Shotgun with infinite ammunition When "Press Start" appears at the opening screen, press Up, Down, Left, Right, L, R. If the code was entered in correctly, you will hear a sound. Rifle with infinite ammunition When "Press Start" appears at the opening screen, press C-Up, C-Down, C-Left, C-Right, L, R. If the code was entered in correctly, you will hear a sound. Freeze Thrower with infinite ammunition When "Press Start" appears at the opening screen, press Down, Up, A, L, R, Z. If the code was entered in correctly, you will hear a sound. Group 1 multi-player characters When "Press Start" appears at the opening screen, press A, L, R, Left, B, Down, Up to unlock all Group 1 multi-player characters. If the code was entered in correctly, you will hear a sound. Group 2 multi-player characters When "Press Start" appears at the opening screen, press B, A(2), R, L to unlock all Group 2 multi-player characters. If the code was entered in correctly, you will hear a sound. Group 3 multi-player characters When "Press Start" appears at the opening screen, press L(2), Up, Down, R, B, A to unlock all Group 3 multi-player characters. If the code was entered in correctly, you will hear a sound. Group 4 multi-player characters When "Press Start" appears at the opening screen, press B(3), R, Left, A to unlock all Group 4 multi-player characters. If the code was entered in correctly, you will hear a sound. Group 5 multi-player characters When "Press Start" appears at the opening screen, press Right, B, Left, L, A, Z to unlock all Group 5 multi-player characters. If the code was entered in correctly, you will hear a sound. Group 6 multi-player characters When "Press Start" appears at the opening screen, press Up, Down, B, A(2), Left to unlock all Group 6 multi-player characters. If the code was entered in correctly, you will hear a sound. Skin select When "Press Start" appears at the opening screen, press C-Left, R, Left, Up, Down, B, A, Z. If the code was entered in correctly, you will hear a sound. Skins may be selected in single player mode, but may not be viewed during selection. First person view When "Press Start" appears at the opening screen, press Down, Up, L, B, Z, Left, C-Up, C-Right, C-Left, Z. If the code was entered in correctly, you will hear a sound. Action Nuk'em mode When "Press Start" appears at the opening screen, press Down(2), A, Z(2), Left, A. If the code was entered in correctly, you will hear a sound. Alternatively, successfully complete the game to unlock Action Nuk'em mode, which allows Duke to kill opponents with one shot. Extreme mode Beat the game with all babes rescued and all opponents killed to unlock Extreme mode, which allows the game to be played at a higher difficulty setting. Bonus multi-player characters Beat any level and save the game to unlock one additional character in multi-player mode. Big head mode Rescue all babes in level 2, "Liberty Or Death", to unlock the cheat option for big head mode. Big gun mode Kill all opponents in level 3, "Nuclear Winter", to unlock the cheat option for big gun mode. Flat shade map Obtain all secrets in the "Wetworld" secret level to unlock the cheat option for flat shade map. Ice skin Rescue all babes in level 5, "Fallout", to unlock the cheat option for ice skin. Weather Obtain all secrets in level 6, "Under Siege", to unlock the cheat option for weather.