoKillLikeOverkill: The "Russian Overkill" mod adds dozens of ludicrously-overpowered weapons (and some that are not quite so overpowered but are either funny, clever, or just plain bizarre) that effectively remove any challenge the game ever had. At least one weapon's alternate-fire mode can one-shot a Cyberdemon. To say that some of these guns can wipe out an entire level's monster population with a single round is, in many cases, ''barely'' an exaggeration.
* TitleDrop: In ''Doom 3'', Councillor Swann states that if the demons get control of the ships, everyone on Earth is "Doomed". In ''The Lost Mission'' from the ''BFG Edition'', the load screens for Hell and Hell Outpost include a pair of quotes from the bible about the coming "Day of Doom".
** ''Doom 64'' has a sort-of example, with the final map being named after the original title for the game: The Absolution.
* TropeCodifier: For the FPS genre. For years, all FPS games were known as "''Doom'' clones".
** The rude, manly space marine has become ubiquitous since then.
** The "crate maze", as first seen in [=E2M2=]: Containment Area, has also become an FPS cliché. It originated as a good way to have a large area without overtaxing the engine.
* ToHellAndBack: [[OncePerEpisode Once per game.]] [[IncrediblyLamePun All of them one hell of a trip.]]
* UniqueEnemy: In ''Doom 3'', in the second level you encounter a "fast zombie" in the infirmary. It can run almost as fast as you can, and would have made a pretty challenging enemy if encountered in large numbers. The one you see in the infirmary is the only one in the entire game, with all other zombies being the standard "slow shambling" type.
** FridgeBrilliance kicks in when you realize said zombie...isn't actually a zombie, but rather an insane man that went to town on his body with a scalpel and had been, until the moment all hell broke loose, kept heavily sedated (As noted in the Doctor's audio log).
* UnwinnableByMistake:
** [=E2M4=]: In version 1.1, approaching the yellow key, retreating to a different room, and returning causes the crushing ceiling to be permanently lowered and sometimes blocking access to the key. That version forgot the original ceiling height whenever the crusher stopped.
** "Dead Simple" from ''Doom II'': The central stair raises once you kill all Arachnotrons. If played on Nightmare, Arachnotrons can respawn and be killed off again, allowing you to raise the central stairs out of reach.
** "Pharaoh", the first secret level from ''TNT: Evilution'', is {{Unwinnable}} in single-player mode, but not co-op mode. This is due to the yellow key being marked as "Multiplayer-Only". (But you can still complete it using straferuning, an engine bug.)
*** You can patch your TNT-IWAD with [[http://doomgate.de/content/files/ladopato/index.html Doom Patcher]]. It will create an IWAD without said bug. However, it won't fix the node-building error which is also present, so you will still be unable to get 100% kills. It's far better to use the official [=TeamTNT=] PWAD to fix both these bugs.
** "Even Simpler" from ''Doom 64'' is basically a remake of "Dead Simple," only with Pain Elementals thrown in. You have to kill every enemy, including the Lost Souls they shoot out, to advance. If they're killed next to some walls, however, the Souls they are supposed to shoot out get sucked into the walls, making it impossible to kill them.
** In ''Doom 3'' a number of doors are supposed to lock behind you once you walk through them. However, it's possible to walk through one of these doors and then back out before they close (usually because an enemy jumped out at you), and end up on the wrong side of the door when it locks, causing you to be unable to proceed furthur.
* UnwittingPawn: [[spoiler: The marine from ''Doom 3'' will become this if he sends the signal from Mars to Earth for reinforcements, playing right in to Dr. Betruger's hands. If not, Betruger will send it himself.]]
* UpdatedRerelease: After 8 years, ''Doom 3'' was re-released as ''Doom 3: BFG Edition''. It's primarily geared towards bringing the game to consoles (the only previous console release was for the original Xbox, and had noticeably decreased graphics to run on the system), but is available for purchase on the PC as well. The updated release includes improved lighting and rendering (although not as modernized as, say, the fan-made Sikkmod mod), support for 3D TV display, and (only on the PC version) support for the Oculus Rift VR headset. It also has console-oriented features such as achievements and save checkpoints. A new set of levels called "The Lost Missions" are part of the game as well. The entire game has been tweaked to be more action-oriented and closer to the feel of the original games, in contrast to the slower-paced, more survival horror-like presentation ''Doom 3'' originally had. This includes faster player speed, less ammo hunting, slightly redesigned levels, an armor-mounted flashlight, etc.
** ''Ultimate Doom'' added no new monsters or weapons (not even the new ones added in ''Doom II''), really just a new episode, to the original game. It was basically an excuse to get ''Doom'' (formerly distributed as {{shareware}}) sold in retail stores.
** The Xbox LIVE Arcade version of ''Ultimate Doom'' and ''Doom II'' has updated graphics and music, and online multiplayer. These treatments were also added for [=PlayStation=] Network's ''Doom Classic Complete'' compilation.
* VideoGameCrueltyPotential: All of the survivors you meet in ''Doom 3'' can be straight up murdered either for giggles or to charge the [[HarderThanHard nightmare mode]] item; you can even do this ''before'' the demonic invasion begins. In fact, this is actually a ''smart'' thing to do, as many of the civilians in the intro sequence become zombies. One of the cruelest is activating a machine that will strip or melt the flesh off a scientist's bones, complete with a few seconds of horror and terror as the scientist realizes what is about to happen to him. In the BFG Edition, this one gets you an achievement.
* VillainBeatingArtifact: The original version of ''Doom 3'' requires that the player use the Soul Cube to take care of the final boss Cyberdemon. This was changed both in later patches of single-player mode and in co-op mode.
** The Unmaker and Demon Artifacts in Doom 64 are a partial example. Neither are required to beat the Mother Demon, but each of the artifacts shuts down one of the enemy spawn points in the final level, as well as powering up the Unmaker until it's the most powerful weapon in the game.
* TheWallsHaveEyes: Some wall sprites have moving walls of faces staring at you, and in later episodes/levels of ''Doom'' the switches are now stone heads whose eyes glow when you hit them on. Other switches are just eyes protruding out of fleshy patches, closing when activated.
* TheWarSequence: Custom levels pitting the player against massive hordes of enemies (called "slaughter maps") are somewhat popular amongst the ''Doom'' community, the official ''Doom'' levels have a couple of their own as well, the most infamous being Go 2 It from ''Final Doom'', which is a remixed version of the first stage from ''Doom II'' with over 200 enemies, including 19 Arch-Viles and ''13 Cyberdemons'' (fortunately, you don't have to fight them all at the same time; unfortunately, you ''do'' have to fight up to 4 at a time.)
* WeirdMoon: Most of the first game occurs on Phobos and Deimos, which are the Martian moons. They are both represented as sort of small planets / big moons with an atmosphere. The actual Phobos and Deimos are just tiny bare rocks and the whole areas of Episode 1 (Phobos) and Episode 2 (Deimos) of the game are each bigger than the moons themselves.
* WellIntentionedExtremist: The Archvile is an evil healer. His death sound is a girl saying "why?" (much distorted); he wonders why on earth anyone would want to kill him, since from his point of view he's only doing good (by resurrecting dead monsters). He's also trying to burn you to death in the meantime, [[MoralMyopia which he apparently can't imagine you'd be upset about]].
* WhoForgotTheLights: ''Doom 3'' is widely thought of as suffering from this; in particular, the "duct tape mod" that allows weapon-mounted flashlights remains the most popular download for the game.
** [[MemeticMutation THERE'S NO DUCT TAPE ON MARS.]]
** Entire sections of Doom 1 and 2 would either take place in dim light, or flickering BlackoutBasement-styled areas.
*** Fortunately, keen players were able to see in all but the darkest of areas without the light-amp goggles on DOOM's default rendering (the engine rendered everything below a certain light level as pure black). However, playing the games on Zandronum's [=OpenGL=] option causes these areas to become near pitch black. There's still the savior of the automap.
** ''Doom 64'' likes to throw in dark levels as well, the Dark Citadel being the most {{egregious}} example.
* WithThisHerring: {{Hand wave}}d in the first couple of ''VideoGame/{{Doom}}'' games, where you initially do battle with the legions of Hell while carrying a single pistol. This is explained by the ExcusePlot saying that you were a sentry stationed outside the base while everyone else went in. Naturally, all those people with the [[{{BFG}} huge guns]] got killed and you're the only one left. This does not come off as being particularly convincing. This is averted in ''VideoGame/BrutalDoom'', in which the pistol is replaced by an assault rifle which remains useful for the whole game.
** Played painfully, unjustifiably straight in ''Doom 3'''s ExpansionPack, ''Resurrection of Evil''. Aside from the unmitigated, GenreBlind stupidity required to head back to Mars after the events of ''Doom 3'', the company still doesn't equip the marines tasked with exploring ancient ruins with anything deadlier than a pistol. At least they've taped a flashlight to the gun.
** Played straight in the ''Doom'' clone ''Fortress of Dr. Radiaki'', in which you start as a top-notch agent sent to investigate mysterious island... with a pistol and a ''goddamn baseball bat''. Underfinancing, indeed.
* YouHaveFailedMe: Surprisingly averted for once. While it seems that [[spoiler:Betruger]] suffers this fate by the end of ''Doom 3'', the ExpansionPack ''Resurrection of Evil'' revealed that not only did the demons give him a safe sanctuary in Hell so that he wouldn't suffer from human retaliations, despite his plans failing, but they also gave him a new, stronger and flight-capable demonic body and supernatural powers as well a commanding rank in the demonic hierarchy.
* YouKeepUsingThatWord: ''Doom'' started the FPS trend of misusing the word "chaingun" to refer to ''rotary'' guns; a chaingun is actually a single-barrel weapon which operates its bolt with an electrically-driven chain.
----