Pause the game and enter: L, L, L, R, R, R, R, R, L, R, R, R, R, L, L, L.

To get an extra life, enter this password: LLRR LRLL LRLL RRLL

To get more ammo, enter this code: LRRR LLRR LLLL RLLR

To move faster, enter this code: LRRR RLRL RRLL RLRR

To take less damage, enter this code: LRRR RLLL RLLL LLLR

To enable higher jumps, enter this code: LLRR RRRR LLRR LLLR

To make your opponents faster, enter this code: LRRR RRLL LLRR RRLL

To make your opponents slower, enter this code: LLRR RLRR RLLR RLLR

To make your enemies stronger, enter this code: LLRR RRLR RRLL LLLL

To reverse the controls, enter this code: LRRR RRRL RLLR RLLL