In game press Ctrl+Alt+~ and to type:

God = God Mode
give all = All weapons, full ammo, health and armor
noclip = Walk through solid objects
notarget = Invisibility to most enemies
kill = suicide
killmonsters = Kills all Monsters
give ammo = Max Ammo
give health = Max Health
give keys = All keys

就是說從重返德軍總部,DOOM3,到現在的QUAKE4所用的作弊碼都是一樣的