At the main console (hit Backspace), type in:

AMMO            full ammo
ARMOR           200 % armor
CHOJIN          become immortal
FREEZE          (debug) freeze all monsters.
FULLMAP         view the full map
INVISIBLE       2 minutes of invisibility
KILL            kill every thing immediately
REANIMATE       (debug) reanimate all monsters.

Chant Jeranian and William Ball