Greed Demo Cheat Codes
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KMFDM       Backpack of Holding (full ammo)
OMNI        Omniscience (reveal map)
CHANNEL7    Rob Lays Eggs (?)
ALLAHMODE   Godmode on/off
BELFAST     Deathkiss (kill all enemies)
RAVEN       Ambrosia (full shield and health)
BEAVIS      Get objective items. Only 100 points left to complete level.
GULLIVER    Midget Mode on/off
BLAMMOx     Get weapon x (1-6)

(Quoted from a post by Theo Savidis)