Source port cheat codes

Other Ports
To use a cheat code in most versions, one simply types the code while playing (this also applies while in automap mode). After the last letter has been entered, a message of acknowledgement 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. All of the codes for the original game work in all ports, unless otherwise noted.

Cheat codes in vanilla Doom are disabled on the Nightmare! skill level, except for the iddt and idclev cheats. However, many source ports enable cheats for all skill levels.

In some ports and in the original executables, cheat codes may be different on non-QWERTY keyboards. For example, in France, idkfa may be idkfq, because of the AZERTY keyboard layout commonly used there.

Doom 95
The prefix "fh" stands for the initials of Fred Hommel, the Doom 95 author who created the codes.

The "hall" in "fhhall" refers to Jason Hall, CEO of Monolith, who requested that particular cheat (hence the "BY REQUEST..." message that displays when the code is executed).

EDGE
In addition to new cheat codes of its' own, EDGE also allows the user to edit the cheat inputs to their own leisure through the language.ldf file. The codes below are the default forms of the new cheats.

Eternity
As well as supporting the additional Boom/MBF cheats, Eternity adds a number of its own.

ZDoom
In order to use cheat codes in ZDoom, the variable "sv_cheats" must be set to "1" (true). This variable can be set by launching ZDoom, accessing the console via the tilde ( ~ ) key, and typing "sv_cheats 1". One should then be able to use any ZDoom-specific cheat by typing it into the console.