Flaming Shotgun
Pause game, then enter: T,O,O,S.
Level Jump
At the password screen, enter: GOLVL, then a level number (like, GOLVL20).
Levels go to 34, 35 is then ending.
Cheat, EVERYTHING!
(all weapons, levels, invincibility and unlimited ammo) At the password screen, enter:
1gotp1nk8c1dbootson
Note: 1 = the #1, not an I
Cheat
TYPE IN 1GOTPINK8CIDBOOTSON FOR THE UTIMATE CHEAT.