Press TALK (default is T) during game play. The game will freeze, but has not crashed. Enter one of the following codes, then press ENTER to activate the corresponding cheat:

CHEAT FUNCTION - CHEAT CODE
Invulnerability - god
Full armor - armor
Full health - health
Full ammunition - ammo
Ghost mode - poltergeist
Spawn indicated weapon - gimmegun
All weapons - guns
All guns with unlimited ammo - tears
More Health, Reflex and 10 Med Packs - gear
Position mode - pos
Build mode - build