Press Pause and then hold L + R and press A, B, A, A, B, B, B, A.

To activate God Mode, pause, then hold L+R, then press A, A, B, A, A, A, A, A.

To get all weapons and items in the game, pause, then hold L+R, then press A, B, B, A, A, A, A, A.

To become invincible, pause the game, then hold L+R. Press B, B, B, A, A, A, A, A to become untouchable.

To unlock Berserk Mode, pause the game, then hold L+R. Press B, A, B, A, A, A, A, A.

To see the computer map, pause the game. Then hold L+R and press B, A, A, A, A, A, A, A.

To get the radiation suit easily, pause the game and hold L+R. Then press B, B, A, A, A, A, A, A.