Enter the codes below when "Press Start" appears at the opening screen. For all the codes, you will hear a sound after you have entered the code.

Freeze Thrower/Unlimited Ammo:
Down, Up, A, L, R, Z

Shotgun/Unlimited Ammo:
Up, Down, Left, Right, L, R

Action Mode:
Down, Down, A, Z, Z, Left, A

1st Person View
Down, Up, L, B, Z, Left, C-Up, C-Right, C-Left, Z

Unlock MultiPlayer Characters(GROUP 1):
A, L, R, Left, B, Down, Up

Unlock MultiPlayer Characters(GROUP 2):
B, A, A, R, L

Unlock MultiPlayer Characters(GROUP 3):
L, L, Up, Down, R, B, A

Unlock MultiPlayer Characters(GROUP 4):
B, B, R, Left, A

Unlock MultiPlayer Characters(GROUP 5):
Right, B, Left, L, A, Z

Unlock MultiPlayer Characters(GROUP 6):
Up, Down, B, A, A, Left