Open the console by pressing "~", then type any of the following codes:

Cheat Code - Granted Wish

NEXT LEVEL - Win Current Level and Skip to Next
REB GOD - God Mode
REB INFINITE AMMO - Unlimited Ammo
GIVE [character's name] [item name] - Give Item
GIVE AND EQUIP [character's name] [item name] - Give & Equip Item