The Doom Bible is the original design document for Doom, written by Tom Hall in 1992. Much of the content seen in the document is not featured in the final version of the game. There have, however, been some obscure attempts by fans to make a custom WAD based on the content seen in the document. Many of those attempts have, seemingly, been abandoned.
Some bits and pieces from the Doom Bible show up in various places:
- The prefixes TROO and SARG on IWAD lumps for the Imp and Demon come from their Doom Bible names: Demon Trooper and Demon Sergeant.
- The game Doom was originally going to be named "Attack Of The Attackers" but they decided that was too silly and changed it.
- The Unmaker, a weapon described in the Doom Bible as being made entirely of demon bones, would later appear in Doom 64.
- The Knife, Bayonet, Machine Gun, and Dark Claw were all considered for release after Tom Hall's leave, but were cut due to time constraints and balance.
- Of all the proposed episode names, only Knee-Deep in the Dead made it into the final game. It was originally to be the third episode of six.
- The game originally took place on a planet called Tei Tenga. Some of the Doom computer panel textures still contain the text "UAC BASE TEI TENGA". The 1995 3D Realms game Terminal Velocity  also featured a planet called Tei Tenga.
- All of the playable characters in Rise of the Triad, a contemporary of Doom, had origins in the Doom Bible. Some had their names altered, and one only appeared as a possible name, but one or two were unchanged from their original descriptions.
- The four characters that were featured in the doom bible as playable, were all supposed to be similar in appearance in-game, presumably to save time on development. The only really big difference would be the color of their outfits.
- The Doom Bible proposes the idea of a severed hand that the player must use to open a door. In Strife, there is a level where the player must use a severed hand to unlock several doors. Similarly, in the movie, Sarge uses a severed hand to unlock the BFG room. Both of these may be coincidences, however. 1997's Quake II had a similar moment where the player uses the Captain's Head to unlock a door. At the QuakeCon 2014 Doom 4 (re-titled simply "Doom") gameplay unveiling, it is alleged by attendees that, at one point, the player ripped off an arm of a dead soldier and used it on a biometric scanning device to access a previously locked area.
- In the Doom movie, the BFG 9000 is named "BFG 3.14"; The original description of BFG can be found in section 14 of the document. (This likewise can be a coincidence,as PI also shares the same number.)
- The demon troops were described in the bible as very damaging at close range. The document also stated that later troops would be able to cast magic of some kind. In the final game, these demon troops are Imps, and they are able to throw fireballs from the beginning, and they are, as the document says, damaging at close range.
- The first episode according to the bible is Evil: Unleashed, which is also the name of the Jaguar Port for DOOM.
- One of the prominent features of the Doom Bible is the story. The exact opposite is true for the final release of Doom. It is rumored that John Carmack felt that the emphasis on story slowed down the game more than it helped it.
- Some of the features in the document are quite similar to some featured in Doom 3, such as personal lockers and a blood receptacle, possibly similar to the health station in Doom 3.
- The document features talk of a game (possibly) based on the film Aliens, released in 1986.
- You can find some of the locations that are mentioned in the Doom Bible in Alpha 0.4. Things such as chairs, a rifle sprite not seen in the final release, and a bayonet sprite and animation. There is also several marine models seen in a "lounge"-like area. These are more than likely the marines featured in the Doom Bible.