Extra weapons: Type baabaa at the weapons option screen to get some extra weapons. Type aabaab to disable this cheat.
Unlimited sheep: Type bobjob at the weapons options screen.
Rapid fire missiles: Type aabaab while shooting a mini-gun.
Extra turn: Type aabaab while firing a banana bomb.
Unlimited bazooka missiles: Select a target with the Uzi, then hold [Shift] and F1 and press [Space].
Description by VGTips