Unlock ALL Levels and Fast Bikes:
At the Main menu press C-Up, C-Left, C-Left, C-Right, L, R, C-Down, Z.

Unlock ALL Weapons:
At the Main menu press C-Up, C-Up, C-Up, C-Down, L, C-Left, Z.

Unlock ALL Weapons and Quadruple Damage:
At the Main menu press L, L, R, R, L, C-Up, C-Right, Z.

Change to Female:
At the Mmain menu press C-Right, C-Left, Z, L, R, C-Up.

Unlock Level 2:
At the Menu Select screen press R, C-Right, Z, R, L, C-Up, C-Left, C-Up.

Unlock Level 3:
At the Level select screen press R, C-Right(x3), R, C-Left, C-Down, Z.

Unlock Level 4:
At the Menu screen press R, C-Right, C-Down, C-Left, C-Right. C-Right, Z, L.

Unlock Level 5:
At the Menu screen press Z, C-Right, C-Down, C-Left, C-Right, C-Right, Z, L.

Ener the following codes to unlock the corresponding effect. If the code has been entered correctly you will hear a sound as confirmation.

Unlock ALL Weapons and Quadruple Damage:
At the Main menu press L, L, R, R, L, Top C, Right C, Z.

Unlock ALL Weapons:
At the Main menu press Top C, Top C, Top C, Bottom C, L, Left C, Z.

Unlock Level 2:
At the Menu Select screen press R, C-Right, Z, R, L, C-Up, C-Left, C-Up.

Unlock Level 3:
At the Menu Select screen press R, C-Right (x3), R, C-Left, C-Down Z.

Unlock Level 5:
At the Menu Select screen press Z, C-Right, C-Down, C-Left, C-Right, C-Right, Z, L.