Deathmatch cheat mode
Type t in the map to enter talk mode. Hold [Alt] and type iddt several times. This will reveal the entire map. Repeat the code to reveal all items. Repeating the code again will return the map to normal

To enter cheat mode
Enter one of the following codes during game play to activate the corresponding cheat function.

Code Effect
iddqd Invincibility
idkfa All weapons, keys, ammo, and 200% armor
idfa Reset ammunition
idbeholds Berserker strength
idbeholdv Temporary invincibility
idbeholdi Temporary invisibility
idbeholda Full automap
idbeholdr Anti-radiation suit
idbeholdl Light amplification visor
idspispopd Walk through walls
idchoppers Chainsaw
idclev Level select
iddt Toggle full map; full map and objects; normal map
idmypos Display coordinates and heading
idmus Change music to indicated level
fhhall Kill all enemies in level
fhshh Invisible to enemies until attack

Enemies

Former Soldiers: They resemble your old friends, but now they just fire pistols at you. They drop clips for the chaingun and pistol when killed.
Former Sergeants: Meaner and tougher. They carry shotguns and do more damage then soldiers. They drop shotguns when killed.
Imp: This creature throws fireballs and takes more bullets to kill.
Demon: Appear in most areas and can rip your head off if you are not careful. If you see more of them, use the chaingun.
Cacodemon: These creatures are ugly and have one big mouth. If they see you, they will fire lightning balls from their mouth. Use your rockets.
Mancubus: You have to use more then a chaingun to kill them. Use ammo with caution.
Arachnotron: Fires plasma energy at you. Use your rifle.
Spider Demon: The ultimate enemy. Has a super chaingun mounted on her body. Use your plasma rifle or rocket launcher.

Network cheat mode
Hold [Alt] and type iddtiddtiddtiddt in map mode