Connect a gun to port one, and a standard controller to port 2. Press [Up], [Down], [Up], [Down], [A], [X], [B], [Y], [C], [Z] at the title screen. A gun shot will confirm correct code entry. Big head, free play, and gun select options will appear in the option plus menu. (The option plus menu appears after the game has been completed under any difficulty level.) The big head option normally appears after fifty eight cumulative games are played.
Gun select/unlimited ammunition
Enable the "Cheat mode" code and the gun select option under the option plus menu. During game play, pause and shoot off-screen to cycle through the weapons. Use this method to select the special auto-fire weapon with unlimited ammunition
Options Plus mode
Additional options, such as mirror mode and bookkeeping, will appear on the options screen after the game is completed.
Hold one of the following buttons on a control pad at the stage selection screen until game play begins:
Rage: Hold [X]
Smarty: Hold [Y]
Janet: Hold [Z]