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

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 a ''BFG edition''.

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

!Doom 3 contains examples of:

* 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.]]
* ArtificialBrilliance: 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.
* 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.
* 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.
* EarnYourHappyEnding: A common interpretation of the vague ending of ''Resurrection of Evil''. By the climax, every single person besides the 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 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.
* 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).
* FireAndBrimstoneHell: Hell is this, mixed with pulsating flesh and rivers of blood.
* 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''.
* MadScientist: Dr. Malcolm Betruger, to [[spoiler:literally diabolic levels]].
* 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 steel.
* MedievalStasis / SchizoTech: A very strange example. 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.
* MookMaker: The Archviles, not limited by the number of corpses. Mostly because of EverythingFades.
* 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]].
* 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.
* 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.
* VideoGameCrueltyPotential: All of the survivors you meet in 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 final boss Cyberdemon. This was changed both in later patches of single-player mode and in co-op mode.