Video Game / Doom³

Abandon all hope, ye who enter here.

The Devil is real. I know... I built his cage.

—Johnathan Ishii, moments before his death

Doom 3 (stylized as Doom³) is a 2004 First-Person Shooter in the Doom franchise, developed by id Software and released for both the PC and Xbox. Despite its name, it is not a sequel to the original Doom games, but rather a reboot. It has a darker tone than the rest of the series, with aspects of Survival Horror.

Just like in the original game, you're a nameless, silent, badass Space Marine, who has just been assigned to the Union Aerospace Corporation's base on 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 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 director of research Dr. Malcolm Betruger, who promises that "amazing things will happen". By the time you find the missing 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 corpses and murderous former humans, and otherworldly, 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 developed by Nerve Software and released in 2005. It takes place two years after the events of the original game, where research on Mars has resumed, led by Dr. Elizabeth McNeil, who previously alerted the UAC about the activities that led up to Hell's invasion. However, strange hauntings began occurring around facility once again. The Red Team, a Marine search team, was tasked to investigate the cause of the phenomenon insider the depths of an underground ruin, where they eventually discovered the Artifact, a weapon from Hell that was once sealed away by the Ancients. The leading Engineer, upon attempting to inspect the Artifact, accidentally reawakens it, releasing a deadly shockwave that kills his teammates while alerting its presence to the Maledict, a demonic dragon ruling over many of Hell's forces, as it sends the Hell Hunters in order to retrieve it.

In 2012, id Software released the BFG Edition for Xbox 360, PlayStation 3, and PC, which includes a remastered and retooled version of Doom 3 (with an armor-mounted flashlight replacing the original's controversial flashlight system, brighter environments, faster player movement, slower weapons, and more ammo), whereas Doom 3 required a fan-made mod for the PC version to allow a weapon-mounted flashlight. BFG Edition also comes bundled with Resurrection of Evil, an all-new mini-campaign called The Lost Mission (consisting mostly of cut content), plus The Ultimate Doom and Doom II: Hell on Earth, as well as the No Rest for the Living expansion that was developed for Doom II's Xbox Live release, making for a very packed Doom experience. It was later ported to Android for Nvidia Shield and Google Play Store in 2015. Another standalone re-release based on the BFG Edition, simply titled Doom 3, was handled by Panic Button and was released in 2019 for Xbox One, PlayStation 4, Nintendo Switch, and PC through Bethesda.net, Microsoft Store, and Epic Games Store along with the updated ports of Doom and Doom II.

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.

In January 2021, an unofficial port made the game fully playable in VR on the Oculus Quest 2. For licensing reasons, the port requires the user to sideload assets from the PC version. The VR port is based on an earlier unofficial port that moved the game into the Quest's native Android operating system. An official PSVR version was released in March 2021.

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Doom 3 contains examples of:

• 419 Scam: If you took the PDA from Larry Kaczynski, one of his messages contains a 419 scam written by a certain "John Okonkwo" (included in this link here).
• Abandoned Hospital: There's plenty of this, even outside of the actual infirmaries and medical installations. There are several instances of 'medical specimens' in vats of liquid held up in the Delta Labs, and a portion of the place has an office wing converted to hold people that gradually became zombified, as explained in PDA logs; the feel of the location owes nothing to a bad sanitarium.
• Absurdly Short Level: Delta Labs Level 4, which only has a short hallway with two zombie enemies before a fight with two Hell Knights, after which the level immediately ends with you being teleported to Hell.
• Achievement System: 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" to "find a particular item in the game" to "killing players in a specific way in multiplayer". This also carries over to the 2019 re-release of Doom 3 minus the multiplayer achievements as it only contains the game's single player content.
• Action Bomb: Some of the arachnid mooks have an explosive variant. It's crucial to kill them from a distance.
• Actionized Sequel: Zig-zagged. Instead of being the run-and-gun shooter that the previous games were, the game changed genre to a scary, moody, and slow horror shooter. In response to criticism about some of the changes, the BFG Edition made a slight turn back to the gameplay of the previous entries by giving the player more ammo, changing the lighting to make the game less dark, having slightly faster player movement, etc. However, it wouldn't be until Doom (2016) that the franchise fully returned to its fast-paced run-and-gun roots.
• Adaptation Expansion: 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.
• Adaptational Wimp: Elliot Swann in the novelizations. Game!Swann is a hardass who willingly walks into the face of death, while book!Swann behaves like an expy of Donald Gennaro. In the novel, it's also Campbell who realizes what kind of trouble could contacting the Fleet bring to Earth, not Swann.
• A.I. Breaker: Enemies that only have melee attacks (i.e. zombies or Pinkies) are completely unable to attack you if you jump up on a table or crate, and will run in circles around you rather humorously. The levels are generally designed as a flat plane (other than stairs, which enemies can manage) so you can't do this (most objects are impossible to jump on top of, unlike earlier Id Software games).
• A.K.A.-47: The machine gun is a modified FN P90, with an Aliens-style digital readout for remaining ammo.
• All Webbed Up: In areas populated with Trites, a number of webbed corpses are scattered around. Being related to them, Vagaries also have them in their choice of decoration. An interesting example is in the first Vagary's lair: one of the bodies on the ceiling twitches like crazy when you're still seeing the place through a window^note possibly because of faulty collision detection, as it only starts moving after the bay door closes after a scripted scene, but by the time you get inside, it's dead still.
• Alternate Continuity: The game returns to literal demons from literal Hell because of teleportation fuckery, but this time the UAC base is on Mars proper. Also, the project head intentionally let them through as part of his Faustian pact with Hell, rather than the demons showing up because of a teleporter accident. Rather than a ballz-to-the-wallz action shooter, it's a System Shock-like Survival Horror game.
• Ammunition Backpack: Backpacks make a comeback in this game, though they have no effect on ammo capacity; rather, they serve as a single pickup for various ammo types.
• Ancient Astronauts: 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.
• Another Side, Another Story: You spend the earlier half of the main game trying to meet up with Bravo Team, only for them to be massacred in an ambush, and the one survivor you meet is quickly killed by a Wraith. The Lost Mission reveals that there's another survivor, and you play as him in his own campaign that takes place concurrently with the latter half of the main game. And, as if that wasn't enough, an IOS game named Doom Resurrection (which came before The Lost Mission) features a different Bravo team survivor as the main protagonist, meaning that out of the whole squad two people managed to get out alive.
• Anti-Frustration Features: 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.
• Apocalyptic Log: There are a few PDAs written like this. Though your protagonist is present for the beginning of the Apocalypse, most of the story of the game, as well as the How and Why of said event, is told through the scattered Apocalyptic Logs of Mars City's scientists, soldiers and workmen. Most of them are members of the task force complaining about security problems, other members, or the occasional Things That Go "Bump" in the Night, however a few PDAs involve people trying to relay a last minute message, and the one inside of Hell details two logs about a man being toyed with for nearly two days by the demons. One man involved in the storyline gives you a data disc he asks you to send back to Earth when you escape which details the entire plan that Dr. Betruger and the powers of Hell had for Mars.
• The Artifact: The loading screens feature gameplay tips, including a few for the multiplayer mode, which are still present in the BFG Edition and subsequent rereleases despite multiplayer being removed from those versions.
• Artificial Brilliance: 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.
• Artificial Stupidity: Any monsters without a projectile attack (i.e. zombies, Pinkies, or Wraiths) had absolutely no idea what to do if the player jumped on a table out of their reach. So they'd just run in circles around the table while moaning their hearts out. Enemies with a projectile attack (i.e. Z-Sec or Imps), on the other hand, make the most basic mistake of stubbornly and relentlessly following you instead of finding a cover and waiting for you to enter the area you need to pass through in order to continue the game. This makes them very easy to dispatch — just retreat behind the nearest corner, aim your gun at it and wait until the enemy inevitably walks right into your crosshair. Always works.
• Ate His Gun: One audio log recounts a UAC private doing this with a plasma gun. According to the narrator, his entire head was vaporized.
• Awesome, but Impractical: 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.
• Badass Boast: This exchange that plays in the intro, between Councillor Swann and his bodyguard Campbell.
  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.
• Bag of Spilling: You lose all your weapons twice in the original campaign: first when Betruger turns on the portal and you get Dragged Off to Hell (it's also justified, as he may have deliberately teleported you without your gear) and later when you escape from Hell (less justified, as all your weapons other than the Soul Cube seemingly disappear for no reason when you go through the portal back to Mars). This in turn means you need to find your BFG a total of three times throughout the game.
• Big Bad: Dr. Malcolm Betruger, a Mad Scientist and Evil Sorcerer who turns out to be in league with Hell, and wants to bring that Hell to Earth.
• Bittersweet Ending: The unnamed marine succeeds in sealing off Hell and survives, and is found by the subsequent reinforcements albeit exhausted and perhaps even traumatized, but innumerable lives were lost beforehand to the point that the marine is implied to be the Sole Survivor; even if you spared him, Swann bleeds out from his grievous injuries. The Lost Mission retroactively implies there to be more survivors off-screen, but a handful at best. Also, Betruger got away and became the leader of Hell itself as the Maledict, setting up a Sequel Hook for Resurrection of Evil to conclude.
• Blackout Basement: The entire game is dark, but some areas are even more so.
  • The Coolant Control Junction area of the Alpha Labs 2 level is completely dark, thanks to EMP surges as explained by a scientist (who's carrying a lantern himself), and escorting him to the exit is an option to avoid having to juggle your own light.
  • The Hell level is really dark, and to make it worse, you lose all weapons at the start and don't get a flashlight until you return to Mars City. It's not as bad in the BFG Edition, where the armor-mounted light works as usual, and in Resurrection of Evil, where there's no inventory loss.
• Blown Across the Room: Melee attacks will send zombies flying. The shotgun Z-secs will do this to you and possibly "juggle" you to death.
• Body Horror:
  • Happens to Sergeant Kelly, who gets fused into a tank, and Dr. Betruger, who gets partially merged with a demonic dragon.
  • The Marines who are transformed into commandos are victims of this as well: their skin turns a sickly greenish-grey, their muscles expand grotesquely into tumor-like growths, and some even have tentacles burst from their arms.
  • 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.
• Bonus Feature Failure: The inclusion of the first two Doom games in the BFG Edition has retroactively became this, at least on PC when compared to their Enhanced Unity ports after they became available on PC in 2020. While the BFG Edition's version of Doom and Doom II runs at a higher resolution and provides a legitimate way to play the No Rest for the Living on PC, it also has a persistent smoothing filter applied on the screen, slower audio at a lower bitrate with the randomly pitch shifted sounds always enabled, is locked to 35 FPS, is bowdlerised^*(the medkits had the red crosses replaced with a pill and the Wolfenstein 3D levels are heavily censored), and the Nightmare! difficulty broke the fast enemies, whereas the Unity ports (after a series of patches) offers a crispier old-school appearance with the ability to play in 16:9 widescreen, has improved sound quality with the ability to turn off randomly pitch shifted sounds, can run up to 60+ FPS, has fewer censorship changes^*(the medkits uses green crosses instead of pill symbols and the alterations in the Wolfenstein 3D levels are downplayed, making the levels look more akin to the Super Nintendo version of that game), restores the fast enemy speed of the Nightmare! difficulty, and offers the ability to play No Rest for the Living along with Final Doom and Sigil among many other curated mods all in one place. Thankfully for 8th generation consoles and PC through Epic Games Store, Microsoft Store, the 2019 version of Doom 3 is available as a standalone purchase along with the Enhanced ports of Doom and Doom II.
• Boom, Headshot!: Headshots deal 2X more damage than body shots. Some of the zombies, though, make the issue moot by being headless already.
• Boring, but Practical: As the game went for a more horror themed approach, many of the fights you get into are short range ambushes; once again, the humble shotgun is the weapon of choice for wandering through corridors.
• Broad Strokes: 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, one-hundred-twenty-three years apart. The Marine also looks considerably different from Doomguy, and many of the visuals and storytelling elements don't mesh between games.
• By the Lights of Their Eyes: Zombies and melee-oriented demons⁺ranged ones dish out very bright fireballs that give away their exact location who tend to appear in especially dark areas have glowing eyes, both for Rule of Scary and as a gameplay trait that, as in the Left 4 Dead example above, marks the thing that you want to unload on without forcing you to illuminate it with your torch.
• Canon Discontinuity: Notably, Doom Eternal excluded most of this game in its massive Canon Welding of the Doom franchise (which included the first two games, Doom 64, and the 2016 game). Yes, the Soulcube is in the reboots as an Easter Egg, but it's never directly explained or powered. It is implied, however, that the events of this game did take place in the main timeline, just with some slight alterations.
• Cassette Craze: There are recordings that sometimes contain door access codes and computer passwords.
• Chain Letter: You can find one by checking the emails from some of the PDAs you find. The Littlest Cancer Patient 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.
• Chainsaw Good: The Beavertooth chainsaw deals a very high amount of damage and can wipe out even some mid-tier demons as long as you're fleet-footed to avoid their melee strikes. Similarly, chainsaw zombies are some of the most formidable former humans and can drop your health to nil in a second or two of contact. As to why there are chainsaws on Mars, a log you can read in-game mentions a delivery error — somewhere on Earth is a group of lumberjacks wondering why they got a shipment of jackhammers instead of the chainsaws they ordered.
• Cherry Tapping: You can bludgeon people to death with the flashlight.
• Co-Op Multiplayer: The Xbox port of the game and Resurrection of Evil features two player co-op for their respective campaigns via system link, LAN connection, or Xbox LIVE, while the classic Doom games can also be played through split-screen with up to four players. The campaign in the original Doom 3 on PC is single-player only, but there are mods such as LibreCoop that provides this feature for the base game and its expansion pack as well as the ability to add compatibility for custom maps.
• Combat Tentacles: The Commandos have tentacles they can use to attack you from a range. When they're not packing a chain gun.
• Competitive Multiplayer: Doom 3 features the competitive multiplayer where up to four players (although mods can raise this limit up to sixteen) in Deathmatch, Team Deathmatch, Last Man Standing, and Tournament modes through online or LAN connection. The classic Doom games included in the original Xbox version also features local deathmatch as well. These modes also carry into the BFG Edition, although this feature was disabled in the GOG.com version due to it being DRM-free release^note although it can be re-enabled through a command-line parameter and using the developer console and the 2019 version of Doom 3 completely removed all multiplayer components.
• Context-Sensitive Button: The button that normally fires your weapon becomes an "activate" command when you are near an active panel and your aiming reticule is inside it. The BFG Edition on consoles or playing the PC version with a controller shows the top face button when looking at an interactable panel, but using the Right Trigger also works the same way.
• Continue Your Mission, Dammit!: At various points, Kelly will tell you to continue and pick up the pace (even while you're in the middle of combat). There may be a situation update in the announcement, or it could sometimes be general squaking (e.g. after the airlock in Communications Transfer).
• Cosmic Horror Story: Being the Darker and Edgier deconstruction of Doom, Doom 3 shows that the franchise is this when it gets played straight. It even borrows some themes out of H.P. Lovecraft's stories. Themes such as mankind, in their age of great scientific advancements and expansion into the cosmic space, discovering things that they would be better off not finding; in this case the truth, and the portal of Hell itself - a knowledge that the mere exposure to quickly causes madness and insanity to skyrocket in UAC's research base on Mars, and mankind's insignificance before otherworldly, eldritch forces that could easily wipe us out if it so desires. The demons are more eldritch than in the original series, and even if the Doomguy is as badass as he was originally, his war against the demons is less of an One-Man Army's awesome Curb-Stomp Battle against the legions of Hell and more of a lonely survivor desperately trying to survive the incomprehensible monsters that he actually has little chance to win against. And even then, his victory is a bittersweet one, being the only survivor and whose victory merely delayed the inevitable, as the demons return in Resurrection of Evil; once again because mankind couldn't let their scientific curiosity go and found an Artifact of Doom that summoned them back again to remind us of our own insignificance against them...
• Covers Always Lie: The artwork for The Lost Mission, which was later reused for the 2019 re-release of Doom 3 and Steam Library UI artwork for Doom 3: BFG Edition as well as GOG.com's storepage and its Galaxy client. It shows an armored space marine who looks nothing like the one featured in the game proper, dual-wielding guns (which you can't do in the game), while a towering, stocky demon that never existed in the game itself is behind him. The demon is probably supposed to be the Guardian of Hell, which is the Final Boss of The Lost Mission, but it looks more like a blend of that and a Mancubus.
• Crazy-Prepared: Downplayed by the UAC. The Mars Base has lots of heavy security, such as sentry bots and minigun turrets. If that wasn't enough, many employees have stored heavy firepower, up to and including chainguns and rocket launchers, in storage cabinets. Even though they couldn't have been expecting a demonic invasion, the extra security makes you think otherwise.
• Creator Cameo: One of the guards is voiced by John Carmack. "Welcome to the Dungeon, Marine" indeed.
• Cycle of Hurting: Some enemies such as Pinky Demons and Shotgun Z-Secs can stun-lock you, especially if you're trying to reload.
• Damn You, Muscle Memory!: 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 who have played the original Xbox port where the sprint button is mapped to the left trigger. On the PC version of BFG Edition at least, players can remap their controls. The 2019 version of Doom 3 fixes the sprinting controls where tapping the button once will sustain the sprint instead of holding it.
• Darker and Edgier: Definitely darker (even to a literal extent), as 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 Survival Horror elements and contains jump scares, and makes combat a bit slower.
• Darkness Equals Death: You have to choose between the flashlight or a weapon^note unless you are escorting a scientist carrying a lantern; even then, that only happens once, the Escort Mission lasts for less than two minutes, and the overeager dumb sod rushes ahead to the exit and gets killed in an ambush. Player frustration with this arbitrary choice and the ensuing Fake Difficulty led to the famous "Duct Tape" Game Mod, in which Doomguy Takes a Third Option by attaching a flashlight to a few of his weapons. The BFG Edition takes the tack of attaching the light to Doomguy's armor, allowing the player to use weapons freely.
• Dark World: There are moments throughout the game where the hero seems to see reality change from the already wrecked, lifeless base into a blood-streaked, skeleton-littered nightmare world, only for everything to snap back to normal a second later.
• Data Pad: The standard-issue PDAs of UAC personnel. Their design is more or less like a modern-day tablet, but thicker and with a slight curve at the bottom separating the screen from what looks like an analog pad; there's also a port at the top to insert video disks. They serve the role of mobile work stations, e-mail and video playback platforms, audio recorders and electronic keys with specific clearances. They can also download the data from other PDAs, including clearance status, and indeed in most Lock and Key Puzzle sections, your task is to find the PDA of one of the people with clearance to the area you need to go to (which is always helpfully listed in the interactive panel beside the Locked Door when you try to unlock it).
• Deadly Gas: There's a level centered around escaping a location which is slowly filling with poison gas. Said gas obeys all traffic laws in that it is properly green and slowly drains your health (complete with choking sounds) up until the second when you finally hit the "Vent Gas" switch, at which point it is instantly drained from the entire location and ceases being harmful. The Mars base must have some powerful gas vents.
• Dead Weight: Fat zombies can predictably take more lead before going down. Surprisingly enough, a great number of them carry wrenches to use as clubs. Also, they are the only type that is found being chewed on by other mooks.
• Death by Transceiver: Mars City Underground, the first level with combat, has the player character listening to people fight, panic and die over his radio every ten seconds after the hell invasion begins. There is even a console video depicting a marine having his neck snapped by a zombie before cutting to static, and a marine being possessed on another screen.
• Deconstruction: The game goes to lengths to show just how terrifying it would be being a lone marine, trapped on Mars, with monsters teleporting in from Hell (literally).
• Decontamination Chamber: There are chambers with this purpose near some (but not all) experimental teleporters. They also have a bio-scan system before you enter Mars City proper.
• Degraded Boss:
  • In a homage to the original Doom, you fight a pair of Hell Knights as bosses right before you teleport into Hell. Starting with Hell you encounter them as regular enemies (but now they actually have less hit points than when they were bosses).
  • Vagary, the first boss of the game, later reappears as a mook, albeit a tough one.
• Demonic Possession: Dr. Malcolm Betruger, who is strongly implied to have been possessed or is in some way controlled by the demons after he voyaged into hell. The novels also indicate he was an ordinary scientist who was subject to More than Mind Control. Resurrection of Evil shows that the demons turned Betruger into a powerful demon in exchange for his aid.
• Demon Lords and Archdevils: The game keeps the hierarchy seen in its predecessors, but makes some changes; Barons have been replaced by Guardians, and the Cyberdemon is a unique creature rather than a class, and is explicitly stated to be Hell's greatest warrior. After it dies, Maledict takes over.
• Destructible Projectiles: How can you evade the homing missiles of the Revenant without diving for cover? Throw up a flak wall with the Plasma Gun. If it's a straight line between you and the attacking Revenant, then the missiles will get showered in plasma bolts and blow up right in its face. This is how you deal with Sabaoth's BFG blasts as well. In fact, all projectiles can be shot out of the air, with the Cacodemon's energy ball being particularly easy to hit due to its large size. That said, it's generally easier to just dodge the fireballs launched by Imps, Hell Knights, and Mancubi.
• Developer's Foresight:
  • In the first level, if you go into the bathroom and look at the mirror, you can see that the player's model is exactly how he appears in cutscenes, wearing only fatigues. In every other level, the model shows him wearing the security vest.
  • It is possible to obtain normally unobtainable PDAs from certain NPCs by killing them, like some of the workers in "Mars City Underground". These PDAs contain information like any normal obtainable PDA. The BFG Edition also count these PDAs towards an achievement.
  • NPCs in unreachable areas are called "Joe", a default name given to NPCs in the id Tech 4 SDK, though there are some exceptions:
    • In "Mars City Underground", if you noclip into the security booth and look at the security guard, it will read "T. Brooks".
    • In "Delta Labs Sector 3", if you noclip to where Bertruger is and aim at him, it will read "Dr. Bertruger".
• Devil, but No God: The game has the main character face demonic forced without any help from divine forces (which aren't said to exist anyway), unless you count the Soul Cube used by the Martians as a holy weapon. It is stated multiple times in no uncertain terms that the demons are demons, while the previous games left some reasonable doubt that they might just be weird-looking aliens from our dimension (which is what the novels went with). The ending of Resurrection of Evil at least implies that Heaven exists, but the whole thing is still vague.
• Diegetic Interface:
  • 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. BFG Edition changed this so the HUD ammo counter always shows regardless.
  • The Quest 2 port has an option to disable the HUD entirely. Health, armor, and ammo are displayed via a wristwatch on the Mariner's left wrist.
• Dragged Off to Hell: At one point, Dr. Betruger opens a portal that forcefully teleports you to Hell. You survive and proceed to chew up that place, though.
• Drone of Dread: In keeping with the more unsettling atmosphere, the game has a soundtrack and ambient sound design composed largely of subtle drones.
• Dynamic Loading: There are many speed bumps, such as waiting for a ladder to drop or door to unlock while fighting tough enemies, and winding corridors and limited paths.
• Easter Egg: Just before the Final Boss, one wall can be found featuring the id Software logo on it. Interacting with it will open a secret room where the final PDA can be found; a series of thanks and congratulations from the developers themselves, including some of the original Doom creators like John Carmack and Donna Jackson. Another one can be found under similar circumstances in The Lost Mission, this time a Rage logo which gives you access to extra health, armor and ammo.
• Elite Mooks: Revenants. They appear in several levels and are significantly more dangerous than Imps thanks to their heat-seeking missiles.
• Elite Zombie:
  • Fat zombies can absorb slightly more damage than basic zombies.
  • Flaming zombies, also known as "Bernie", shamble faster than basic zombies, but not as fast as fast zombies.
  • Fast zombies shamble almost at a jog. Only one is ever found in the base game.
  • Chainsaw zombies, which are Exactly What It Says on the Tin. They're quick and pretty tough for zombies, and if you let them in close their chainsaws can put a real dent in your health pool.
  • Commandos, the least zombie-like of all former humans, are essentially demons, able to run and jump and provoke the player; they're also tough enough to eat a direct hit from a rocket and survive. Two versions exist, one with a Combat Tentacle for his right arm and a nastier one with two normal arms and a chaingun.
• Embedded Precursor: The Doom 3's Limited Collector's Edition 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; averted in the 2019 re-release of Doom 3 as each game are available as standalone purchases.
• Emergency Weapon:
  • Fists, with a similar berserker powerup as the original. In addition to killing enemies instantly, it also slows down time and made you invincible. Of course, it was only available twice in the entire game, and it was accompanied by some rather disturbing screaming.
  • The flashlight, which deals twice as much damage as the fists and actually lets you see what you're doing, but swings twice as slowly (and, in the PC version, has shorter range).
  • The expansion Resurrection of Evil adds the Grabber, which can be used to grab barrels, crates, and even most enemy projectiles and fire them back at the sender, and in addition its Soul Cube analogue gives the same bonuses as the above-mentioned power-up from the base game, depending on how many of the Hunters you've killed.
• Empty Room Until the Trap: A frequent case, to the point it doesn't shock or surprise the player after a while. They just knew as soon as they entered the empty room and touched the item they'd immediately have to turn around and blast all the monsters that teleported into the room.
• Enemy Summoner: Archviles are reworked to do this, given that monster corpses fade away after a short time.
• Escort Mission:
  • In Alpha Labs, you have the option to escort a scientist through the Coolant Control Junction, a section of the base even darker than usual. The main pull is that he carries a lantern that provides some much-needed light. Fortunately, he's smart enough to hang back when an enemy attacks; unfortunately, he's so flimsy that the negligible Splash Damage of an Imp's fireball will kill him. If you do get him to the end of the section in question, he'll be killed in an ambush anyway, rendering your efforts All For Naught.
  • Sentry Bots are powerful little buggers who escort you through a few sections of the game. The one time they might actually die, you need to get them to the end of the area anyway and can make more. Updated versions of the game (or those who modded the original PC version) have removed the need to choose between your flashlight and your gun making this completely optional.
• Everybody's Dead, Dave: At the conclusion of the game, the nameless protagonist is the only survivor. Every single NPC he has met over the course of the game has met their end through one way or another. And it occurs once more with the protagonist of Resurrection of Evil, though McNeil may have survived.
• Everything Fades: Dead demons and gibbed bodies disappear in a fizzly animation, to lighten the load on the game's engine and RAM usage by cutting down on rendered objects. 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. There are mods that undo this behavior and allows corpses to remain.
• Evil, Inc.: The opening crawl implies the UAC could be this; but no, turns out they really are just a big science and exploration-focused conglomerate who is in way over their heads. It's ultimately played with in that, while the organization itself is fairly innocuous, some of it's staff (Bertruger) are most certainly not.
• Evil Is Not Well-Lit: The Hell level is dark enough to count as a Blackout Basement, and in the original edition, you have no flashlight while you're there.
• Evolutionary Retcon: Practically every memorable demon in the series was completely redesigned for Doom 3. Most of these redesigns made the demons appear much scarier and more formidable opponents for the player. The original imp, for example, was a large, brown creature with spikes on its shoulders that would slowly advance towards the player while hurling fireballs at them. The new imp is a slimmer grey creature with no spikes and ten eyes on its head that is capable of climbing walls and has incredible jumping ability that allows it to clear the distance across an entire room in a single leap and generally attacks with a much more aggressive style. Some of the demons that still look similar to their classic counterparts are the Revenant, the Arch-Vile, and to a lesser extent, the Mancubus.
• Exploding Barrels: Two kinds: the yellow "flammable" barrels simmer for a couple of seconds before exploding (though they will explode automatically if caught in the splash of another explosive), while the orange "highly volatile" barrels are less lenient and will explode immediately upon taking enough damage. If you have the Grabber, you can pick up either kind and toss them as an impact explosive.
• Failsafe Failure: One of the audio logs tells the story of a technician that had his arm pulled in and shredded up to the elbow by a plastic extrusion system. The machine was properly shut down and the employee had the safety key out of the machine and in his pocket, but it turned on despite the key's failsafe and without an apparent power source. According to the log's narrator, that incident is "just one in a pile". Justified by how the teleportation experiments were connecting the base to Hell – it's not hard to imagine a malevolent spirit or demon wreaking havoc with the machinery and using it to hurt and kill people.
• Fire and Brimstone Hell: Hell is this, mixing magma and fire with pulsating flesh and rivers of blood.
• First Day from Hell: Literally so. The Marine has just started his first day on duty at the Mars base when the demonic invasion hits.
• Flunky Boss:
  • The Guardian of Hell. The Guardian itself is blind, and uses flunky Seekers to see.
  • The Cyberdemon is assisted by mooks that are summoned from time to time. This proves to be his downfall, as killing said mooks fuels the Soul Cube so the main character can use it against him.
• Food Chain of Evil: Some monsters are seen feasting on zombies. Since the last third of the game lacks zombies (or any human corpses) for the most part, it can be assured that demons have eventually eaten all of them.
• Foreshadowing: It doesn't take a rocket scientist to realize a lot of the maniacal laughter throughout the Hell invasion sounds exactly like Dr. Betruger. By the time he actually reveals his hand in the invasion, it's especially blatant as he continuously threatens you that he simply never even cared to hide his voice or pretend he was anything else.
• Friendly Fireproof: Averted. Enemies can hurt each other, although there's no infighting. Notably, if you get between an ally Sentry Bot and its target, the Sentry Bot's machine gun can hurt you too.
• Game-Breaking Bug: Most newer (as of around 2009) systems at best ran the game on degraded quality, or, at worse, flat-out refuse running the original game and its expansion out of the box, forcing either only playing the BFG Edition, tweak the settings or use a source port.
• Game Mod: Being a Doom game, the modding community took to it almost immediately after release and a following continues to this day, if not nearly as large as the originals.
  • Mere days after release, fan Glen Murphy released a mod called "Duct Tape", fixing the oft-criticized "no duct tape on Mars" problem by putting a flashlight on a few weapons. Ironically, this mod was a much more modest change than the armor-mounted flashlight which id themselves would add in the BFG Edition, since only two basic guns — the shotgun and machine gun — have lights added in "Duct Tape", and both have a much narrower beam than the standalone item, while the BFG Edition allows for use of the regular flashlight at all times.
  • One of the most well-known total conversions, The Dark Mod, uses the game's engine to modernize Thief: The Dark Project. The mod eventually 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. It also has a compatibility patch for Resurrection of Evil.
  • Doom 3: Enhanced Edition is a mod that aims to give the game and its expansion packs some quality-of-life improvements, visual and audio touch-ups, and a some gameplay tweaks without deviating from the game's original mechanics.
  • dhewm³ is a source port of Doom 3 that provides bugfixes, support for modern resolutions without editing configuration files or using the developer console, implements Carmack's Reverse for its shadow rendering, restore EAX support for positional 3D and surround sound capabilities through OpenAL, controller support through SDL2, and improved support for 64-bit operating systems (though requires compiling from source code). Modding support, however, is limited to non-DLL based mods unless the mod's developer can port it to the new engine.
  • CstDoom3 is an engine overhaul of Doom 3 that adds new options, quality-of-life improvements, optional gameplay tweaks, bugfixes, and also includes Carmack's Reverse. It also has a version for the BFG Edition that gives players the ability to restore some of the cut content from the original game, the option to re-instate the original flashlight mechanics or use a hybrid of the two, bring the game's ammo distribution back to the original values, and a built-in Achievement System.
  • Killatomate's Realistic Weapons mod tweaks how weapons handle in the original Doom 3 and Resurrection of Evil and making them feel, well, 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.
  • Perfected Doom 3, on top of graphical improvements and a shoulder-mounted flashlight, adds new alternate fire modes for the weapons (the pistol and super shotgun can be dual-wielded, machine gun's ammo display doubles as a scope, plasma gun fires a stream of damaging gel, etc), allows you to carry medkits and berserk packs in your invetory, and allows you to summon a monster called the Soul Knight to fight alongside you.
  • Overthinked Doom 3 emphasizes the Survival Horror aspects more. The weapons feel more powerful, but the amount of ammo you can carry has been reduced, and the machine gun and plasma gun have both had their ammo capacity reduced to 30 rounds. Enemies are also smarter and tougher, which makes combat a much more tactical affair.
  • 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 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. Episodes 2 and 3 were planned at one point, but were scrapped during development. On the plus side, it has some awesome remixes of the first episode's soundtrack.
  • HardQore2 is a mod that turns Doom 3 into a side-scrolling run-and-gun platforming game à la Metal Slug and Contra. It was remastered in 2021 under a new name, Doom 3: Hard Corps.
  • Rivensin is a total conversion that turns Doom 3 into a third-person action game featuring melee and spell-based combat in addition to having access to ranged weapons.
  • The Lost Mission expansion from the BFG Edition was backported into the original Doom 3, allowing those who prefer the original version to experience the levels cut from the final game.
  • The VR mod for the BFG Edition, as the name implies, allows you to play the game with a PCVR headset.
  • The previously mentioned Quest 2 mod by Team Beef allows the game to run on a completely different VR platform, the standalone Oculus Quest 2.
• Game Within a Game: There's an arcade game title Super Turbo Turkey Puncher 3 where you punch lots of turkeys. Getting a high score earns you an achievement.
• Gas Chamber: An entire level is made into one of these, and you have to find the ventilation switch.
  Dr. Betruger: There's nothing left for you but a slow death as your lungs fill with toxic gases.
• Gatling Good: The chaingun makes a return, and unlike the relatively anemic version in the classic games^*the best analog for which is the Machine Gun, it's a rapid-fire powerhouse on par with the Plasma Gun in damage, but relatively inaccurate and with scarce ammo for the first half of the game. Chaingunners also make a comeback.
• Glass Cannon: The Tentacle Commando is difficult to shake off, but barely has more health than other regular zombie enemies.
• Goodies in the Toilets: Items such as health, armour and armour shards are often hidden in bathrooms around the game.
• Guide Dang It!: There are two special storage cabinets sent from a company called "Martian Buddy" that contain free stuff for personnel, and the codes to them are nowhere in the game. To find the code, you actually have to go to the website www.martianbuddy.com ^note As of 2012, the website isn't even online any more outside of the Wayback Machine. Luckily, the code is still available in FAQs.. One of these allows you to obtain the chaingun early, which is a big help for clearing out the tougher enemies at the end of Alpha Labs Sector 2 on higher difficulty levels.
• Hell on Earth: Dr. Betruger's ultimate plan is to bring the demons to Earth.
• Helmets Are Hardly Heroic: Unlike the Marine in the classic games, both the Marine in 3 and the Engineer in Resurrection of Evil go bare-headed. That 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.
• He Was Right There All Along: In the final area, you walk through a doorway into a seemingly empty arena, before finding out you just walked under the Cyberdemon's legs. Either it just likes to stand over doorways and freak people out or the door spontaneously changed its destination.
• Hide Your Children: A notable aversion, as cherubs look like a kind of mutated human infants, although they may be just demons deliberately made to look like infants just for the effect it would have on human enemies.
• Hold the Line: The game often does this with swarms of spiders (Trites and Ticks), such as when waiting for a ladder to drop down.
• Hollywood Darkness: Most of the game is pitch black. The player is forced to use either his gun or his flashlight, but not both at the same time. It was dubbed "the best flashlight simulator ever" and widely ridiculed for being so aggravating. One of the first modifications created for the game was the Duct Tape mod, which removes the misfeature by "duct taping" a flashlight to the shotgun and machine gun.
• Horrible Judge of Character: Seemingly everyone working at UAC (with the exception of Elizabeth McNeil and Elliot Swan), as despite looking rather like Hannibal Lecter, having a name that's German for "Deceiver", and generally reeking of evil, most of the other people don't seem to suspect that Dr. Betruger might be a bad guy.
• Hyperspace Arsenal: By the end of the game, you'll be carrying a handgun, a shotgun, a machine gun, a chaingun, a bunch of grenades, a plasma rifle, a rocket launcher, a chainsaw, a PDA, a flashlight, a BFG whose barrel alone is bigger than a microwave oven, not to mention all the attendant ammunition, which can include fifty or so rockets and several BFG fuel cells the size of your head. If you change weapons while standing in front of a mirror, Doomguy will simply pull the new weapon out of his pants pocket while the previous weapon simply vanishes into thin air.
• Hyperspace Is a Scary Place: Teleporting will result in you seeing a terrifying blood-tunnel filled with screams.
• Idiosyncratic Difficulty Levels
  • 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;
  • 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.
• Improvised Weapon: The flashlight. Since the vanilla version of the game makes it unfortunately necessary to tote the light around in place of a normal weapon sometimes, the dev team was at least nice enough to make it a decent bludgeon, usually taking out former humans in one or two smacks.
• Infinite Flashlight: The only upside of the torch is that it'll never run out of juice in the original Doom 3.
• Insurmountable Waist-High Fence: Although you can jump and crouch in this game (unlike in the previous ones, at least without source ports), you are incapable of surmounting waist-height obstacles such as broken stairs.
• Intimidation Demonstration: During the cutscene at the end of Delta Labs where the two Hell Knights are being summoned, one of them shows off their brute strength by effortlessly grabbing an innocent hazmat scientist who just escaped through the portal and throws him into a wall, leaving a bloody mess on impact.
• It's Up to You: The game puts you in the shoes of a marine who is transferred to Mars for unknown reasons. Everybody on Mars — besides a handful of marine teams and the other four main characters — is quickly wiped out in the breakout of an ensuing demonic invasion. The marine squads and two of the main characters all fail to do anything of value (of the remaining two, one gets corrupted into evil and the other is the Big Bad); the player alone is responsible for stopping the invasion.
• Jerkass: Sgt. Kelly, overlapping with Drill Sergeant Nasty. Many other workers you come across in the beginning are like this, telling you to go away if you try to talk to them. Considering the constant incidents that had been going around on Mars even before your arrival, it's somewhat understandable.
• Jigsaw Puzzle Plot: The audio logs, video disks, and emails shed light on the backstory and the setting as a whole, giving out much more detail than any other form of storytelling in the game. The vast majority is optional, though some logs and emails are necessary to get door codes for progress.
• Jump Scare:
  • Imps love to crouch down behind doors and around corners, just waiting for you to come by so they can lunge at you. The only telltale for that is them sniffing around, which standing Imps never do.
  • Trites have a habit of dropping down on a silk string either in front of your or behind you, or crawling out from behind computer screens.
  • Some areas inhabited by zombies play a long moan of alert alongside a Scare Chord. Doesn't work too well because, well, they're just shambling zombies.
• King Mook: Vagary, the Trite Queen, serves as a Queen Mook for the Trites and presumably Ticks.
• Knockback: Shotgun Z-Secs and Pinky Demons both deliver sizable knockback — the Z-sec bordering on Blown Across the Room — and can result in stunlocking.
• Lampshade Hanging: The rationale for the player being able to acquire a chainsaw is a series of background logs detailing a shipment of chainsaws that were accidentally sent to Mars. The characters writing the logs draw attention to the fact that no one would ever use a chainsaw on the planet. As they say in the game "What the hell are we gonna do with them? Cut down the great forests of Mars??"
• Laser Sight: A laser sight replaces the traditional crosshairs in BFG Edition if you're playing in 3D mode. It's Awesome, but Impractical, as it looks cool, but is absolutely awful to aim with; the laser sways with the weapon, and doesn't actually point to where the gun actually fires.
• Late to the Tragedy: The game has you both early and late to the party; you're there when everything goes to hell (or hell comes to it) but it's clear a lot has been going on before your arrival.
• Laughably Evil: 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."
• Level in Reverse: You have to backtrack to Marine HQ in Mars City after the demons are unleashed, with many doors and stairways blocked off by the damage.
• Life Drain: 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.
• Lightning Bruiser: "Pinky" demons and the expansion-pack-exclusive Bruisers hit hard, can take a decent amount of damage, and are even quick enough to dodge your shots.
• Loading Screen: The game gives a summary/description of the area being loaded.
• Lock and Key Puzzle: Pops up in three different flavors. The most common is restricted-access doors that require a scan for your PDA clearance, and you have to find the PDA of one of the people authorized (which the door's interface panel helpfully provides a list of) to download the clearance and gain access; sometimes, you have to find an actual keycard^*that plays the classic "item picked up" sound of the classic games; and finally, certain areas have to be unlocked by accessing a security terminal.
• Ludicrous Gibs: The shotgun packs enough punch that if you hit a zombie with it at point-blank range, you'll tear all the flesh off its bones, reducing it to a bloodied skeleton. The chainsaw and berserk-enhanced fist have the same effect.
• MacGuffin Guardian: As soon as you step into the room where the Soul Cube was sealed in Hell, a massive dinosaur-like blind demon (aptly named "The Guardian") emerges from a hellish portal and proceeds to engage the nameless Marine, serving as a Puzzle Boss.
• Mad Scientist: Dr. Malcolm Betruger, to literally diabolic levels.
• Meaningful Name: The name of Dr. Betruger means "deceiver" in German; fitting for his status as a Villain with Good Publicity who is one of the most respected scientists on Mars.
• Meat Moss: Some areas are covered with, for lack of a better word, flesh masses that look like turds or tentacles or minced meat. If you shoot them, they sound like you're hitting steel; whether it's intentional or not, nobody knows. Sergeant Kelly mentions them over the radio before you first see them.
• Misbegotten Multiplayer Mode: The guns are poorly balanced for multiplayer, the game shipped with almost no multiplayer modes, and the critical part of the engine was its ability to render quality shadows. Of course, every multiplayer gamer ever turns shadow quality down to get performance. What's worse, Doom 3's own copy protection locked out just the multiplayer modes if not properly activated, which might have factored in on the quick demise of Doom 3 multiplayer.
• Minimalistic Cover Art: While the standard cover as seen above depicts a Hell Knight and Resurrection of Evil depicts a mugshot of the Maledict, 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 pitch-black metal wall.
• Mission Control:
  • Sergeant Kelly serves this role in the main game for the first half.
  • Doctor Elizabeth McNeil fills this role in Resurrection of Evil.
  • The Lost Mission has Doctor Richard Meyer in this role.
• Modern Stasis: 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... and 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 big Mag-Lite style handheld flashlights^note granted, the static transfer power supply is an advancement, but still (armor-mounted with horrible battery life 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. It could be stretched as them being made bulky to prevent damage^note in fact, they do look somewhat like the reliability-focused Caterpillar line of mobile devices, while the UAC would've had their IT department lock them down to a business-use feature set.
• Monster Closet: 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.
• Mook Debut Cutscene: Many of the demons get this, with the exception of a handful. Weirdly, Wraiths get a special introduction cutscene after you've already encountered some with no fanfare.
• Morton's Fork: Combined with But Thou Must! 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 in Mars City, and shut down the array to keep the invasion isolated to Mars. Either choice^note if you obey Sergeant Kelly, then the distress call is sent and Swann gets angry; if you cancel the message, Swann congratulates you for doing the right thing but Kelly gets pissed results in the same end. The only difference is whether Betruger remarks on your naïveté or laments you not sending the call before doing it himself.
• Moving the Goalposts: Whenever you reach whichever location you were previously ordered to go, your squadmates have already gone ahead and your commander will radio you to go someplace else, making it feel as if you were accomplishing nothing in the game. Or rather, nothing beyond killing a lot of zombies and stuff, which is the real point anyway. During the second half of the game, the commander falls victim of Demonic Possession and your only option is to kill him in a boss battle, thus making the feeling of lacking a real accomplishment even stronger, and by that point the only goalpost is to survive until the end.
• Mythology Gag:
  • 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. The player also have unlimited stamina in Hell, allowing the Marine to sprint as much as he wants not unlike the original Doom.
  • Picking up a keycard will chime with the item pick-up sound also from the original Doom.
  • 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.
  • The mini-boss fight against the first two Hell Knights at the end of Delta Labs is a throwback to the fight against the "bruiser brothers" Barons of Hell that served as the bosses of the first episode of the original Doom.
  • The arcade machine at the beginning of the game utilizes the hud and interface from the first Doom game and has the background taken from one of its levels (namely, E4M9 from Ultimate Doom).
  • The walls in Central Processing: Processing Distribution Center look very similar to the COMPTALL texture from the original Doom game.
• No Body Left Behind: Only demons burn away when they die. Zombies are left behind, unless you splatter them. Then they’ll disappear.
• No Celebrities Were Harmed: Dr. Betruger bears a striking resemblance (both physically and in voice) to Sir Anthony Hopkins. In particular, to Hopkins playing Hannibal Lecter.
• No Cutscene Inventory Inertia: Despite carrying an armory's worth of weapons on his persona, Doomguy is never shown carrying anything other than the shotgun or machine gun in cutscenes.
• No-Gear Level: Shortly after deciding whether to call the fleet or not, the main character is teleported to Hell and loses all his weapons, down to his flashlight in the original game. Then you're fighting the big monsters you've been saving rocket shells for with a shotgun and dead ends. When you return to Mars, you lose your weapons again (except for the Soul Cube), but thankfully, you reacquire most of your arsenal right at the start of your return.
• Non-Indicative Name: There is an instance early in the game where the player encounters a unique, fast zombie. This zombie is internally named the morgue zombie. However, the area where you encounter it in is not a morgue, it's an infirmary.
• No OSHA Compliance: Deconstructed. Even during the friendly introduction to the facility, numerous people complain about the dangerous conditions and complete lack of safety standards in their working environment. Somewhat lampshaded by the automatic announcement that the UAC "cares about the safety of its employees". There's a room that is sealed off because radiation levels are too high. In order to pass through this room, you need to play a minigame in which you pick up barrels of toxic waste with a crane and drop them into an incinerator. This is ironically the most OSHA-compliant room in the entire game. The EPA (Environmental Protection Agency), on the other hand, would probably want a word with you. Several PDAs do mention safety measures existing, and failing for "unexplainable reasons" AKA demonic tampering.
• No Sidepaths, No Exploration, No Freedom: Downplayed. Compared to the abstract layouts of the classic games (including Doom 64), the Doom 3 levels are pretty linear, but they still have plenty of secrets, and sidepaths, especially with the optional vaults and PDAs. The Hell levels, especially in The Lost Mission, are a bit closer to the level design of the classic games and can easily feel non-linear on a first-time playthrough.
• Nothing Is Scarier: 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.
• Number of the Beast: There are lockers scattered around that contains items. One of them, however, contains an Imp. The locker's number goes without saying.
• Obviously Evil: Come on, just take one look at Doctor Malcolm Betruger.
• Oddball in the Series: Already a major departure from the classic games in its own time, later sequels would serve as throwbacks to the originals' style, making 3 and its many digressions stand out all the more.
  • The overall tone is far more grim, serious and frightening. Where other Doom games have never shied away from snarky quips, dark comedy and goofy over-the-top violence, 3 plays the scenario primarily for horror, with a heavy emphasis on pitch-black environments, scary sequences, and a plot that's taken dead seriously.
  • Many of the returning monsters have been heavily redesigned, most notably the Cacodemon, Lost Soul and Pinky, which are practically unrecognizable. The only redesign that stuck in future installments was the Hell Knight, presumably because its original design was merely a Palette Swap of the Baron of Hell. Of the handful of new enemies introduced in 3, only the Zombie would return in Doom 2016.
  • The guns, like in real life, have finite clips that need to be reloaded; in all other games, the player can fire continuously until they're completely out of ammo.
  • The player character has a stamina meter that slowly replenishes over time, which is required to sprint, and outside of using Adrenaline power-ups or the Hell levels, depleting the meter cause the player to become exhausted until some amount of stamina is recovered; in all of the other games, the player can sprint freely without any limitations, and in the 2016 game as well as Doom Eternal, the player can also perform quick dashes to get out of harm's way or traverse through levels.
  • There is no automap feature of any kind, forcing players to navigate the levels on their own.
  • Many items are kept in locked cabinets that require codes to open, which the player usually must find by reading or listening to the various Apocalyptic Logs they pick up. While future games retained pickups that add readable story elements, they're purely an optional bonus, with no gameplay component to them.
  • The levels do not end with a statistics screen showing the total amount of enemies killed and items collected. Although there are still plenty of secret areas containing useful items, the player has to find them all on their own, with no way of knowing if they missed anything.
• Ominous Cube: Inverted with the Soul Cube, which is a artifact used against The Legions of Hell and eventually seals the portal to Hell that opened up.
• Omnicidal Maniac: 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.
• Once-Green Mars: A civilization existed on Mars that was destroyed by the Legions of Hell. The exact same legions that are faced by the human space marine protagonist.
• Only Six Faces: There are only a handful of faces for the various human NPCs, which are re-used frequently. This is most noticeable in the opening Scenic-Tour Level, where you can find two guys with the exact same head standing in the same room.
• One-Winged Angel: By the end of Doom 3, Betruger is transformed into a demonic dragon. In Resurrection of Evil, he puts up a hell of a fight with his new powers.
• Oxygen Meter: The oxygen meter is only visible outdoors, and begins depleting when you're outside the inner areas of Mars City. You can even refill it by getting scattered air canisters.
• Painfully Slow Projectile: BFG projectiles are so slow by this game that you can shoot them out of the air before they hit you. This is even how you're supposed to deal with Sabaoth.
• Planet Heck: The Big Bad provides a forceful trip to hell to the main character by activating a portal in the middle of the game. The setting is styled around Fire and Brimstone Hell, and the protagonist has to find a way out while dealing with hordes of demons, and succeeds after defeating the Guardian of Hell and finding the Soul Cube.
• Plot Coupon: The Soul Cube in the base game and the Artifact in the expansion Resurrection of Evil are integral to the plot of both games. They are also very useful in gameplay. The Soul Cube instantly kills any non-boss enemy and transfers all of its remaining health to the player. The Artifact, once fully upgraded, can slow down time, increase the power of your weapons, and make the player temporarily invulnerable.
• Puzzle Boss: There are two such bosses. The first is the Guardian, which is blind and relies on small floating demons in the arena to see, so you have to kill all of them and the Guardian will spawn more, revealing his weak spot for you to attack. The final boss — the Cyberdemon — can only be hurt by the Soul Cube, and the only way to use it is to kill the enemies that constantly spawned around the arena while avoiding the Cyberdemon's rockets. Once you have killed a sufficient number of enemies, the Soul Cube is fully charged and can be used.
• Regenerating Health: Inverted in Nightmare difficulty, where your health constantly decreases by five points every five seconds until it hits 25.
• Remixed Level:
  • You return to Mars City after Hell invades.
  • After returning from Hell, you have to go back through the Delta Labs. This time, you revisit the first, third and fourth sectors, in the opposite order.
• Resources Management Gameplay: In the original Doom 3, you're unlikely to completely run out of ammo, but ammo pickups are small enough that you can't rely on a single weapon (not even the basic machinegun) throughout the game and will need to switch up between the various guns based on your current ammo supply for each. The only gun you're given an excess of ammo for is the shotgun, which is only effective at point-blank range. This is averted in the BFG Edition, which roughly doubles the amount of ammo you get.
• Reverse Escort Mission: Sentry Bots will escort you to a certain point of the map, and in one instance unlocking doors in the way that you can't open yourself. They chew Hell's forces up and spit them out to such a degree that you don't have to lift a finger^note except for making sure no Explosive Barrels detonate near your bot buddy, as realistically they're the only things that can destroy it in the core game when a fight happens and one's with you. The same doesn't quite go for the Resurrection of Evil Expansion Pack's campaign, though, where you're set up against higher tier enemies like Revenants and Commandos in Sentry Bot sections, so you need to get your own pound of flesh to make sure the bot survives to the end. Thankfully it provides a handy distraction for you to get in close with the Super Shotgun.
• Ridiculous Future Sequelisation: A PDA message says "The new Quake-43 game blows my mind."
• Scenery as You Go: In Hell, at one point you're stuck on a floating platform the size of a city block until you kill a bunch of Imps, at which point a bridge creates itself leading to a nearby structure, though that's more an example of "kill all monsters to open the Locked Door".
• Scenery Gorn: 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.
• Scenic-Tour Level: The game does this with the player character's arrival to the Mars base, up until all Hell literally breaks loose. It's one of the few versions of this trope that lets you slaughter your co-workers without consequence, before the big crisis even occurs.
• Schizophrenic Difficulty: The Alpha Labs are probably the hardest area in the game, mostly because you don't have many good weapons and it's filled with hitscanning zombie soldiers. The game gets much easier from thereon until it spikes again in Hell, and then the difficulty starts jumping all over the place.
• Science Is Bad: The company that develops the teleportation device is shown to have also created breakthroughs in energy generation and storage, and is in the process of terraforming Mars. However, lack of grasp on the risks left the researchers unprepared against the forces of Hell, and their CEO goes through a Demonic Possession.
• Sean Connery Is About to Shoot You: Or rather, a Hell Knight is about to devour you on the game's standard cover.
• Second Hour Superpower:
  • The Soul Cube (only on Nightmare difficulty) and the Artifact are second level superpowers, but never really get powerful or useful until a little bit later.
  • The Super Shotgun from Doom II is available in a side room on level 2. If you know the secrets, you can have both the Plasma Rifle and the BFG 9000 before you even hit the 10th map.
• Self-Damaging Attack Backfire: In addition to the standard Splash Damage from the Rocket Launcher, the BFG 9000 not only also has splash damage but can be overloaded and instantly kill you if you charge it up for too long.
• Sequel Hook: After the invasion from Hell is stopped, the UAC reinforcements can't seem to find Betruger anywhere in the facility. Cue the reveal that he's not only in Hell and seemingly in charge of the demons now, but he's become a talking head within a massive dragon's mouth and fully embraced his demonic gifts as he prepares for the next invasion. Cue Resurrection of Evil.
• Sequel Number Snarl: Subverted as this game was a reboot (and later kicked out of continuity entirely), but this game is technically the 4th installment after Doom 64 (5th if you count Final Doom as a standalone game).
• Sequence Breaking: Memorizing some of the security codes can do anything from unlocking powerful weapons early to circumventing an entire PDA hunt.
• Series Continuity Error: Doom Resurrection features a Bravo team survivor fight back against the demons during an invasion, like the original game. But unlike the original game, the game events occur in June 2145, rather than November.
• Set a Mook to Kill a Mook: 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.
• Shield-Bearing Mook: The rarest type of zombie soldier carries a large, bulletproof metal riot shield.
• Short-Range Shotgun: While the shotgun from the classic games had decent accuracy and range, here it has a spread of 22 degrees, meaning you have to literally shove the barrel in the enemy's face for it to have any effect.
• Shout-Out:
  • The logo for the "Super Turbo Turkey Puncher 3" arcade machine is a nod to the logo for Street Fighter Alpha 3 and the game's developer, "Nabcon", is likewise to Street Fighter developer 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 other series to reference it, the basic pistol in the game is clearly influenced by the blaster from Blade Runner.
  • Several parts of the architecture and atmosphere, most evidently the sections involving monorail rides to certain locations where one can observe the environment and background events, are clearly made in tribute to the original Half-Life.
• Shows Damage: Most enemies and NPCs can bleed and leave blood splotches on their faces or body from where they are hit or shot.
• The Smurfette Principle: There is one female employee that you meet in the entire game, and she dies as quickly as she's introduced.
• Spider Tank: There are friendly spider drones in the form of Sentry Bots.
• Stamina Meter: The first game in the Doom franchise to implement this mechanic. In this game, underneath the player's Health and Armor counter, is an orange meter that represents the player's stamina, which depletes as they sprint and it slowly replenishes when they stop sprinting. Picking up an Adrenaline power-up temporarily gives the player unlimited stamina, while in the Hell levels provides unlimited stamina for the entire level.
• Starfish Robots: The sentry bot is a dog-sized construct with a small body and a huge elongated head right on top of it, with no recognizable features if you don't consider its headlight as an eye. It skitters along the ground like a spider with its four three-toed legs, and attacks threats with a machinegun nestled under its chin.
• The Stoic: 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.
• Story Breadcrumbs: The game can be treated as a classic level-based shooter as long as you treat PDA's as parts of a Lock and Key Puzzle. However, if you delve further into them than just for finding door codes, there's a plethora of information on how Mars City was faring before your arrival, including the increasingly bizarre and frightening incidents (people hearing voices, pieces of heavy equipment that activate on their own and cannot be shut down at all, behavioral changes in personnel, and so on) caused by the latent demonic activity invited in by the teleportation experiments. The audio logs and e-mails detail those incidents from the perspective of ordinary workers, oblivious to the satanic nature of the bad things happening around and sometimes to them.
• Stripped to the Bone: Killing a zombie with a sufficiently powerful attack, such as a point-blank shotgun blast or the chainsaw, will literally melt the flesh off their bones.
• Suspicious Videogame Generosity:
  • Every time you spot ammo or health just laying somewhere, you can bet that somewhere behind you a door will slide open and something horrifying will shamble out and make you waste that newly-acquired health or ammo. Often, the monsters are scripted to show up if and only if you get the goods, so more often than not the best strategy for saving ammo is not picking it up in the first place.
  • The last level of the game starts you off in a room with more gear than you could possibly carry! Unfortunately, it's mostly useless, because the only enemies these things will work on in the level are Maggots and Imps, handled easily enough with either the Shotgun or Chainsaw, and which you need to kill in order to charge up the Soul Cube, the only weapon that will work against the final boss.
• Sword of Plot Advancement: On your first journey through Hell, you find the "Praeleanthor", a.k.a. "The Soulcube". It was apparently being used as a portal between Hell and Mars, but it also functions as a weapon that can one-shot every non-boss enemy in the game, including the Vagaries and Hell Knights. It's also the only way to kill the Cyberdemon, the only creature you will find that can withstand multiple Soulcube hits (or any at all, besides Sabaoth).
• Tactical Suicide Boss: 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 summons weak minions that constantly attack you, enabling you to charge up your Soul Cube again and again.^note That actually becomes a problem if the player's running a "corpse stay" mod that negates Everything Fades, as while the bodies are present the demons won't respawn to refill the cube with. The only solutions are to use the console to spawn in demons, or use a second mod that allows the Cyberdemon to be harmed by conventional weaponry.
• Tech-Demo Game: The game has extremely complex lighting that requires either a Geforce 4 Ti 4800 or an ATI Radeon 9800XT, which were the most powerful GPUs at the time of the game's release. Its lighting was complex enough that the original version still looks impressive from the standpoint of lighting and shadow effects, well over 10 years after its release back in 2004.
• Technobabble: The in-game description for the flashlight delves into this, just to say that it's an Infinite Flashlight.
  "UAC Standard issue light source. This model utilizes a static transfer power supply, so battery replacement is unnecessary."
• Teleportation: This is the central part of the plot inthe game, where teleportation is done by moving matter through Hell itself. Satan didn't like the idea of seeing stuff coming in and out of Hell just like that, and next time the people know, the Legions of Hell come barging in through the "teleporters" and start wrecking massive havoc on Mars.
• Teleporter Accident: A PDA audio log details how an electrical short led to a lab chimpanzee being split in half. Literally. Her torso ended up on the destination marker, and her lower half stayed behind.
• Teleporting Keycard Squad: It happens constantly throughout the game, though sometimes the enemies are just hiding behind doors that spring open whenever you grab the item(s); other times, waves of them literally teleport in.
• Ten-Second Flashlight: In the Updated Re-release, the torch becomes shoulder-mounted, but holds even less juice at a time than the headlamp in First Encounter Assault Recon. Fortunately, it also recharges very quickly, enough that flicking it on and off repeatedly means never staying fully in the dark.
• Third Is 3D: The 3 in the title of the game is stylized so as to make the title essentially "Doom cubed", which is interpreted by some as meaning "3D". This one is interesting, as it announced a switch from "fake" 3D using sprite scaling to "true" polygon-based 3D. Depending on how you count them it's actually the fourth or even fifth mainline Doom game, following up the two classic PC games, Final Doom, and Doom 64, but being a reboot instead of being in continuity with them.
• Too Awesome to Use: The Soul Cube does enough damage to one-shot any non-boss monster, refills your health up to 100, and recharges every 5 kills (it even helpfully says "Use us!" once it's charged). While you could theoretically just use it on every 5th monster you fight, most people still save it for things like Archviles and Hell Knights. In an interesting twist, it is the only way to actually hurt the Cyberdemon, although you are given an endlessly respawning stream of low-end Mooks so you can refill the cube.
• Transhuman Abomination: Towards the end of the game, Sergeant Kelly, your commanding officer, becomes Sabaoth, a mutant torso fused to a tank. He also has a BFG 9000, which was stolen from Campbell. By the end, Betruger has become one as well, the final cutscene revealing that he's escaped into Hell and has since transformed into the Maledict.
• Uncanny Valley: This is purposefully done with Dr. Betruger. Between his inhumanly pale skin, his permanent sneer on his dried lips, and his glassy and fishlike eyes, you can tell right off the bat that something is just off about him, and for good reason.
• Unintentionally Unwinnable: 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 further.
• Unique Enemy:
  • In the second level you encounter a "morgue zombie" in the infirmary. It can jog almost as fast as you can when not sprinting, 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, the slightly "fast shambling" type, or the average speed "Bernie".
  • Only four riot shield Z-Secs appear in the base game, all of them in the same level. They do not appear in the original Xbox version.
  • Ticks are only encountered once in the base game, in the Delta Complex after returning from Hell. They do attack in a large swarm, but are never encountered again until Resurrection of Evil.
  • The Xbox version features a single crawling Imp that appears in Delta Labs Level 3 South. The crawling Imp is a variant of the Imp that is unused in the PC version but can be spawned via console.
  • The Hell level has Imps and Hell Knights with unique "charred" skin which they do not have on all other levels.
• Unexpected Gameplay Change: If you decide to activate the EFR system in Alpha Labs 4 as opposed to extending the service bridge, what follows is an extensive platforming section through well-lit environments, with very few fights inbetween.
• Unlockable Difficulty Levels: After beating the game for the first time on any difficulty, players can unlock Nightmare difficulty, but if the player know their way around command-line arguments or changing a certain game setting in its config file, they can unlock it immediately without the work.
• Unusable Enemy Equipment: Former humans' guns can be picked up for ammo, as they're the same as yours (even the Commando's chaingun). In fact, the way you get the machinegun if you didn't open the locker at the end of the second level is to grab one off a Z-Sec enemy. However, you can't pick up wrenches or additional flashlights from civilian zombies that wield them.
• Updated Re-release: 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 of The Lost Mission, all with improved lighting and rendering, support for 3D TV displays, native ultrawide and high refresh rate support (the original game needed a fan-made patch for ultrawide resolutions and doesn't natively support refresh rates above 60 Hz; a later update in 2023 for the Steam and Microsoft Store versions raises the limit to 240 Hz), a new (though optional) checkpoint system, re-tooled gameplay elements (e.g. less enemies to battle, shoulder-mounted flashlight, more plentiful ammo), 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. The 2019 version of Doom 3 on 8th generation consoles bumps up the BFG Edition's visual quality and resolution up to 1080p on the base systems and 4K on the pro models while restoring the environmental lighting comparable to the original 2004 version of Doom 3.
• Video Game Cruelty Potential: All of the survivors you meet can be straight up murdered either for giggles or to charge the Nightmare mode item; you can even do this before the demonic invasion begins. 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 as the scientist realizes what is about to happen to him^note In the BFG Edition, this one gets you an achievement; spare him, though, and you'll get access to a room with still-rare-at-that-point Chaingun ammunition and a PDA essential to get the BFG much later on.
• Video Game Demake:
  • Ultimate Super Doom 3, which brings the weapons and monsters from Doom 3 into the classic Doom games.^{IMPORTANT NOTE}This mod needs a very deprecated version of GZDoom to work and isn't compatible with newer versions of the port.
  • DBP 28: Fear and Loathing is a short campaign inspired by Doom 3 in the original. But unlike Ultimate Super Doom 3 that needs an advanced source port^note specifically GZDoom and advanced scripting thereof to work, Fear and Loathing — other than needing to remove static limits — runs entirely on the original id Tech 1 engine. Even the flashlight works, by means of using the action of the muzzle flash effect at a constant rate to brighten up the screen.^note Incidentally, "hacking the muzzle flash" is exactly how the Duct Tape mod for Doom³ works to project the flashlight beam.
• Video Game Setpiece: Although the classic Doom games (including 64) predated this phenomenon, this game included several setpieces along with more traditional Cut Scenes.
• Villain-Beating Artifact: The original version requires that the player use the Soul Cube to take care of the Cyberdemon. This was changed both in later patches of single-player mode and in co-op mode.
• Villain with Good Publicity: Dr. Malcolm Betruger is quite well-respected throughout the Mars base, with only a few of his direct subordinates having any suspicions of his intentions before the invasion starts.
• Voice of the Legion: The villain Malcolm Betruger, who has somehow become corrupted by the demons of Hell, spends the second half of the game taunting the player about how Hell will reign, how your soul will be his etc, in a typically villainous, nasal voice. However, when you reach the final boss at the end, you suddenly hear Betruger again: "So you made it this far?" in a cavernous, echoing roar. It's quite clear that something rather fundamental has changed about Dr. Betruger, but we don't learn what until the final scene in the game. The souls which created the Soul Cube also have this.
• What Happened to the Mouse?: The ending cutscene, as well as the opening cutscene of Resurrection of Evil, establish that the Marine was the one and only survivor of the invasion, which leads one to wonder what happened to the small handful of other survivors that you find throughout the game, most of whom who were still alive and well at the time you left their company. Curiously, this is contradicted by the BFG Edition's Lost Mission.
• Who Forgot The Lights?: The game is rather infamous for being very dark. In reality, this is mainly to show off the game engine's ability to render complete pitch-black darkness; in-universe, it's explained by a combination of the UAC cutting corners on lighting and teleporter experiments wreaking havoc with the power grid, with the manual stating that's why all security forces are required to carry a flashlight. After the demonic outbreak starts, lighting that barely worked properly before is totally trashed, and the flashlight becomes the only reliable light source until the end of the game.
• Womb Level: Several of the hellish sections are covered in living flesh. Sergeant Kelly states before you come across it that "some unidentified growth" is taking over the base. It's especially bad in the Delta Complex, where so many flesh growths have broken through corridors, doors and halls that it becomes difficult to navigate; Sector 3 in particular requires taking detours through vents or outright teleportation to proceed.
• Wrong Genre Savvy: 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. Too bad that that is exactly what Dr. Betruger wants, so as to use those ships to have the demons invade Earth. It ultimately doesn't matter because if you don't, he will send the transmission himself anyway.
• You Don't Look Like You: The Demons only somewhat resemble their counterparts from the earlier games in the series. Imps have many eyes, Pinkies are blind with mechanical rear legs, Revenants have transparent flesh, and so on.
• Zombie Gait: The game features a wide array of zombies. A few are faster than the rest (speed shambling) and usually either wield chainsaws or have been set on fire, but otherwise exhibit similar behavior. Zombie Commandos move quickly (no shambling), don't moan or grunt, and often wield guns and hide behind cover; however, they're closer to actual demons than zombies, given that they burn away after dying.

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Doom 3: Resurrection of Evil contains examples of:

• Abnormal Ammo: The Grabber has a limit to how long it can hold something, and it can pick up organic matter non-lethally.
• Absurdly Spacious Sewer: About two-thirds into the fifth Erebus level, players must make their way through 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 helmet mechanic was completely removed in BFG Edition, however.
• Ambiguous Ending: Did the Marine and McNeil both die at the end and are living in the afterlife to honor their sacrifices?
• Artifact of Doom: The Artifact was created by the forces of Hell to counter the Soul Cube the martians created to fight them, and to act as a key many years later when humanity has colonized Mars. It gives the wielder the powers of super speed, One-Hit Kill, super strength and invulnerability but it has to be fuelled by human souls and as long as it's on the living world, Hell will always have a way there. The only way to make sure that Hell won't conquer Earth is to destroy The Artifact in Hell for good... which Betruger will not tolerate.
• The Berserker: What the Artifact turns the Marine into with the appropriately named "Berserk" upgrade garnered from defeating the Berserk Hunter.
• Bittersweet Ending: A common interpretation of the vague ending of Resurrection of Evil. By the climax, every single person besides the Engineer Marine and Dr. McNeil is implied to be dead. McNeil orders the marine to shut down all the core systems in Phobos Labs, 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.
• Bullet Time: 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.
• Catch and Return: 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.
• Curse Cut Short: At the beginning, one of the radio transmissions gets this:
  "We got a cluster— [static] over there!"
• Dark World: Late in the game, McNeil states that the Delta Labs area is phasing in and out of the Another Dimension, Hell, creating a more tangible Dark World where the two intersect. In fact, the penultimate level has you going through previously-visited areas as reality constantly shifts back and forth every couple of seconds.
• Dragons Are Demonic: What's left of the Big Bad has fused with a giant demon dragon in the expansion, and given that said demon dragon guards Hell itself, it's as literal as you can get.
• Earn Your Happy Ending: Even at the possible cost of their own lives, McNeil and the Engineer manage to defeat Betruger and seemingly halt the invasion for good.
• Emergency Weapon: In addition to retaining the fists and the flashlight, the expansion adds the Grabber, which can be used to grab barrels, crates, most enemy projectiles and even some small enemies themselves, and fire them back at the sender.
• Expansion Pack: Resurrection of Evil is a direct sequel to Doom 3's story that adds to the base game a five-hour campaign, three new weapons, a few new enemies, and a final boss. The BFG Edition also includes an additional mission pack titled The Lost Mission, which is a couple hours long but adds no new content besides maps.
• Fade to Black: After the Maledict is killed, the game fades to black in BFG Edition of the game.
• Fade to White: Conversely to the above, the game fades to white after Betruger is slain.
• First Day from Hell: You're part of a team investigating a faint signal on Mars. You touch an ancient artifact, and your teammates are vaporized as hell once again breaks loose. Of note is that you started the invasion this time.
• Hoist by His Own Petard: The Grabber is perfect for catching demonic projectiles and sending them back at your attackers, killing most of them in one or two hits. In fact, a random marine you meet in the very first level dispatches an imp in that exact way before passing the Grabber over to you and succumbing to his injuries.
• The Internet Is for Porn: A worker named James Owens in the Phobos labs was having problems with his computer running poorly and e-mailed a technician to find out what was wrong with it. He gets a reply from the technician who found on about Owens browsing through porn sites and may have attracted a virus from there.
• Karma Houdini Warranty: After having gotten away at the end of the original game (and turning into a powerful demon in the process), Dr. Betruger is finally killed here.
• Lightning Bruiser: The Engineer Marine is this in 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.
• Mission-Pack Sequel: Well, the original PC release is just a mission-pack, but the Xbox version was released as a standalone game, making it this.
• Nice Job Breaking It, Hero: 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. Oops. To be fair to the Engineer, however, Hell and the Maledict/Betruger in charge were already prepping the invasion to seize the Artifact to begin with and merely capitalized on the opened-portals opportunity with glee. As it turns out, the Artifact ended up in the perfect hands for slaying the hordes and finishing the fight, so him breaking everything ends up being the only reason why he can win.
• Nigh-Invulnerability: The Engineer Marine gets this through the Artifact once it absorbs the power of the Invulnerability Hunter.
• Nostalgia Level: A couple of these show up.
  • The very starting area is heavily based on the last levels of the original Doom 3, taking place inside a primary excavation facility.
  • Erebus Facility in general has several thematics to it: an excavation site similar to Caverns, Erebus Dig Site and Artifact Storage both inspired by Site 3, Erebus Control having similarities with Mars City Underground, Erebus Research and Erebus Station both based on Recycling Facility and so on.
  • Phobos Labs are a mixture of Alpha and Delta Labs facilities, plus some elements of Enpro Plant thrown in.
  • Delta Labs Unknown is a remake of the eponymous Delta complex seen in Doom 3, except that the whole area is ruined and constantly shaken by dimensional shockwaves. For some reason, the demonic flux managed to spread its influence to the Mars City administration, also from the main game.
• Quad Damage: The second power gained for the Artifact is Berserk, a massive damage boost while the Artifact is in use.
• Sawed-Off Shotgun: The Super Shotgun you find in Sergeant Kelly's office has a noticeably short barrel for what is supposed to be a hunting shotgun.
• Short-Range Shotgun: The Shotgun and Super Shotgun. Though still short ranged, the Super Shotgun is actually a bit more accurate than the regular shotgun since there's a larger central grouping of shot.
• Shout-Out: One of the PDAs you can find belonged to Nathan Reynolds.
• Smashing Hallway Traps of Doom: One appears right after you gain the ability to slow down time in respect to yourself. It more or less serves as a tutorial for using that power.
• Suspicious Videogame Generosity: In the final room, before the final boss, you are treated with a lot of items and powerups. Randomly throughout the game you can use the souls of corpses to give yourself invulnerability/damage buff/speed increase, and you find these corpses littering most of the stages, however you find almost six in one place, which is three more than you could possibly hold. Then you find out the reason behind it - the final battle against Betruger lacks any means to replenish your health.
• Tagline: "True evil never dies"
• Tennis Boss: The first boss is one of these. For that matter, you can kill virtually every other (non-boss) enemy in the game with one hit in this manner, thanks to a grabber. Even the fearsome Hell Knight will go down in just three of his own fireballs thrown back at him, and more often than not the game allows you enough space to pull this off.
• Too Awesome to Use: The trademark Artifact (aka Heart of Hell) from the expansion Resurrection of Evil can stop time, turn the player invincible, and boost the damage of their weapon all at once depending on how many of the Hunter bosses they've killed. It's such a cool effect that the player is commonly tempted to conserve the artifact's energy and rarely use it, even though it can be recharged everywhere. Then again, its power depends on human souls stolen from corpses, so not using the artifact can fall into Video Game Caring Potential.
• Unique Enemy: The Bio-Suit zombies only appear in one section of the game, which is the waste tunnels. Interestingly, the same applies to Maggots who were quite common in the original game.

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Doom 3: The Lost Mission contains examples of:

• Art Evolution: The one speaking role character you encounter, Dr. Meyers, is motion-captured and far smoother in animation than anything in the main two campaigns that used hand-animated keyframes by comparison.
• Break Out the Museum Piece: The double-barreled shotgun in this campaign is found inside a glass case in the office of a UAC scientist, who says in his PDA emails that it was just a gift from his brother for him to put on display, and he has no idea if it actually works. Conveniently, once the player retrieves it, it functions perfectly and fits the shells that they already have.
• Construction Catcalls: A found PDA that belonged to a female UAC scientist includes an audio long in which she complains about the nearby construction workers' unprofessional and inappropriate behavior, which includes sexually harassing her and the other women.
• Cut and Paste Environments: 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.
• Cutting Corners: One of the PDAs you can find in the under-construction Exis Labs belonged to a contractor hired to install the facility's windows, who brags in his audio log about finding a brand of glass that was much cheaper and easier to access than the brand he was initially asked to use, thus ensuring that he and his crew could earn their completion pay as soon as possible. He complains that the building's architect tried to stop him, claiming that the windows would now be too weak and prone to leakage, but he went ahead with the plan anyway, and declares that he is so confident in the windows' sturdiness that he will fire a rocket launcher at them to prove beyond a doubt that they'll never break. Sure enough, the very next room the player enters is a disheveled half-built room which loses all air supply once the windows get blown out by a Revenant's rocket.
• Downer Beginning: The Lost Mission starts where Bravo Team was ambushed by demons from the main campaign, followed by a marine's lifeless body being dragged through a blood-soaked duct. The fan-made campaign port for the original Doom 3 expands on the opening where the Bravo Marine who was dragged through the duct finds mysteriously himself alive despite being dragged around by a demon, and then the game proceeds from there.
• Earn Your Happy Ending: In contrast to the Downer Beginning entry above, the ending is much better. Betruger's attempt to invade Earth through the Exis Labs teleporter is thwarted while the Bravo Marine and Dr. Meyers are both rescued, despite the amount of crap each had gone through.
• Hero of Another Story: Dr. Meyers and the Bravo Marine manage to destroy a long-range teleporter before the Doom 3 marine even completes his mission.
• Lower-Deck Episode: One which is viewed from the perspective of the last surviving Bravo Team member (who was dragged through the vents before the Doom Marine could connected with Bravo). The story runs in parallel (though they never cross) to the main story, with the Bravo Marine trying to close a prototype portal in the old Exis labs near Mars City, as the demons could use this as a "back door" to Earth.
• Mythology Gag: One section of the penultimate level in Hell is set in a twisted cathedral with an ornamental bust of a horned demon hanging from one of the walls, which spawns Forgotten Ones directly from its mouth. Although the demon only bears a light resemblance to Doom II's Icon of Sin, its releasing monsters from its mouth is no doubt a reference to it.
• Unbroken First-Person Perspective: Unlike the base game and Resurrection of Evil, The Lost Mission never leaves the player character's perspective after the opening cutscene.

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"Marine? Marine, welcome home."