"Over the centuries, mankind has tried many ways of combating the forces of evil... prayer, fasting, good works and so on. Up until Doom, no one seemed to have thought about the double-barrel shotgun. Eat leaden death, demon..."
id Software's follow-up to Wolfenstein 3D was Doom, which represented a big step forward in the art of texture mapping, and an even bigger step forward in videogame violence. It follows the story of an unnamed Space Marine posted to the Union Aerospace Corporation's base on Phobos, one of the moons of Mars. When teleportation experiments between Phobos and Deimos cause Deimos to vanish and a horde of grotesque monsters to invade the Phobos base, our hero is the only human left alive between the two bases. He fights his way through the creatures in search of a way off Phobos, finding himself transported instead to Deimos, now residing in the creatures' homeland, which turns out to be none other than Hell itself.The release of Doom (1993) was met with unprecedented controversy regarding its content. Not only was there a very high amount of frank Satanic imagery (albeit all cast in a highly negative light), it was filled with graphic depictions of zombies and monsters being blown apart, eviscerated, shot to pieces and generally disintegrating into piles of gore. Gameplay was extremely gung-ho — the makers noted that the manual could have simply read, "If it moves, kill it" — and encouraged the player to attack with reckless abandon, using such implements as chainsaws, chainguns and the originalBFG, a massive weapon which could reduce an entire room of monsters to viscera. Even the player's own face, shown near the health counter as in Wolfenstein, became battered and bloodied with damage.Also, whereas Wolfenstein's fortresses all had identical lighting, Doom featured variable lighting, including flickering and glowing lights, adding to the game's atmosphere. The game also introduced the idea of multi-player death matches and co-op missions in a modern FPS, with its developers fully expecting Doom to be the biggest cause of decreased productivity in IT companies the world over in 1993. And they were right.Followed by Doom II: Hell on Earth (1994), which saw the demons invading Earth, which was a huge success. In between Doom II and 3, Final Doom was released the same month as Quake. It was identical to Doom II, but came with two different Expansion Packs: TNT: Evilution, created by the third party modding group TeamTNT (originally intended to be free until id struck a publishing deal with them;) and The Plutonia Experiment, made by two members of the group in four months' time, generally considered the hardest of the official packs. (Final Doom also included a 32-bit Direct X version of the Doom engine, making it the only way to play classic Doom on many modern 64-bit Windows machines, besides virtual machines like DOSBox or the many source ports.)A decade later, Doom 3 (2004) was released. The third installment, which was a reboot rather than a sequel, breaks with the first two significantly, with a dark, oppressive tone much more akin to a Survival Horror than anything. It was this incarnation on which the movie was based. This was followed by the expansion pack Resurrection of Evil, set two years later. The game was remade in HD, compiling the first two games with it, in addition to adding another eight levels to its campaign. Furthermore, you can actually wield a flashlight and a gun at the same time. This compilation, titled the BFG Edition, was released in October 2012.At Quake-Con 2014, id Software revealed Doom, a reboot of the franchise, known to most fans as Doom 4. To prevent any leaks, the only people who attended the convention were allowed to see gameplay of Doom. Descriptions of the footage mentioned that Doomguy will be able to double-jump, and be able to perform finishing moves, such as tearing an enemy's heart outthen forcing them to eat it, almost akin to Brutal Doom. Doom used to be known as Doom 4 when it was revealed in 2007, but the game went through Troubled Production, so id decided to revive it.Doom has been ported to many many console systems over the years. The PlayStation and Sega Saturn versions combined levels from both Doom and Doom II alongside a large number of unique missions; more original levels were released in a sequel entitled Final Doom. There was also Doom 64 for the Nintendo 64, which was an entirely new entry in the series and probably more of a Doom 3 than the actual Doom 3 was (it was released years before, ran on a modified version of the original engine and continued the story of the first two games). Doom's source code has been released, and, at this point, almost anything with a CPU in it — many cameras and music players, some watches, several appliances, even a graphing calculator has been shown to run it for about half a minute before crashing — has had a version of Doom released for it. The game used a creepy and distinctive sound effect for doors opening, which has been re-used in many Speculative Fiction series for all sorts of things.Also, a comic for Doomwas made at the height of the dark age. It's hilarious, probably intentionally so. We hope.There was also a series of novelizations by Dafydd ab Hugh and Brad Linaweaver. Four in all, the first two—Knee Deep in the Dead and Hell on Earth—were based on the first and second games, respectively. The final two, Infernal Sky and Endgame, went their own direction with the plot. These novels have a small cult following. There are also two novels based on Doom 3 by Matthew Costello, who also wrote that game's script.As for other products in the franchise, there are two cell phone-based RPGs, an iOS-based Rail Shooter, and a board game with expansion pack.
100% Completion: The classic games has percentage counter for how many monsters were killed, items, and secrets found in each level.
Abandoned Mine: "The Abandoned Mines" in Doom II. Granted, it doesn't look much like actual mines (then again, no level in the classic Doom games looks like anything) and it's supposed to be located in Hell, but it does have areas that look like giant underground excavated caverns which probably inspired the level design of Doom 3.
Actionized Sequel: While Doom I is fast-paced, it is generally willing to have scary moments as shown with several fights through a maze filled with Pinkies and imps while the lights flicker on and off. The second game goes for the "EXPLOSION TIME" brand of fun people associate with the series. The third slows things right down and adds in more Survival Horror elements to the mix.
It is also inverted before Doom 3 showed up: in between Doom II and Doom 3, there was Final Doom and Doom 64. Final Doom was a Doom II style death orgy that had two whole level packs. Doom 64, however, is a horror game with just this spooky droning soundtrack.
Also, the novelizations are the only time "Doomguy" is given a proper name (for those wondering, it's Flynn "Fly" Taggart for the classic series novels, and John Kane for the Doom 3 novels). Word of God is that the games' protagonist is deliberately not given a name because it's supposed to be you, the player.
Always Accurate Attack: The arch-vile's attack will always hit the target unless it leaves the line of sight before it finishes. Only the marine can effectively dodge it. Partial invisibility won't cause it to miss, but does affect the knockback direction.
Always Chaotic Evil: The demons all have nothing but malicious intent towards everyone and everything around them, even other demons
Ammunition Backpack: As a power-up. Not only does it give you one of each "small ammo pack" (one pistol clip, four shotgun shells, one rocket, and one 20-volt energy cell), if it's your first, it doubles your ammo-carrying capacity (You can carry 400 bullets instead of 200, and so on).
Ancient Astronauts: In Doom 3, 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.
And I Must Scream: Some crushing floors in the first two games only crush, they never release. If you let yourself be smashed by these and happen to have enough health, you'll remain trapped alive in concrete. Have a nice stay if it's multiplayer and no one else can find and kill you to release you. Thankfully, a rather rare bug.
Arm Cannon: The Cyberdemon and the Mancubus, and the Bruiser in Doom 3's Resurrection of Evil.
In Doom 3, the BFG isn't so much wielded like a gun as it is worn like a giant glove of death. The only one who actually carries the BFG is Sabaoth/Sergeant Kelly.
The Artifact: The computer screens in the star textures contain the text "Tei Tenga" left over from Tom Hall's Doom Bible where the game was planned to be set. After Tom was voted off the island the game moved to Mars' moons.
Artifact Mook: When you add up all the bodies, the extensive bloodstains, the skeletons, the zombies and the Lost Souls you fight in Doom 3, there seem to outnumber the human population in an area quite a bit.
The Artifact from Resurrection of Evil, which is a large heart with bits of metal attached.
The Unmaker from Doom 64, apparently carved from Demon's souls.
Also the Soul Cube from the original Doom 3 although that was created to defeat the demons, rather than by them.
Artificial Brilliance: In Doom 3, the enemy's combat A.I. is very simple, but their path-finding A.I. is actually remarkably well-done; if you use an elevator or ladder to escape from a charging enemy, they can actually circle around the entire map to make their way to your new location. This is only noticeable if you go out of your way to toy with the A.I., however.
Artificial Stupidity: It doesn't matter if a fellow monster is in the way, all monsters will start attacking upon sight of the player, and if their attack connects to a fellow monster, they'll turn on each other. Players who are out of ammo will quickly learn to start triggering in-fights.
Ascended Glitch: Oh, wow. Lots. Most of them have been used and abused for speedruns and map-making.
Similarly, the shimmery "hall of mirrors" effect that occurs when a texture is missing has been adopted by some level designers to create deep water. It will still glitch if your view is below the water level, however.
Also the "voodoo doll" bug, which can be easily created by placing two different start points for a single player. Clever mapmakers have used this bug to create traps which can teleport a player into another copy of himself, resulting in a recursive Tele-Frag (MAP30 of TNT: Evilution is an example). Voodoo dolls under triggered crushing ceilings can also be used to cause player deaths wherever the mapmaker wants; for example, simulating bottomless pits by triggering the ceiling if a player falls into one.
Because the first two Doom games aren't true 3D, a rocket's splash damage isn't a sphere as might be expected; it's a cylinder of infinite height. This bit of questionable behavior, combined with actors being infinitely tall as far as collision is concerned, is what allows you to damage Doom II's final boss.
It is possible to mess with sectors and sector references to create an "invisible staircase" effect, which was best demonstrated by a map called UAC_Dead. This in fact abuses the same glitch as deep water effect above, just the water doesn't need some of the set-up needed for bridges.
If you trigger an action to move the floor up, but the target height is lower than current height, then the floor will move instantly (and the other way round, if floor should be moving down but the target height is higher, it will move instantly too). Combined with "invisible bridge" effect above, this allows for a fake 3D bridge which can be passed over and under, by moving the floor depending on where the player is. This is used in some custom maps.
It is also used heavily in Doom 64 to create bridges and tunnels
In Doom II, The Pain Elemental will spawn up to three Lost Souls when it's destroyed, in a triangular formation.
However, if you let it live, it'll continually spawn them. Get a Pain Elemental into a Let's You and Him Fight with another monster, and it'll spit the things like missiles. (Presumably, because if it just kept spawning them, the programming's not quite up to letting these new Lost Souls attack the monster that hit the Pain Elemental, not them.)
In the "Doom II RPG" for mobile devices, the Spider Mastermind will explode into three Arachnotrons.
A.I. Is a Crapshoot: Zig Zagged in Doom 3's backstory. Sentry bots are powerful fighters and efficient guides whenever you see them, but there were at least two instances where they became a threat to innocent personnel before the invasion. One seemed to come from an error during the system booting, the other because of a worker's simple refused clearance. In both cases, the reporter vehemently questions the bots' artificial intelligence and excessive firepower. Thankfully, they never attack the player in actual gameplay.
A-Team Firing: Normally, monsters fire directly at the player, allowing the player to dodge. If you collect the Partial Invisibility power-up, enemies will fire wildly in your general direction (and miss more often than not.) Ironically, this can actually make it harder to avoid getting hit sometimes if you pick up a bad habit of dodging projectiles or if there are a lot of enemies in an area, because you can accidentally dodge into one of the stray ones.
Attract Mode: Doom and Doom II (and their kin) play a demo if left on the title screen for a second or two.
Auto-Save: Many source ports, such as ZDoom or Zandronum, auto-save whenever the player enters a new level, whilst also having the option of manual saves.
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 cr0wn the imp with one shotgun blast. Once you start getting automatic weapons it becomes tolerable, as you can just blast your way through the rest of the game without worrying too much about precise aim thanks to the increased ammo availability of the BFG edition.
The Berserk pack. The healing part is alright, but the Berserk pack also increases the strength of your fists, to the point that you can explode imps and zombies with them. But why would you risk rushing into a horde of enemies to punch them to death one at a time while the others tear you to shreds (fortunately, mouse controls make melee combat much less unwieldy and more feasible.)
Happens to Sergeant Kelly, who gets fused into a tank, and Dr. Betruger, who gets partially consumed by a demonic dragon.
The original Doom games also have plenty of walls in the hell levels appearing to be made of human flesh, faces, or piles of corpses.
Boring Return Journey: The end of Doom II has your character taking the long trek back home after practically destroying Hell.
Boss Arena Idiocy: The final boss of Doom II is a giant invulnerable face in the wall of an arena which spawns endless monsters from the hole in its forehead; its only weak spot. You can shoot rockets into the hole to kill it, but such a task would be impossible if not for the arena providing a convenient elevator that reaches the height of the brain hole.
However (even though ports supporting mouse aim do indeed ruin the level), this level is still not all that easy to win: While the elevator rises to ca. the height of said hole, firing a rocket when the player has already reached the top is rather useless since the rocket will hit a spot slightly above the hole and do no damage whatsoever. Therefore shooting the rockets has to be timed precisely. Moreover the process has to be be repeated at least three timesnote as the THING which needs to be destroyed in order to beat the level is only affected by the rockets' blast radius, which is a randomized value, which can render the level a bit frustrating, especially on higher skill levels.
Boss in Mook Clothing: Archviles, Mancubi in Doom 3, Barons of Hell, Hell Knights in Doom 3, Bruisers in Resurrection of Evil. Also, a huge chunk of the custom monsters in ZDoom's realm 667 beastiary.
Swastikas in the E1M4 were changed in later versions to allow the game to be sold in Germany. Also, German versions of Doom II do not contain levels 31 or 32.
The Game Boy Advance ports of Doom I and II had all the in-game blood turned green. Ironically, the SNES port of Doom retained most of the original game's red-blooded violence, with only the Satanic symbols being censored.
The BFG Edition and XBLA version of Doom IIcompletely purges the secret Wolfenstein 3D levels of every Wolfenstein element: No Swastikas nor Hitler portraits, the SS guards are replaced by zombiemen squads, the unique map music themes have been replaced by the theme of MAP05 for both maps and the level names have been renamed ("Wolfenstein" to "IDKFA" and "Grosse" to "Keen").
Brutal Bonus Level: The second secret level of The Plutonia Experiment, "Go 2 It". Oh hell!
You think that's bad? The Plutonia 2 equivalent, unsubtly named "Go 4 It", is the same again... on steroids.
Plutonia Revisited ups the ante again with "Have @ It".
Doom 64's "Hectic" is a very tiny level with a small handful of enemies, but is packed to the brim with dirty tricks and One-Hit Kill traps (the first room of the level is full of power-ups that will kill you if you try to get them, except for two you can only get in a very specific way.)
Cancellation: Only two of the three planned Doom 3 novels were released; the third got canned.
Canon Welding: The cell phone RPGs are in the same continuity as Wolfenstein RPG, which features the "Harbinger of Doom" as the final boss. The Harbinger gets his arm and leg blown off and swears to avenge himself on B.J.'s descendants, becoming the Cyberdemon.
Clothing Damage: As seen in the page image, Doomguy's uniform is heavily damaged in most official artwork. Amusingly, this led to some players thinking that his armor was issued with an abdominal cutout.
The Computer Is a Cheating Bastard: A combination of Fake Difficulty and bastard map-designers, it does not matter how carefully a player clears rooms and watches dark corners as there will always be tiny, function-less, hidden, and effectively-invisible closets containing idle monsters whose sole purpose is to surprise the player from behind.
And, to a lesser extent (at least in the base game), there's the fact that due to the way Hit Scan enemies (i.e., riflemen, shotgunners, etc) are programmed, they will always hit you unless you get behind cover (if they don't miss due to spread), even if they're on the other side of the map from you. While this doesn't matter much in the enclosed spaces of the base game, in some custom levels favoring open spaces, this can get very annoying.
Container Maze: Some parts of E2M2: Containment Area in the first Doom is basically a maze of crates with UAC supplies.
Continuity Snarl: In the end of The Lost Mission, The Bravo Team survivor and Dr. Meyers are both successfully rescued from Mars. This contradicts the opening screen of Resurrection of Evil, where it says that only one survivor (the Doom Marine) was ever found on Mars.
Contractual Boss Immunity: Cyberdemons and Spider Masterminds are immune to splash damage. They only take damage from the rocket itself, not the explosion.
Corrupt Corporate Executive: The UAC and particularly its leadership are explicitly capable of operating outside of all ethical and legal restrictions. They're a rare non-villainous version (for now), in that they are not stupid like Umbrella Corp in believing that unleashing hellish monstrosities is a GOOD idea. The main antagonist, Dr. Betruger, is in fact infamously at odds with them due to his reckless behavior even prior to the game, and the company's two representatives from the top wind up saving the human race if you make the mistake of calling for the fleet. They're also explicitly attempting to help the bizarre conditions on the Mars base as well.
The Corruptible: The Lost Mission clarifies how Dr. Bertruger ended up allying himself with the forces of Hell. apparently, he was already into the occult, and when the teleportation experiments began the demons contacted him in his dreams and offered him vast power in exchange for Earth.
Covers Always Lie: The cover of the first game shows Doomguy holding what seems to be some kind of sub machine gun or small assault rifle, despite the game having no such weapon. It did, however, exist in the alpha — but that weapon was turned into a chaingun during development.
It eventually made its way into Doom 3, albeit with a redesigned appearance.
Critical Existence Failure: Played straight for all enemies. Cyberdemons, Spider Masterminds, and Arachnotrons are more justified with the former launching rockets and the latter two being mostly robotic.
Cut and Paste Environments: It has been noted that many areas in the new "Lost Mission" campaign in Doom 3 BFG Edition are simply made up of rooms from vanilla Doom 3 copy and pasted together.
Damage Discrimination: With the exception of bullets, monsters are immune to their own kind's projectile attacks.
Although they weren't bosses (except for the 'Bruiser Brothers' at the end of the first episode) Barons of Hell were considered to have hit points WELL out of proportion with their actual threat level. This led to the introduction of Hell Knights in Doom II, which were about as dangerous (their plasma orbs and claw attacks did the same damage), but only half as tough.
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 that have played the original Xbox version where the sprint button is mapped to the left trigger.
Darker and Edgier: Doom 3. Definitely darker (har har), but it includes a storyline and several PDAs one can find to expand on how Hellish (har har) UAC became. It also introduces a lot more Survival Horror elements and contains jump scares, and makes combat a bit slower.
Just to amplify the difference, you can take a look at the photo gallery. Guess which ones are made in Doom 3.
Even the original games get progressively darker. Where Doom had most of the game with a soundtrack of rock and metal, Doom II opted for slower, darker, mood setting music. The PlayStation and Saturn versions of Doom and Doom 64 went even further, introducing darker music, and remodeling/revoicing the demons to appear far more intimidating. Some parts of Doom 64 are downright scary.
Dead End Room: the exit chamber of MAP12, though it doesn't prevent you going forward, it only prevents you re-entering the rest of the map. See also And I Must Scream above.
Deadly Dodging: A major tactic is to slip between enemies (or at least ensure one is between your attacker). If one enemy damages another with a ranged attack or barrel explosion, this results in monster in-fighting (generally resulting in one of the enemies dying.)
Death by Cameo: In Doom II, John Romero's head is the Big Bad (more accurately, the Big Bad's hit-box, and it can only be found using the "idclip" cheat and walking INTO the boss' brain). And the body of the designer of level 24 of the fan-made Doom II level pack Requiem can be seen upside down on a cross in that level.
Degraded Boss: Barons of Hell, Cyberdemons, Spider Masterminds...
The Vagary from Doom 3.
The first two Hell Knights in Doom 3 (a Bruiser Brothers homage) are much stronger than any subsequent specimens.
Demon Slaying: You'd better believe you're going to be doing this a lot.
Diegetic Interface: Probably averted in the whole series (although the HUD could be indication shown inside the player Power Armor), but the trope explicitly appears in Doom 3: when the player is wielding a machinegun, the ammo counter disappears from the HUD and is replaced by a number displayed on the weapon itself.
Difficulty Spike: The first two levels of Episode 4 are the hardest in the first game. Everything after that, though still pretty damn hard, pales in comparison.
Doom II's Level 9, "The Pit", is famous for not having quite enough ammo to destroy all the monsters, even on a full playthrough. Those wanting 100% completion usually had to resort to using the fists or chainsaw for good chunks of the level.
"Hell Beneath", the first level of the new episode from Ultimate Doom, is similarly low on ammo. Even with the level's hidden rocket launcher, killing everything is difficult.
Dual Boss: The two Barons of Hell at the end of the first episode of the original game. They get a repeat in Doom 3.
Dummied Out: A couple of things that were supposed to happen in the original games were effectively dummied out by coding errors:
The "Ouch Face" was an expression for the Doomguy head in the middle of the status bar that was supposed to show if the player received more than 20 damage at a time. In practice, the code was written in such a way that it would only appear if the player took damage and gained at least 20 health during the same tic, something that was extremely unlikely to occur without the player actually trying to make it happen. The "Ouch face" is fixed in many source ports (such as, Boom, ZDoom)
The message "picked up a medikit that you REALLY need!" was supposed to appear if the player had less than 25% health when they picked the kit up. Unfortunately, the code checks the player's health after applying the health change for picking up the medkit, meaning it is physically impossible for the player to have less than 26% health; as a result, the message is never displayed at all (this is also fixed in source ports like ZDoom).
There was also the BFG. The classic BFG is probably the most complicated and illogical weapon ever put in an FPS, largely due to it holding over all of the mechanics from a scrapped alpha version of itself. This "billion fireballs gun" fired a ragged burst of 40 projectiles and was scrapped because it "looked like Christmas" and slowed the game to a crawl. The Doom BFG might appear to just fire a big ball that does splash damage, but it actually does this:
After a delay of just under a second, the BFG fires the green energy ball.
On impact, the projectile deals a large amount of direct (not splash) damage to whatever it hit.
The BFG's invisible mechanics come into play now. The weapon fires a spread of 40 hitscan "traces" (or "rays") evenly distributed across a 90-degree arc pointing in the direction the BFG ball was fired in, from the player's current position, with each ray dealing 15d8 damage. Coupled with the average damage of impact being 450 damage, the average damage of the BFG (with very little deviation, due to the 601 dice rolls) was 3150 damage. This is 150 more health than the final boss of Doom has.
Most people are not aware that you can kill someone with the BFG with your back to them after firing it in a totally different room.
Initially, an Easter Egg game of Asteroids was to be accessible from the computer map, but this was almost entirely cut. (Some references to deleted files remained in code.)
Another piece of code that was dummied out was intended to allow for doors to slide sideways. This was meant to be used in Doom II's secret levels which are based on Wolfenstein 3D levels. The code was commented out when id decided to scale down the amount of Wolf 3d assets in the WAD file. Therefore the doors in the secret levels still open just like those found throughout the rest of the game (unlike the original Wolfenstein 3D doors that opened sideways).
Since Doom and Doom 2 practically use the same executable, any Doom 2 content is technically "dummied out" in the original doom (with the original Doom mode forcefully disabling Doom II specific content in custom maps.) The lack of such protection caused problems in betas v1.5 and v1.6, where the super shotgun could be obtained by an all weapons cheat but either crashed the game or prevented you from selecting the regular shotgun.
Earn Your Happy Ending: After destroying Mars, venturing home to Earth to find that it's been taken over, saving the entirety of the human race, then venturing to hell and BLOWING HELL UP Doomguy deserves this whole-heartedly.
Embedded Precursor: The Limited Collector's Edition of Doom 3 and Resurrection of Evil on the original Xbox includes the original Doom and Doom II. The latter also includes the Master Levels of Doom II. The BFG Edition also includes the first two Doom games.
Enemy Rising Behind: It was possible in Doom although the enemies were generally easier to defend against, but were uncommon. In Doom 3, monster closets are more numerous, and make less noise, making them much more frustrating to some players.
Enemy Summoner: Pain Elementals and the Icon of Sin in Doom II; Archviles in Doom 3.
Energy Ball: Plasma Gun, BFG and some enemies (Hell Knights, mostly) fire them.
Epic Fail: What did the UAC want to do? Make teleporters. Result? Hell invades Earth.
However, in Doom 3, once the UAC higher ups learn about the direction Betruger is taking the project in, they send Campbell and Swann to investigate and — if necessary — pull the plug on the project.
Equipment-Based Progression: In the classic games, the player gets stronger as they find better and powerful weapons, and finding your first ammo backpack permanently gives you double the ammo capacity. In Doom 64, your Unmaker has Artifacts that makes it a much more powerful weapon.
Everything Fades: In the first two Doom games the bodies of enemies stick around forever. In Doom 3, demons disappear in a fizzly animation. This was probably to lighten the load on the game's engine and RAM usage by cutting down on rendered objects. Some mods do undo this and the bodies of humans and zombies generally remain, unless damaged to the point they disintegrate.
Evil Laugh: Dr. Betruger gives several of those in a demonic manner. They range from cool to goofy to downright scary.
Arch-viles give several of those also, when hunting you down.
Evil Versus Evil: You can set up scenarios like this quite easily, and some demon types, such as Cacodemons and Barons of Hell, actively despise each other.
Evolving Weapon: The Unmaker in Doom 64. When you first get it, it fires only a single laser and isn't anything special. If you manage to collect all three Demon Artifacts hidden throughout the game, though, it shoots multiple lasers in a spread pattern and is even more powerful than the BFG 9000 (to the point that only about a half-dozen shots are needed to kill the Final Boss.
Exactly What It Says on the Tin: Betruger. This requires being German or knowing a bit of the language, mind, but it's funny in either case. Translates into something like "deceiver", "cheater" or "swindler.
Doom II: Hell on Earth
Excuse Plot: Demons have invaded Phobos/Earth/Mars! Go kill them all in an over the top and gory fashion.
Expansion Pack: Final Doom contained two of them in one stand-alone game.
Ultimate Doom was a re-release of Doom featuring an additional episode.
Resurrection of Evil is a straight, simple expansion pack for Doom 3.
Except for the Xbox version, which was sold as a complete game due to being a console release.
Exploding Barrels: Doom II has a level full of them — Barrels O' Fun — a classic example.
Doom 3 has a variant on these with the yellow toxic barrels. Once you shoot them, they simmer for a couple seconds before exploding (though they will explode automatically if caught in the splash of another explosive).
Face-Heel Turn: Sergeant Kelly though whether it was before the game began or at some point during it is not made clear.
Dr. Malcolm Betruger could be a another example too. In a log, it's said he once had been a normal human being but after he went into the portal to Hell and came back, he "changed".
Fake Difficulty: A lot of the difficulty in Doom 3 comes from the fact that it's very dark, and the flashlight is the only way to see what you're doing. You cannot use the flashlight and a weapon at the same time. The "Duct Tape" mod and BFG Edition drops the difficulty by an order of magnitude merely by letting you tape the flashlight to your smaller guns and mounted on your shoulder, respectively; it turns out it's a lot easier to play a game when you're allowed to see where and what you're shooting.
The SNES port removed the ability to circle-strafe, making bigger enemies much harder to quickly defeat.
Fan Remake: Doom 64 EX, a successor to the Doom 64: Absolution total conversion, is a fan-made recreation of the Nintendo 64 game for PC with new added features.
The PlayStation version of Doom has a total conversion on PC (requiring GZDoom) with some enhancements and side mods to recreate the feel of the original game.
Fate Worse than Death: What happens to the souls that power the Artifact? It is Hell's weapon after all, so odds are that it isn't pleasant.
Fire and Brimstone Hell: When you do see it. Doom 3's Hell is this, mixed with pulsating flesh and rivers of blood.
In the original game Hell was mainly made of flesh, marble, wood, and stone, with the occasional river of blood and the wall of skinned faces. There are, however, exceptions, such as Mt. Erebus, which featured a charred mountain and floors of glowing, ashen rock streaked with lava.
Game-Breaking Bug: The PlayStation version has a TEXTURE CACHE OVERFLOW bug that crashes the game due to overloading the system's memory (especially on first-generation PlayStations) when a very large number of enemies are present.
Batman Doom: Besides sounding awesome, it was a great technical breakthrough in the early Doom days.
Some mods actually make it to the mainstream media because of the Rule of Fun:
A mod made at the height of the 2010 World Cup, gives the Doomguy a most fearsome weapon: a vuvuzela. The expression on his face is what sells it.
It's not the first of its kind. One previous mod added in a stereo. Sounds pathetic? Well, not even demons can withstand a Rick Roll, apparently.
True Capitalist Doom (Based off of True Capitalist Radio) replaces the protagonist with Ghost, shotguns with "crushing cans", the BFG with a Hadoken, The CyberDemon to play the "FU Texas" song, and so forth. Ghost himself said he liked the mod.
Version 6 also adds six of the player classes from Team Fortress 2, the Postal Dude, of all people, and even the Infected were brought into the fray, along with a Portal Run mode, and Monster Mayhem, which has you dealing with enemies spawning in every-so-often in addition to those already in the maps.
Brutal Doom is Exactly What It Says on the Tin — your weapons have all received a power upgrade (and your wimpy peashooter has been replaced with an assault rifle that can fire on full automatic and is capable of scoring headshots on enemies), the action is much Bloodier and Gorier than the original game with many enemies now capable of being smeared all over the vicinity, the Berserk Pack now gives you the option of doing Fatalities on enemies, and your enemies have received an upgrade as well and are fully capable of ripping you to shreds, making gameplay a lot tougher than the original.
REELism is a not-at-all-serious score-centric round-based survival mod in which an RNG slot machine activates at the beginning of each round to change up the game, altering special effects (such as flight, exploding enemies, or other gameplay-related stuff), weapon spawns (or lack thereof) and enemy types. Things tend to get very frantic, and that's before the boss that appears in the sixth round; as a time-waster that can be played in short bursts, it's a lot of fun.
Gameplay and Story Segregation: The Mother Demon in Doom 64 has the power to resurrect fallen demons, making them stronger than before. You fight it at the end of the game after wiping out a small army of demons, and it never tries to revive any of them.
Gatling Good: The Chaingun. It's been a series staple and can mow down most enemies in seconds. The only time it becomes ineffective is against bosses (except for Vagary and Sabaoth AKA the mutated Sergeant Kelly in Doom 3).
Giant Mook: Revenant, Mancubus, Hell Nobles, Arch Vile, and in Doom 3: Resurrection of Evil, Bruiser.
Glass Cannon: Lost Souls, which die quickly for high-level enemies but can quickly eat away a good 20% or so health if they land a hit.
Cherubs do an incredible amount of damage for their size. Also Pinkies, that are pretty weak and don't do much damage per hit, but attack nonstop, and fast, if close enough. Combined with the Interface Screw, they can bite away with impunity.
In Doom II, the Chaingunners and Revenants are this, the former only having marginally more health than former humans, but able to really put the hurt on you and even other monsters, while Revenants have relatively little health (2 Super Shotgun blasts will kill one) but shoot homing rockets at you, and pummel you to pulp up close.
Guide Dang It: Some of the secret areas can reach this level. The Containment Area in Episode 2, for example, not only has a secret room within a secret room, but there's a secret passage within that secret room leading to another part of the stage, and there's another secret room within that secret passage.
Guilt-Based Gaming: When the player attempts to exit, a humorous quit message is shown, mockingly trying to convince the player to stay and play some more.
Harder Than Hard: The aptly-named "Nightmare!" difficulty, the only setting where monsters you've killed will respawn several seconds after they die. The monsters also shoot more rapidly than on all the other difficulty levels. And cheat codes are disabled. The only good thing about it is that ammo pickups contain double the normal levels of ammo... and you will need it all.
"Nightmare!" difficulty wasn't even included in the earliest releases of the game. It's very hard in single player mode, but it's fine for co-op multiplayer games, which let the players respawn, too.
Heart Container: Health and armor bonuses respectively can raise your health and armor past 100 though you cap at 200. Soulspheres gives you an extra 100 health and Mega Armors gives you 200 armor instantly.
Heroic Mime: The Doomguy (with the exception of the Comic) doesn't seem to have a whole lot to say. This may be because there is nobody to talk to.
Homage: Doom II also had two secret levels lifted almost directly from Wolfenstein 3D, the second of which ended with an appearance by a quartet of (soon-to-be) dead Commander Keens.
Ret Canon: The Doomguy in the cellphone-only Doom RPG series is related to B.J.
Hyperspace Arsenal: Where the hell is the Doomguy keeping all of those weapons? Not to mention the ammo; at the start of the game the player can hold 50 full-sized rockets, in addition to other ammunition and weapons. When you later find a backpack, you double your ammo carrying capacity. A hundred explosive warheads are rather impossible to fit inside a military grade backpack, and that is not accounting for your twenty kilos of bullets and five full boxes of buckshot.
Hyperspace Is a Scary Place: Teleporting in Doom 3 will result in you seeing a terrifying blood-tunnel filled with screams. And occasionally Hell.
In Doom 64 (all difficulty levels correspond to the number of enemies):
Bring It On!
I Own Doom!
Watch Me Die!
In Doom 3:
Recruit: damage taken reduced to 60%, less enemies;
Marine: normal damage taken, normal enemy rate;
Veteran: damage taken increased to 170%; slightly higher enemy rate;
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.
Incendiary Exponent: The Lost Soul. According to the Doom II manual: "Dumb. Tough. Flies. On fire. 'Nuff said."
Indecisive Medium: The film adaptation has a suspicious amount of scenes shot in "first person".
Infinite Flashlight: The only upside of the torch in Doom 3 is that it'll never run out of juice.
Insurmountable Waist High Fence: Central to much of the level design of the first two games, which did not feature any kind of jumping. Later source ports added jumping, allowing players to skip huge swaths of the classic levels by simply hopping over these obstacles.
Taken to the extreme in Ballistyx from TNT: Evilution — the exit linedef is on a chest-height altar that's supposed to be lowered into the ground near the end of the level, meaning you can finish a normally six minute or so map in under two seconds by simply jumping up onto it. Dead Simple in Doom II likewise has the exit switch on a waist-high platform, allowing you to finish it in three seconds just by jumping.
Interquel: The Ultimate Doom, which was published after Doom II, contained a fourth episode for the original Doom, which occurred before the events of Doom II.
Jump Scare: The third game places ample amounts of these in each level, so much that about 20 minutes into the game, you would already became wiser to stay on your guards whenever entering a seemingly empty hallway/room.
Kaizo Trap: Halls of the Damned has a fake exit switch that instead dumps you into a room with a Cacodemon and a ton of Marines.
King Mook: The Spider Mastermind to the Arachnotrons in the original games. Vagary to the Trites in Doom 3; a Queen Mook, if you will.
Large Ham: Betruger. So very much. He starts off overacting, and gets more and more over the top and Narm-tastic as the game goes on - apparently Hell turns you into the offspring of William Shatner. He's SUPPOSED to be scary, and does have a few cool evil laughs, but it's mostly I'LL SWALLOW YOUR SOUL type stuff he yells at you from the great beyond.
Laughably Evil: The demons in Doom 3 are, in an easter egg, this, believe it or not. In a hidden PDA, the demons try to instruct their fellows in how to invade:
"Virgin blood is best." "Goat blood must be no older than 3 days." "Entrails must be removed and apportioned either before death, or no later than 30 min." "Candles must be sorted by tallest in back to shortest in front - never the other way around!" "Most important - pentagrams must be drawn from the center to the outside and left to right."
Level-Map Display: You can always look at a map of what you've explored so far. If you find a computer map, you can see the entire level.
Except in E1M8. Here the computer map is given to you right from the beginning. The level is named "Phobos Anomaly", but the map does not show the anomaly itself...
Life Drain: A variant with the Soul Cube. When it's flung, it kills the demon and transfers all of its remaining life energy to you. Goes well with the lack of medkits late in the game.
Like a Badass out of Hell: Literally. In the first game, he goes from Phobos, to Deimos, to Hell, and then back. In the sequel, he more or less destroys hell. And in Doom 64, he finally decides to stay in Hell to make sure the demons don't try to invade Earth ever again.
Logic Bomb: In early versions of the classic games, monsters can fight each other if they hit each other. But if they somehow hit themselves (typically via barrels, as detailed in this article), they will tear themselves apart.
Doom II introduced Hell Knights, which are a Palette Swap of the Baron of Hell from Doom. They do just as much damage, but have significantly less health. The downside? They appear in numbers larger than Barons would have.
Inverted in The Lost Mission, where the first enemies you face have noticeably less health than normal. Given that the campaign drops you straight into the action against mid-level demons while armed with nothing but a pistol, it's explained by game design.
Ludicrous Gibs: Dealing enough damage will make certain monsters burst into red splatters.
The Soul Cube tends to do this to monsters.
Mad Scientist: Dr. Malcolm Betruger, to literally diabolic levels.
Magikarp Power: The Unmaker in Doom 64 goes through this. When you first pick it up, it only fires a single laser at a slow rate. Finding the first Artifact makes it shoot faster, the second gives it a Spread Shot effect, and the third further ups the effect, effectively reaching beam spamming levels.
Marathon Level: Going by the "par time" at the end of the levels, E2M4 and M6 are 6 and 4 minutes respectively, while it usually never goes to 3 minutes, and Doom II has 7 minutes in Maps 17 and 28. Most maps on Episode 3: Inferno are really long and convoluted as well.
Meaningful Name: The name of Dr. Betruger in Doom 3 means something along the lines of "scammer" in German. They probably intended it to be more like "traitor", but that would be "Verräter."
The third episode of Doom (Inferno!) draws its name and its episode names from The Divine Comedy. The fourth episode (Thy Flesh Consumed), and its levels except the secret level (Fear), draw their names from Bible quotations.
Meat Moss: In Doom 3, some areas are covered with, for lack of a better word, flesh masses that look like turds. If you shoot them, they sound like steel.
And of course, the original Doom series had plenty of fleshy walls and floors once you started descending into Hell.
Medieval Stasis / Schizo Tech: A very strange example in Doom 3. It's 2145, humanity has an established base on Mars, has mastered plasma technology, and is foraying into the science behind atomic structure (the MFS Compactor comes to mind) and teleportation... yet:
The most commonly found storage medium is a square-foot disk with capacity for only a few minutes of video and/or audio.
Security forces lack any kind of enhanced vision, being forced to rely on hand-held flashlights (armor-mounted in BFG Edition) with apparently incandescent bulbsnote granted, the static transfer power supply is an advancement, but still.
All projectile-based weapons seem to use black powder given just how much smoke they produce per shot.
All UAC workers must use a standard issue PDA that is clunkier and less versatile than most of the cheapest tablets you can find in 2012.
Mega Corp.: Union Aerospace Corporation, and in Doom 3, Martian Buddy. Interestingly, despite the mention that the UAC can operate outside of legal and moral obligations, the common "corrupt" aspect of this trope is pretty much averted through Doom 3. The trouble was caused by a lone Mad Scientist who was often at ends with the Corporation's board of directors, who are smart enough to realize that uncontrollable demons running loose are not a good source of revenue, unlike a certain other corporation.
Mission Pack Sequel: Doom II to its forerunner. Same engine, only a single new weapon (the double-barreled "Super Shotgun"), and a handful of new enemy types (one of which is just a slightly weaker palette swap so it can be spawned more often than its stronger brother). However, Tropes Are Not Bad because Doom was a great game and a slew of new maps is not unwelcome. That being said, some of the level design choices in the back half of Doom II don't exactly hold up as well as you'd hope...
In turn, Final Doom is this to Doom II — both were originally full 32-map mods for Doom II before they were picked up to be published by id.
Monster Closet: The Trope Codifier, along with Teleporting Keycard Squad. Often times rooms would be just a pedestal with an item on them, but taking the item opens up all the walls to reveal nasties. If you see a key or very good item, expect the baddies to pop out as soon as you get it.
They did it with Doom 3, where it stretched believability to the breaking point. "They're breaking through the walls!" (radio transmission)
Mook Maker: the final boss of Doom II spews out various enemies, which can telefrag you if you're not careful. And then there's the Pain Elementals, who chuck Lost Souls at you.
The Archviles in Doom 3 are this too, not limited by the number of corpses. Mostly because of Everything Fades.
The fact that Columbine shooter Eric Harris was revealed to play it certainly didn't help matters (not only that, but he made a Doom WAD of his own called UAC Labs, which made it onto DoomWorld's Top 10 Infamous WADs list).
Multi-Mook Melee: Many of the custom "slaughter maps" and Nintendo Hard megawads are mostly made up of these, with some fights in the infamous Deus Vult map (maps 1-4 are parts of the main map, which is map05) or the ever fun "Go 2 It", which involves a brawl against several Arachnotrons and Cyberdemons. The infamous nuts.wad has so many enemies note 10617, to be exact that on badly coded ports framerate slows down to a crawl, even if using a computer made 20 years after the original game. However, serious maps with that many monsters have also been made.
For an idea of how much HP that actually is for those enemies, Cyberdemons only have 4,000. (and spider mastermind only having 3,000. This IS low enough for a point blank BFG-9000 blast to kill it in one shot, BTW.)
No Fair Cheating: Using "-turbo" prints a chat message from time to time. In the original, and most ports of it, cheat codes are disabled entirely in Nightmare difficulty.
No OSHA Compliance: Toxic ooze is easily accessible throughout many levels, though some of it is explained in-game by information suggesting this was due to neglect and the happenings of Dr. Betruger.
The strategy guide for Doom II practically calls this trope out by name: (in regard to the Radiation Suit) "OSHA may not like it, but to get the job done, you're going to have to handle some toxic waste every now and then."
An in-game audio log in Doom 3 features an "accident" report of a worker who, in a trance, stepped back into a particle beam that removed the back of his head. The new "safety" measures that the log author mentions implementing involve a locked cabinet. They do not involve barricading off the particle beam so that no one can accidentally wander into it.
Novelization: Four books based off Doom and Doom II. And two more based off Doom 3.
Doom 3 also counts for using a completely different engine, being the only truly 3D installment in the series (not counting spinoffs.) In addition, its slowed-down gameplay and increased horror elements separate it from every game besides Doom 64, another oddball for using these elements too (though it uses the Doom engine.)
One-Hit Kill: All NPCs in Doom 3 will die in one hit. Even a punch into an unscathed NPC's toe.
Only Six Faces: Doom 3 only has a handful of faces for the various human NPCs, which are re-used frequently. This is most noticeable in the opening Scenic Tour Level, where you can find two guys with the exact same head standing in the same room.
One-Man Army: This may be the current benchmark. Did we mention that he BLOWS UP HELL BY HIMSELF?!
The Only One: You play the lone space marine who was left on guard duty at the ship, now the only thing standing against the hordes of hell.
Overdrawn at the Blood Bank: Doom was one of the few video games in the early 90s that demonstrates that 2D sprites can spill lots of blood shot and killed, and some enemies can be gibbed when killed by high-powered weapons.
Password Save: In the PlayStation and Saturn versions of Doom and in Doom 64, although Doom 64 also supports a save function whereas the PlayStation and Saturn versions does not.
In Resurrection of Evil you're able to use the Grabber to snatch an enemy's fireball out of the air and hurl it back at it.
The BFG-9000, no matter the incarnation. In Doom 3, they travel so slow that you can literally shoot them out of the air before they hit you!This is, in fact, how you're supposed to defeat Sabaoth.
Not just limited to the monsters, Doomguy's Plasma Gun in Doom 3 has this defect. Supposedly it balances out how the Plasma Gun has a zero-degree spread when sustaining fire, but it makes the Plasma Gun horribly inefficient when fighting enemies like Lost Souls, Cacodaemons, and to a lesser extent Cherubs.
Phlegmings: The Hell Knights from Doom 3 have this when they roar.
Physical Hell: Doom's entire plot revolves around the idea that teleportation experiments on Mars resulted in portals to Hell itself, cue The Marine. Also, the Martians in Doom 3 already did the same thing by accident long ago, sacrificed most of their civilisation to fix it, and fled to Earth.
Psychotic Smirk: The marine is rather passionate about battling Hell's hordes as, after a new weapon is picked up, the protagonist grins devilishly at prospect of blowing away demonic forces with it.
The best part is when he makes the grin while his face is covered in blood.
Punny Name: Several songs on the soundtrack, including but not limited to Kitchen Ace (And Taking Names) and Nobody Told Me About Id.
Bye Bye American Pie was both a play on the song name "American Pie" and one of the level designers of Doom II, American McGee.
Quad Damage: The Berserk Pack multiplies fist damage by ten times. For the rest of the level. You can gib weak mooks by punching them.
There's a (hopefully) intentionally crappy mod out there called All Hell is Breaking Loose! Among such things as flying demons that shout "Fuck you!" and flip you off when they die, the zombie soldier gib animation is replaced with them burning to death. This means that you can set someone on fire with a punch.
Also the second power of the Artifact from ROE is a berserk charge that lets you one-shot any enemy in the game (except bosses) with your fists. Considering the FIRST power is Bullet Time and the THIRD power is invincibility it's obvious why the Artifact is a major league Game Breaker.
Reassigned to Antarctica: The Doomguy in the original two games assaulted a superior officer who ordered him to fire on civilians. Rather than a court martial that would make them look like monsters if the reason for it got out, they decided to assign him to Mars — a barren rock whose only notable features were scientific outposts on its moons, and which was never expected to see any sort of action.
In Doom 64, not only is Hell's sky red, but in some levels it's on fire.
Reformulated Game: Doom 64. The redone levels and enemies, darker graphics and horror-inspired soundtrack gave the game a much different ambiance than the original game, even if the gameplay is for the most part still the same.
Regenerating Health: Inverted in Doom 3's Nightmare difficulty, where your health constantly decreases by five points every five seconds until it hits 25.
Right-Handed Left-Handed Guns: Completely averted in the original Doom games, where the Doomguy is very notably shown to be left handed; both in the way he holds his guns, and when he's using his fists.
Road Runner PC: The Doom marine was intentionally faster than normal monster movement, and could be made faster with a command line option. What wasn't intentional was strafe-running (+40% speed boost), and wall hugging (massive speed boost).
Rocket Jump: Ur Example in first-person shooters. There's no vertical lift, but it does toss you around. One secret was specifically designed to require a rocketjump... though it can be reached just by straferunning.
Scenic Tour Level: In Doom 3. Unlike most examples, they give you a gun and even allow you to murder your co-workers even before things go to hell.
Schizophrenic Difficulty: Episode 4 of Ultimate Doom suffers from this. The level progression goes like this: starts out really hard -> ungodly difficult -> not as hard -> pretty easy -> about medium -> really difficult again -> somewhat easy -> ends on a rather medium difficulty level.
Schmuck Bait: In Doom 3 BFG Edition's Lost Mission, there's a room where a revenant blasts out the windows, forcing you to run through a few Imps to hit a button and close the emergency shutters. Unlike the control panels in most other similar situations, this one stays functional after you've fixed the problem. No prizes for guessing what happens if you hit it again...
The first several levels of Doom II are pretty standard difficulty. Things really ratchet up once you hit "Dead Simple" and "Tricks and Traps", with large groups of high-tier enemies appear very frequently.
Final Doom (The Plutonia Experiment and TNT: Evilution) takes Doom II and ratchets it Up to Eleven.
Like many expansion packs, Resurrection of Evil is noticeably more difficulty than the original Doom 3, with large groups of high-level demons regularly appearing to attack you, and the introduction of an insanely powerful Giant Mook (the Bruiser) who's equipped with dual full-auto rocket launchers that can gib you in seconds. This is balanced out by the new Artifact, which grants you superpowers for a limited period of time.
Set a Mook to Kill a Mook: A vital survival technique, especially in levels with more monsters than you can shake a boomstick at. If an enemy damages another enemy, they will engage each other.
The first area of E3M1 didn't have enough ammunition to kill all the Beef Gates. It was punch them to death, or get them fighting each other. Since Imps and Cacodemons both had ranged attacks, getting them to hit each other was relatively easy. Then the retaliation started...
E2M9, the secret level in the second episode, had two rooms. One with Barons of Hell, the other with Cacodemons. Again, the trick was to get them fighting each other, then maneuver for survival. (Lampshaded in the novels.)
Map 8 of Doom II has a room with a Cyberdemon and several Barons of Hell facing away from you. The trick? Cause infighting to dispose of one group, then take down what's left. No wonder it's called Tricks And Traps.
Map 20 of Doom II contained a large antechamber with a Cyberdemon and a Spider Mastermind on two opposite platforms. No prizes for guessing the easiest way to waste them both. The level is appropriately named 'Gotcha!'
This sequence exists mostly to try and answer the Ultimate Showdown of Ultimate Destiny-style question of who would win. (It's usually the Cyberdemon, but the Spider Mastermind's odds improve in inverse proportion to the distance between them. Gotcha! is just on the Cyberdemon's side, although Spidey does sometimes win. In some rare cases, they can end up killing each other.)
Lost Souls behave differently with in-fighting. They will make at most one attack when damaged (but can still exchange blows), and resume attacks on the player.
Shareware: One of the most well known examples, Doom is probably the one title above all others which destroyed forever the "shareware is shareware because it's nowhere near good enough to sell at retail" myth. It was the first shareware product ever to be reviewed in the main pages of British PC Format magazine, instead of being relegated to the shareware section.
Doom II did not receive a shareware release, on the other hand. This was because, according to John Carmack, many people who downloaded the shareware episode Doom and beat it mistakenly considered themselves to have "beaten Doom" when they beat the demo.
Also because shareware was essentially a distribution method: download the (longer than average) demo, and if you like it, mail order the full version. Doom II was conceived as a retail product from the start, so all of that was unnecessary. And then Id decided to rerelease Doom at retail, as well...
Carmack has said in a 20th-anniversary interview that shareware was actually not such a great fit for Doom. Not because any problem with the strategy itself, but because the game was such an obvious generational leap forward in game technology at the time, it literally sold itself, without need of any marketing gimmicks.
Shoot the Medic First: The Archvile in Doom II can revive fallen foes, so killing this guy first is essential. However, he can also deal out a ton of damage with his line-of-sight attack. In ZDoom, it is possible to create enemies that can resurrect fallen foes via Decorate. Again, death for these guys should be top priority.
First, after defeating the Barons of Hell in the final level of the first episode, the only way out is through the teleporter... which takes you to the lost Deimos base, where you're immediately overwhelmed by monsters and die (the coding in that room ends the level once you reach 11 HP or lower). Specifically, you die and go to Hell, but since Deimos was mysteriously teleported to Hell, nothing really happens. The debriefing text really drives it home: "Once you beat the big badasses and clean out the moon base, you're supposed to win, aren't you? Aren't you? Where's your fat reward and ticket home? What the Hell is this? It's not supposed to end this way!"
And of course, the end of episode three. The Space Marine escapes from Hell and returns to Earth... only to find that the demons he had been fighting have already invaded. Cue the the sequel.
Short Range Shotgun: While the original pump-action shotgun was somewhat realistic, the double-barreled shotgun from Doom II was probably the Trope Maker, as it hit with the force of a bazooka but was was hopelessly inaccurate at further than arm's reach. Doom 3's only shotgun followed suit. Of course, considering how 2/3rds of the game are basically corridors, you'll spend a good amount of time within 2 meters of your enemy, which is why this gun is still the most practical gun to use in the game.
On the source port side, ZDoom has the developer's console cheat "anubis". Typing it in and pressing enter results in every monster in the game fleeing at the sight of you. Why? Because the message displayed when you hit enter is QUAKE WITH FEAR. Typing "anubis" again and hitting enter deactivates the fear effect with the message "No more Ogre Armor".
Also, the ancient Martian panel showing off the last Martian using the Soul Cube is actually a recreation of the cover art above. Parts of the mural are broken off (notably heads), though.
In the film, Dwayne Johnson actually had to fight to keep the "BFG" reference. There's also Pinky (who gets chainsawed), a Hellknight, and Reaper saying "Hell on Earth".
Doom 3 had Nabcom retro arcade consoles scattered about the early levels. This included one console you could actually play, Turbo Turkey Puncher, a Game Within a Game based on graphics from the original Doom games.
None of the weapons in classic Doom except the pistol and the shotguns have sights, eithernote the Rocket Launcher's worldview sprite has a rear sight if you look really close, but the player character fires it from the hip anyway.
Speedrun: These games developed one of the earliest online speedrunning fanbases.
Splash Damage: The always venerable rocket launcher, along with the classic Exploding Barrels. BFG, the biggest gun in the game, does not deal blast damage in the traditional sense, though; it instead fires a cone of invisible beams (from the player, not the projectile) when the main projectile hits anything.
Spider Tank: The Spider Mastermind(s) and the Arachnotrons.
Standard FPS Guns: Fists, Chainsaw, Pistol, Shotgun, Chaingun, Rocket Launcher, Plasma Rifle, BFG. Doom was very important in creating/popularizing this one.
Stock Sound Effects: Pretty much everything, from the monster roars to the launch sound of the monster spawn cubes in MAP30 (all three of the officially-published Maps 30), thanks to id licensing sound FX from the Sound Ideas library. This is why all, or nearly all, of the FX used in Doom sound familiar to movie buffs; they've been used in many movies and TV shows, both before Doom and since. In fact, one of the stock sounds is known today as Doom Doors.
The Stoic: The marine from Doom 3. Never shows any form of emotion on his face, even fear, just frowns when new sorts of monsters appear. The only time he shows fear is when he meets the Cyberdemon.
Strange Secret Entrance: Some of hidden levels in the series are like this. For example, getting to one secret level required you to blow yourself off a ledge by firing your rocket launcher into a wall at point blank range.
Stupid Evil: Dr. Malcolm Betruger, who apparently has no actual motive for attempting to transform Earth into Hell and its people into screaming demon-fodder. It is implied, however, that he has been possessed or is in some way controlled by the demons. The novels indicate he was an ordinary scientist who was subject to More Than Mind Control, alternatively The Lost Mission campaign indicates he always had an obsession with the occult and was offered ultimate power by the demons in exchange for Earth.
Super Title 64 Advance: Doom 64. It was originally supposed to be called The Absolution, but got its name changed to follow along with the naming convention of other 64 titles. Unfortunately, this led to people mistaking it for yet another port of the original game, when in fact it is a unique game.
The PlayStation port of Doom has the subtitle "Custom PlayStation Edition".
Surprisingly Sudden Death: The first time you see a Lost Soul in Doom 3, it rips itself away from within a female scientist's head.
Symbol Swearing: Doomguy's reaction upon finding the Unmaker in Doom 64: "What the !@#%* is this!"
Tank Controls: The default setting for the PlayStation and Saturn versions of Doom and Doom 64. You can change the controls in the PlayStation and Saturn versions although the customization is not as extensive as Doom 64.
Tele-Frag: Just like "frag", it was also first coined in Doom multiplayer matches. Some Doom levels allow you to telefrag monsters (e.g., E4M2 in Ultimate Doom). Doom II's final boss can also telefrag you if its monster-spawning projectile makes its impact right where you're standing. note "Last Call" (MAP30 of TNT: Evilution) has a second Player 1 start in a sealed-off area — and most of the islands in the lake between the start and the main part of the level have teleport linedefs which take you to this area, so if you don't take exactly the right route across the lake, you telefrag yourself.
If you're playing Doom 3's co-op mod, telefrags are possible (yes, STILL) at the beginning of the level if your teammate spawns on top of you. Seen here, as Grah kersplats Draikk simply by materializing.
Telefrags also ignore whether the telefragged is invulnerable or not and just outright splats them. To be exact, "invulnerable" (whether by Power-Up or by God Mode cheat) means "immune to attacks scoring 1000 Hit Points or less of damage", but a telefrag does 10,000 HP damage.
Doom 3 has a PDA Audio entry detailing a lab monkey being split in half. Literally. The upper half went there and the lower half stayed behind.
Teleporting Keycard Squad: More often than not, you can expect to find a horde of demons swarming upon you when you pick up a keycard.
There Is No Kill Like Overkill: The "Russian Overkill" mod adds dozens of ludicrously-overpowered weapons (and some that are not quite so overpowered but are either funny, clever, or just plain bizarre) that effectively remove any challenge the game ever had. At least one weapon's alternate-fire mode can one-shot a Cyberdemon. To say that some of these guns can wipe out an entire level's monster population with a single round is, in many cases, barely an exaggeration.
Title Drop: In Doom 3, Councillor Swann states that if the demons get control of the ships, everyone on Earth is "Doomed". In The Lost Mission from the BFG Edition, the load screens for Hell and Hell Outpost include a pair of quotes from the bible about the coming "Day of Doom".
Doom 64 has a sort-of example, with the final map being named after the original title for the game: The Absolution.
Trope Codifier: For the FPS genre. For years, all FPS games were known as "Doom clones".
The rude, manly space marine has become ubiquitous since then.
The "crate maze", as first seen in E2M2: Containment Area, has also become an FPS cliché. It originated as a good way to have a large area without overtaxing the engine.
Unique Enemy: In Doom 3, in the second level you encounter a "fast zombie" in the infirmary. It can run almost as fast as you can, and would have made a pretty challenging enemy if encountered in large numbers. The one you see in the infirmary is the only one in the entire game, with all other zombies being the standard "slow shambling" type.
Fridge Brilliance kicks in when you realize said zombie...isn't actually a zombie, but rather an insane man that went to town on his body with a scalpel and had been, until the moment all hell broke loose, kept heavily sedated (As noted in the Doctor's audio log).
E2M4: In version 1.1, approaching the yellow key, retreating to a different room, and returning causes the crushing ceiling to be permanently lowered and sometimes blocking access to the key. That version forgot the original ceiling height whenever the crusher stopped.
"Dead Simple" from Doom II: The central stair raises once you kill all Arachnotrons. If played on Nightmare, Arachnotrons can respawn and be killed off again, allowing you to raise the central stairs out of reach.
"Pharaoh", the first secret level from TNT: Evilution, is Unwinnable in single-player mode, but not co-op mode. This is due to the yellow key being marked as "Multiplayer-Only". (But you can still complete it using straferuning, an engine bug.)
You can patch your TNT-iWad with Doom Patcher. It will create an iWad without said bug. However, it won't fix the node-building error which is also present, so you will still be unable to get 100% kills. It's far better to use the official TeamTNT PWAD to fix both these bugs.
"Even Simpler" from Doom 64 is basically a remake of "Dead Simple," only with Pain Elementals thrown in. You have to kill every enemy, including the Lost Souls they shoot out, to advance. If they're killed next to some walls, however, the Souls they are supposed to shoot out get sucked into the walls, making it impossible to kill them.
In Doom 3 a number of doors are supposed to lock behind you once you walk through them. However, it's possible to walk through one of these doors and then back out before they close (usually because an enemy jumped out at you), and end up on the wrong side of the door when it locks, causing you to be unable to proceed furthur.
Unwitting Pawn: The marine from Doom 3 will become this if he send the signal from Mars to Earth for reinforcement, playing right in to Dr Betruger's hands. If not, Betruger will send it himself.
Updated Re-release: After 8 years, Doom 3 was re-released as Doom 3: BFG Edition. It's primarily geared towards bringing the game to consoles (the only previous console release was for the original Xbox, and had noticeably decreased graphics to run on the system), but is available for purchase on the PC as well. The updated release includes improved lighting and rendering (although not as modernized, say, the fan-made Sikkmod mod), support for 3D TV display, and (only on the PC version) support for the Oculus Rift VR headset. It also has console-oriented features such as achievements and save checkpoints. A new set of levels called "The Lost Missions" are part of the game as well. The entire game has been tweaked to be more action-oriented and closer to the feel of the original games, in contrast to the slower-paced, more survival horror-like presentation Doom 3 originally had. This includes faster player speed, less ammo hunting, slightly redesigned levels, etc.
Ultimate Doom added no new monsters or weapons (not even the new ones added in Doom II), really just a new episode, to the original game. It was basically an excuse to get Doom (formerly distributed as shareware) sold in retail stores.
The Xbox LIVE Arcade version of Ultimate Doom and Doom II has updated graphics and music, and online multiplayer.
Compilation Re-release: The BFG Edition includes Doom and Doom II, albeit the Xbox LIVE Arcade ports that have various alterations including the censored versions of the Wolfenstein 3D secret levels in Doom II... on the plus side, it gives PC gamers a chance to officially play the Doom II XBLA-exclusive episode "No Rest For the Living". In November 2012, the PlayStation 3 received another compilation called Doom Classic Complete, which includes the original two games plus "No Rest for the Living", as well as Master Levels for Doom II and Final Doom.
Doom: Collector's Edition for PC includes Ultimate Doom, Doom II, and Final Doom on a single disc. It also allows players to play the classic Doom games without using virtual machines such as DOSBox or source ports.
The id Anthology not only compiles of all the classic Doom games, it also includes Wolfenstein 3D, Quake, and the entire Commander Keen series across four CD-ROMs. This collection also added some bug fixes to TNT: Evilution and The Plutonia Experiment.
Video Game Cruelty Potential: All of the survivors you meet in Doom 3 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. In fact, this is actually a smart thing to do, as many of the civilians in the intro sequence become zombies. One of the cruelest is activating a machine that will strip or melt the flesh off a scientist's bones, complete with a few seconds of horror and terror as the scientist realizes what is about to happen to him. In the BFG Edition, this one gets you an achievement.
Villain-Beating Artifact: The original version of Doom 3 requires that the player use the Soul Cube to take care of the final boss Cyberdemon. This was changed both in later patches of single-player mode and in co-op mode.
The Unmaker and Demon Artifacts in Doom 64 are a partial example. Neither are required to beat the Mother Demon, but each of the artifacts shuts down one of the enemy spawn points in the final level, as well as powering up the Unmaker until it's the most powerful weapon in the game.
The Walls Have Eyes: Some wall sprites have moving walls of faces staring at you, and in later episodes/levels of Doom the switches are now stone heads whose eyes glow when you hit them on. Other switches are are just eyes protruding out of fleshy patches, closing when activated.
The War Sequence: Custom levels pitting the player against massive hordes of enemies (called "slaughter maps") are somewhat popular amongst the Doom community, the official Doom levels have a couple of their own as well, the most infamous being Go 2 It from Final Doom, which is a remixed version of the first stage from Doom II with over 200 enemies, including 19 Arch-Viles and 13 Cyberdemons (fortunately, you don't have to fight them all at the same time; unfortunately, you do have to fight up to 4 at a time.)
Weird Moon: Most of the first game occurs on Phobos and Deimos, which are the Martian moons. They are both represented as sort of small planets / big moons with an atmosphere. The actual Phobos and Deimos are just tiny bare rocks and the whole areas of Episode 1 (Phobos) and Episode 2 (Deimos) of the game are each bigger than the moons themselves.
Entire sections of Doom 1 and 2 would either take place in dim light, or flickering Blackout Basement-styled areas.
Fortunately, keen players were able to see in all but the darkest of areas without the light-amp goggles on DOOM's default rendering. (The engine rendered everything below a certain light level as pure black.) However, playing the games on Zandronum's OpenGL option causes these areas to become near pitch black. There's still the savior of the automap.
Doom 64 likes to throw in dark levels as well, the Dark Citadel being the most egregious example.
You Have Failed Me: Surprisingly averted for once. While it seems that Betruger suffers this fate by the end of Doom 3, the Expansion PackResurrection of Evil revealed that not only did the demons gave him a safe sanctuary in Hell so that he wouldn't suffer from human retaliations, despite his plans failing, but they also gave him a new, stronger and aerial-able demonic body and supernatural powers as well a commanding rank in the demonic hierarchy.
You Keep Using That Word: Doom started the FPS trend of misusing the word "chaingun" to refer to rotary guns; a chaingun is actually a single-barrel weapon which operates its bolt with an electrically-driven chain.