->''The Devil is real. I know... I built his cage.''

''Doom 3'' is a 2004 FirstPersonShooter in the ''Franchise/{{Doom}}'' franchise, released for both the PC and Xbox. Despite its name, it's not a sequel to the original ''VideoGame/{{Doom}}'' games, as much as a reboot. It has a darker tone then the rest of the series, with aspects of SurvivalHorror.

Just like in the original game, you're a [[NoNameGiven nameless]], [[HeroicMime silent]], badass SpaceMarine, who has just been assigned to the Union Aerospace Corporation's base on UsefulNotes/{{Mars}}. Upon arriving and reporting to your sergeant, you are given your first task: find a scientist who has gone missing in the old communications facility. At first glance, the place and assignment seem [[NothingExcitingEverHappensHere as dull as dirt]], but as you speak to other marines and workers during your search, the creepier things start to seem. Many employees seem frightened and paranoid, and then there's the fact that the whole reason you were assigned here in the first place was to replace another Marine who died during an operation. You also overhear some rather suspicious conversations held by a high-ranking UAC lawyer and his lackey, and shadiest of all, the creepy and mysterious scientist [[BigBad Dr. Malcolm Betruger]], who promises that "amazing things will happen". By the time you find the scientist, things are already creepy enough, but then Hell literally breaks loose, and you find yourself as one of the few people left alive in a base rapidly being overrun with grotesque monsters, reanimated and murderous former humans, and otherwordly, demonic imagery. It's up to you find and stop the source of the invasion, locate and aid any fellow survivors, and fight to stay alive.

An expansion pack called ''Resurrection of Evil'' was released in 2005, and takes place 2 years after the original story. In 2012, id Software released the ''[[UpdatedRerelease BFG Edition]]'', which includes a remastered and slightly retooled version of the original ''Doom 3'' game (with an armor-mounted flashlight replacing the original's controversial flashlight system, and more ammo), ''Resurrection of Evil'', an all-new mini-campaign called ''The Lost Mission'' (consisting mostly of cut content), [[EmbeddedPrecursor plus]] ''The Ultimate Doom'' and ''Doom II'', as well as the ''No Rest for the Living'' expansion that was developed for ''Doom II''[='=]s UsefulNotes/XboxLiveArcade release, making for a very packed ''Doom'' experience.

The game was adapted into two novels by Matthew J. Costello.

In 2008, id Software began work on ''Doom 4'' to follow on from this game; the result came out in 2016 and is, once again [[VideoGame/{{Doom2016}} a reboot]].

!!Doom 3 contains examples of:
* AchievementSystem: Implemented into the ''BFG Edition'', which features 50 achievements on the Xbox 360 version, 65 achievements on the PC version, and 66 trophies on the [=PlayStation=] 3 version. These achievements range from "clear ''Doom 3'' under X difficulty", "find a particular item in the game", and "killing players in a specific way in multiplayer".
* AdaptationExpansion: The novelizations either benefited or suffered from this depending on your personal taste. They include a lot more information about the UAC, character backstories, and the state of Earth, but almost the entire first book can be skipped and not miss any parts of the game.
* AdaptationalWimp: Elliot Swann in the novelizations. Game!Swann is a hardass who willingly walks into the face of death, while book!Swann plays like an expy of [[Film/JurassicPark Donald Gennaro]].
* AKA47: Mostly averted due to the futuristic weapon designs, but the assault rifle is a modified FN P90, with an ''{{Film/Aliens}}''-style digital readout for remaining ammo.
* AncientAstronauts: [[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.]]
* AntiFrustrationFeatures: 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.
* ArtifactOfDoom: The Artifact in ''Resurrection of Evil''.
* ArtificialBrilliance: The enemy's combat AI is very simple, but their path-finding AI 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 AI, however.
* 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 kill imps 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''.
* 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.''
* BigBad: Dr. Malcolm Betruger, a MadScientist and [[spoiler:EvilSorcerer]] who turns out to be in league with Hell, and wants to bring that Hell to Earth.
* BittersweetEnding: The unnamed marine succeeds in sealing off Hell and survives, and is found by the subsequent reinforcements, but innumerable lives were lost beforehand.
* BlackoutBasement: Some of the areas.
* 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 first encounter with a Lost Soul sees it burst out of the head of a female character. Many players mistook what was happening for that character's head and spinal column detaching from her body to attack you, which if anything is more horrifying.
* {{Bowdlerise}}: Due to the ''BFG Edition'' containing the HD ports of the classic ''Doom'' games, the altered red medical crosses and censored ''VideoGame/Wolfenstein3D'' levels also comes with them. Fans thankfully have created a patch that can be applied on the unique ''Doom'' IWAD files bundled with the ''BFG Edition''[='=]s PC version that restores the red medical crosses and uncensor the ''Wolfenstein 3D'' levels.
* BossArenaIdiocy: The Cyberdemon can ''only'' be harmed by the Soul Cube. The Soul Cube can ''only'' be "charged" for its attacks by killing enemies, so if you fought the Cyberdemon one-on-one, he'd be unstoppable. Luckily, he has weak minions constantly attack you, enabling you to charge up your Soul Cube again and again.
* BroadStrokes: Official descriptions for the spin-off ''Doom RPG'' imply this game is a prequel to the original ''Doom'' games, and that Doomguy in ''Doom'' and ''Doom II'', and the Marine in ''Doom 3'' are both the same character. However, ''Doom 3'' takes place in 2145, while the original ''Doom'' took place in 2022. The Marine also looks considerably different from Doomguy, and many of the visuals and storytelling elements don't mesh between games.
* ChainLetter: You can find one by checking the emails from some of the [=PDAs=] you find. The LittlestCancerPatient is dying in six months, and for each time the message is forwarded, the UAC will donate 3 credits per name to her treatment and recovery plan. According to the date stamps in the e-mails, the letter was sent out the day hell broke loose, so the UAC won't be making a large donation any time soon.
* ContinueYourMissionDammit: At various points, Kelly will tell you to continue. There may be a situation update in the announcement, or it could sometimes be general squaking (e.g. after the airlock in Communications Transfer).
* 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. On the PC version of ''BFG Edition'' at least, players can remap their controls.
* DarkerAndEdgier: 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.
* DeathByTransceiver: The introduction level has the player character listening to people die over his radio every ten seconds after the hell invasion begins. There is even a console video depicting a scientist having his neck snapped by a zombie before cutting to static.
* DestructibleProjectiles: How can you evade the homing missiles of the Revenant? Throw up a flak wall of plasma from the rapid-fire plasma rifle. If it's a straight line between you and the attacking Revenant, then the rev also gets showered in plasma bolts. [[spoiler:This is also how you deal with Sabaoth's BFG blasts.]]
* DiegeticInterface: When the player is wielding a machinegun, plasma gun, chaingun, or BFG-9000, the ammo counter disappears from the HUD and is replaced by a number displayed on the weapon itself. This is however averted in the ''BFG Edition'' as the ammo counter on the HUD is always show regardless if they have their own built-in ammo counter.
* 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.
* 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. After being surprised one time too many by what you thought was just a corpse rising up and attacking you, you may just find yourself in the habit of destroying every corpse you come across.
* ExplodingBarrels: 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).
* {{Feelies}}: Reprints of the Xbox 360 version of ''BFG Edition'' with a Xbox One compatible label includes a fold-out poster of the original ''Doom'' cover art.
* FireAndBrimstoneHell: Hell is this, mixed with pulsating flesh and rivers of blood.
* GameMod:
** Aside from stuff like the Duct Tape Mod, there are a total conversion or two. One of the most well-known, ''The Dark Mod'', uses the game's engine to modernize ''VideoGame/ThiefTheDarkProject'' (well, it used to, until the mod became a standalone fangame).
** Doom 3 Redux improves on the game's visuals, restores some cut features from original game, remasters the game's audio logs, and adds lots of modern tweaks thanks to a custom build of Sikkmod that allows for more advanced options while maintaining the original ''Doom 3'' gameplay. Sadly it's only available for the base game and not ''Resurrection of Evil''.
** Killatomate's Realistic Weapons mod tweaks how weapons handles in the original ''Doom 3'' and ''Resurrection of Evil'' and making them feel, well, [[ExactlyWhatItSaysOnTheTin realistic]]. For example, the pistol becomes semi-automatic with proper recoil and spread between shots, the shotguns have been rebalanced spread and damage output with readjusted reloading, and the chaingun now has a retuned recoil, spread, velocity, and reloading animation. The sound effects also have been replaced with sounds from real-life guns for many of the weapons of the game.
** The [=UltimateHD=] mod for the ''BFG Edition'', which not only improves some of the game's visuals and effects, it also readjusts some gameplay elements, gives enemies new AI behaviors (e.g. Imps will leap away from the player's line of sight), and retools the game's weapons and how they handle.
** Classic Doom for Doom 3 does pretty what it says on the tin, which is recreate the first episode of Ultimate Doom, ''Knee-Deep in The Dead'', in Doom 3's engine. Also WhatCouldHaveBeen, as Episodes 2 and 3 were planned, but scrapped during development. On the plus side, it has some awesome remixes of the first episode's soundtrack.
* HellOnEarth: Dr. Betruger's ultimate plan is to bring the demons to Earth.
* HelmetsAreHardlyHeroic: Unlike the Marine in the classic games, both the Marine in ''3'' and the Engineer in ''Resurrection of Evil'' go bare-headed. Which makes it a little jarring whenever you go out on the surface of Mars; you're told that your suit should have enough oxygen to get you by, which makes no sense as you're never seen putting on a helmet or even a mask. Averted by the Marine in ''The Lost Mission''; he's never shown in cutscenes, but the game's artwork depicts him wearing a helmet.
* HyperspaceIsAScaryPlace: Teleporting will result in you seeing a [[spoiler:terrifying blood-tunnel filled with screams]].
* InfiniteFlashlight: The only upside of the torch 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.
* IdiosyncraticDifficultyLevels
** ''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''.
* JumpScare: Happens often -- in particular, Imps love to crouch down behind doors and around corners, just waiting for you to come by so they can lunge at you.
* LaughablyEvil: Believe it or not, the demons are this in an Easter egg. In an easily-overlooked data terminal near the end of the game, you can download an e-mail where 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."
* LifeDrain: When the Soul Cube'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.
* MacGuffin: The Artifact in ''Resurrection of Evil''.
* MadScientist: Dr. Malcolm Betruger, to [[spoiler:literally diabolic levels]].
* MeaningfulName: The name of Dr. Betruger [[spoiler: means something along the lines of "scammer" in German. They probably intended it to be more like "traitor", but that would be "Verräter."]]
* MeatMoss: Some areas are covered with, for lack of a better word, flesh masses that look like turds. If you shoot them, they sound like you're hitting steel -- whether it's intentional or not, nobody knows.
* ModernStasis / SchizoTech: 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. The grenade smokes out so much, it seems to have a burning fuse despite the apparent electronic activation.
** You'll occasionally come across what appear to be iPods in docking stations.
** All UAC workers must use a standard issue PDA that is clunkier and less versatile than most of the cheapest tablets you could find as far back as 2012 in reality. Perhaps justified if one goes with the explanation that they're military-spec [=PDAs=] and would be bulky to prevent damage, while the UAC would have had their IT department lock down the feature set for business use.
* MinimalisticCoverArt: While the standard cover as seen above depicts a Hell Knight, the Limited Edition for the Xbox release came in a steelbook that simply depicted the game's logo against a grey background with a satanic image, some scratches, and nothing else. The cover art for the ''BFG Edition'' is even simpler, with the logo against a nearly black background resembling a wall.
* MonsterCloset: Demons have a bad habit of popping out of them. Gets ridiculous when they're literally hiding in the walls; you'll walk past a section of wall, hear a door that you couldn't see pop open, then get smacked in the back of the head with a fireball.
* MookMaker: The Archviles, not limited by the number of corpses. Mostly because of EverythingFades.
* MortonsFork: Combined with ButThouMust when at the planetary communications array. For half the game, your entire goal (according to Sergeant Kelly -- who may or may not be acting honestly) has been to send a distress call to Earth. When you arrive, you are presented with two options; obey your orders and send the distress call or obey Swann (who technically outranks everyone) and shut down the array to keep the invasion isolated to Mars. Either choice results in the same end - if you obey Sergeant Kelly, then the distress call is sent but you're later told that this just means the demons have a free ride to Earth. Cancel the message and Swann congratulates you for seeing the bigger picture... only to be interrupted by Betruger, who overrides your control and sends the message anyway (begging the question as to why you were even necessary in the first place).
* MythologyGag:
** When the player teleports to Hell late in the game, they lose all of their weapons and ammo and need to scavenge replacements. Said replacements just happen to be the ''Doom 3'' equivalents of the original lineup[[note]]fists, chainsaw, pistol, shotgun, chaingun, plasma gun, rocket launcher, BFG. Technically, the Soul Cube is also acquired in Hell, but it isn't usable until returning to Mars[[/note]].
** The ancient tablets depicting the battle between the Martians and demons is the cover art of the original Doom, except Doomguy is carrying the Soul Cube rather than a submachine gun.
* NoCelebritiesWereHarmed: Dr. Betruger bears a striking resemblance (both physically ''and'' in voice) to Sir Creator/AnthonyHopkins. In particular, to Hopkins playing [[Literature/TheSilenceOfTheLambs Hannibal Lecter]].
* NothingIsScarier: The first part of Delta Labs 1 has no combat at all, instead involving monsters passing by and appearing and disappearing just outside your view.
* OmnicidalManiac: Betruger is essentially selling out the entirety of humanity to a gruesome end for a taste of power, from what can be gathered from his motivation.
* ObviouslyEvil: Come on, just take ''one look'' at [[BaldOfEvil Doctor]] [[RedRightHand Malcolm]] [[MeaningfulName Betruger]].
* OnlySixFaces: 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.
* 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]].
* RegeneratingHealth: Inverted in [[HarderThanHard Nightmare]] difficulty, where your health constantly decreases by five points every five seconds until it hits 25.
* RidiculousFutureSequelisation: A PDA message says "The new Quake-43 game blows my mind."
* SceneryGorn: Considering that the game combines then-stunning graphics with horrific and grotesque imagery, set in dark and run-down research facilities and the bowels of Hell itself, this is a given.
* ScenicTourLevel: Unlike most examples, they give you a gun and even allow you to murder your co-workers even ''before'' things go to hell.
* SeanConneryIsAboutToShootYou: Or rather, a Hell Knight is about to devour you on the game's standard cover.
* SequenceBreaking: Memorizing some of the security codes can do anything from unlocking powerful weapons early to circumventing an entire PDA hunt.
* SetAMookToKillAMook: It doesn't happen as often as this game's predecessors, but it's possible to get enemies accidentally hit each other which will cause them to in-fight one another. There's an achievement in ''BFG Edition'' for pulling this off.
* ShoutOut:
** The logo for the "Super Turbo Turkey Puncher 3" arcade machine is a nod to the logo for ''VideoGame/StreetFighterAlpha 3'' and the game's developer, "Nabcon", is likewise to ''Street Fighter'' developer Creator/{{Capcom}}. The button layout on the arcade cabinet is also an allusion to ''Street Fighter'', albeit with two extra buttons to the right of the six colored buttons.
** Although it's a magazine-fed, semi-auto handgun rather than a revolver like [[VideoGame/{{Fallout}} other series]] to reference it, the basic pistol in the game is clearly influenced by the blaster from ''Film/BladeRunner''.
* TheSmurfettePrinciple: There is one female employee that you meet in the entire game, and she dies as quickly as she's introduced.
* TheStoic: The marine. 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.
* 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. ''Resurrection of Evil'' shows that [[spoiler:the demons turned Betruger into a powerful demon in exchange for his aid, so that was probably part of his motivation.]]
* TeleporterAccident A PDA audio entry details a lab monkey being split in half. Literally. The upper half went there and the lower half stayed behind.
* UniqueEnemy: 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.
* UpdatedRerelease: The ''BFG Edition'' features remastered versions of ''Doom 3'', the ''Resurrection of Evil'' expansion pack, and a new set of levels cut from the original game in the form ''The Lost Mission'' expansion, all with improved lighting and rendering, support for 3D TV displays, a new (though optional) checkpoint system, retooled some gameplay elements (e.g. more enemies to battle, the flashlight is shoulder-mounted, ammo is not as scarce), and achievement/trophy support. This also bundles the HD ports of ''The Ultimate Doom'' and ''Doom II: Hell on Earth'', which also gives PC players the ability to play the previously console-exclusive ''No Rest for the Living'' episode for ''Doom II''.
* VideoGameCrueltyPotential: All of the survivors you meet 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 requires that the player use the Soul Cube to take care of the [[FinalBoss Cyberdemon]]. This was changed both in later patches of single-player mode and in co-op mode.
* WrongGenreSavvy: Sergeant Kelly seems to think that the invasion needs to be treated like any other enemy force, and commands Doomguy to send a transmission for reinforcements. [[spoiler:Too bad that that is ''exactly what [[BigBad Dr. Betruger]] wants'', so as to use those ships to have the demons invade Earth. It ultimately doesn't matter because he would have sent the transmission anyway if you hadn't.]]

!!Doom 3: Resurrection of Evil contains examples of:
* AbsurdlySpaciousSewer: About two-thirds into the fifth Erebus level, players must make their way through the a series of waste tunnels containing toxic waste which requires the player to equip a special helmet to proceed through the tunnels and pick up tanks to keep the power on the helmet running. The helment mechanic however was completely removed in ''BFG Edition'', however.
* TheBerserker: What the Artifact turns the Marine into with the appropriately named "Berserk" upgrade garnered from defeating the Berserk Hunter.
* BulletTime: After defeating the first boss of the game, the Helltime Hunter, the Artifact absorbs its ability and allows the Engineer Marine to enter bullet (hell) time.
* CatchAndReturn: The Grabber other use is being able to pick up enemies' projectiles (e.g. an Imp's fireball) and fire it back at them, which is demonstrated early on by a fatally wounded marine before dying and passing on it to you. Killing enemies in this fashion may save some ammo.
* EarnYourHappyEnding: A common interpretation of the vague ending of ''Resurrection of Evil''. [[spoiler:By the climax, every single person besides the Engineer Marine and Dr. [=McNeil=] is dead. [=McNeil=] orders the marine to shut down all the core systems in Phobos Labs, [[HeroicSacrifice including the life support system]], to power up the old teleporter so he can reach the old Delta Labs and eventually Hell itself to return the artifact and stop the invasion. After battling his way through the demons, the Engineer Marine reaches Betruger/Maledict and is mortally wounded in the battle, but manages to destroy him with the artifact using his last ounce of strength. As the screen fades to white, [=McNeil=]'s voice can be heard saying "Marine, welcome home", implying that the two are in a better place for their sacrifice.]]
* TheHeroDies: [[GainaxEnding Possibly.]] See EarnYourHappyEnding above.
* TheInternetIsForPorn: An worker named James Owens on the Phobos labs was having problems with his computer running poorly and e-mailed a technician to find out what was wrong with it, which he gets a reply from the technician who found on about Owens browsing through porn sites and may attracted a virus from there.
* LightningBruiser: The Engineer Marine is this is spades once he has the fully upgraded Artifact. So fast that everything else is in bullet time, can punch hard enough to kill a Hell Knight in 1 hit, and is completely immune to any form of damage.
* NiceJobBreakingItHero: The Engineer Marine's first action upon seeing the Artifact is to just walk up and grab it. This causes the Artifact to instantly vaporize his entire team, reopen portals to Hell, and start another invasion attempt.
* NighInvulnerable: The Engineer Marine becomes this through the Artifact once it absorbs the power of the Invulnerability Hunter.
* SawedOffShotgun: The Super Shotgun you find in Sergeant Kelly's office has a noticeably short barrel for what is supposed to be a hunting shotgun.
* ShortRangeShotgun: Subverted by the Super Shotgun. Though still short ranged, it's actually a bit more accurate than the regular shotgun since there's a larger central grouping of shot.

!!Doom 3: The Lost Mission contains examples of:
* CutAndPasteEnvironments: Many areas of the mission pack are simply made up of rooms from vanilla ''Doom 3'' copy and pasted together. Justified as these were levels cut from ''Doom 3'' with some of sections being rebuilt or repurposed for the final game.
* DownerBeginning: The Lost Mission starts where Bravo Team were ambushed by demons from the main campaign, followed by a marine's lifeless body being dragged through a blood-soaked duct.
* HeroOfAnotherStory: Dr. Meyers and the Bravo Marine manage to destroy a long-range teleporter before the ''Doom 3'' marine even completes his mission.