Doom cheat codes
To use a cheat code in most versions of the game, one simply types the code while playing (this also applies while in automap mode). On the iPhone version of the game, touch the screen with 4 fingers at any time to bring up the keyboard. After the last letter has been entered, a message of acknowledgment will appear at the top of the screen. The status bar, face, and ingame view may also change, depending on the effects of the code.
Cheat codes are disabled on the "Nightmare!" skill level, except for the iddt and idclev cheats.
 All Doom engine versions
|idbehold#||When # is one of the letters below, this gives the powers of an item:|
|idchoppers1||Gives the option to select the chainsaw.|
|idclip||No clipping in Doom II (see idspispopd below for technical details).|
|idclev##2||Warps to level E#M# or MAP##. This may have certain side effects (see IDCLEV idiosyncrasies).|
|iddqd3||Sets health to 100% and makes player immune to damage ("god mode", "degreelessness"). If the player is currently standing on or subsequently enters a damaging floor of type 11, the invulnerability effect is nullified. The invulnerable player can also be killed by a telefrag, and projectiles with extremely high damage ratings (such as from a DeHackEd modification, or standing on the landing spot of a spawn cube when it lands) can also kill a player in god mode.4|
|iddt5||This cheat reveals information if used while in automap mode, showing additional data the second time it is used:|
|idfa6||This is the same as idkfa below, but excludes the keys.|
|idkfa7||Grants full megaarmor protection (200%), all weapons, full ammo, and all the keys.|
|idmus##8||Plays music from level MAP## in Doom II or Doom, and E#M# in The Ultimate Doom. Using this cheat code will make the player change weapons in hand if the numbers pressed correspond to available weapons.|
|idmypos9||Shows the player's coordinates and compass direction (note that these numbers are hexadecimal, and may require some practice to interpret quickly).|
|idspispopd10||No clipping (the player can walk through walls, monsters, and obstacles, climb high ledges instantly, and pass through items and across all tagged linedefs with no effect. This works only in Doom and The Ultimate Doom (see above for the equivalent idclip for Doom II).|
1. ^ Prints the message "Doesn't suck - GM". Taylor's explanation for this message: "Choppers is a State Programming Contest game that a friend of mine named Guy Maor (GM) helped write. He's a little defensive of it 'cause it wasn't *quite* finished on the release day. Was a cool two-player Rescue Raiders rip-off. He was drunk and talked to me one night, and I thought I'd put it in."
2. ^ CLEV stands for 'change level'; it could also be interpereted as "see (C) level."
3. ^ Taylor and two fellow hackers made up an informal fraternity called Delta-Q-Delta (hence the DQD) during their college days. The "Q" stands for "quit", and represents the grade members should strive to receive in their classes.
4. ^ According to the function P_DamageMobj in p_inter.c, "invulnerability" only protects the player from attacks doing less than 1000 points of damage. There is no form of attack in the game that does more damage than this number, except one: a telefrag, which inflicts 10000 points on the target. This is why a player in God mode can still be killed by telefragging. This also means that DeHackEd can be used to circumvent god mode by creating incredibly powerful weapons; some examples of this effect can be found in The Sky May Be.
7. ^ KFA stands for 'kick fucking ass', killer fucking arsenal or 'keys & full ammo'.
8. ^ MUS stands for 'music'. Certain selections may call for invalid music lumps (see IDMUS requests invalid music). In The Ultimate Doom, idmus40 will play the same music as idmus39 (D_E3M9) and idmus41 to idmus45 will play music from the intermission, main, and end screens. In Doom II, the non-level tracks are idmus33 to idmus35.
9. ^ MYPOS stands for 'my position'.
The prefix FH in Doom95 cheat codes stands for the initials of Fred Hommel, the programmer who created the codes.
|fhhall1||Kills all monsters in the level, excepting lost souls. (Pain elementals killed in this manner will still generate extra lost souls as normal).|
|fhshh2||Monsters do not notice players unless they are hurt or hear a shot.|
- HALL refers to Jason Hall, CEO of Monolith, who requested that particular cheat (hence the "BY REQUEST..." message that displays when the code is executed). The actual damage done to each monster is 10,000 hit points.
- Upon typing the fhshh cheat the message "be vewy vewy quiet..." is displayed. This is a reference to Elmer Fudd's catchphrase "Be vewy vewy quiet, I'm hunting wabbits!", in the beginning of a Looney Tunes or Merrie Melodies animated short. The message "Achoo!" appears when the cheat is disabled (the joke being you sneezed, and the monsters heard you).
 See also
- Cheat codes
- Source port cheat codes
- PlayStation Doom cheats
- Player face grins after restoring savefile
- ClassicDOOM.com's cheats guide
- The etymology of Doom cheat codes, from Lee Killough's archive
- alt.games.doom post about creating weapons that can kill invulnerable players, via Google Groups
- rec.games.computer.doom.editing post about creating weapons that can kill invulnerable players, via Google Groups