Cheat mode
Fire and reload the lightgun or controller at a blank portion of the main menu (or off the screen totally) to spell out the code words. The number of times Fire needs to be pressed corresponds to a letter in the alphabet, with 1 being the same as "A" through 26 being the equivalent of "Z". Press Reload to move on to the next letter.

Master code
As a code enter "MEBIGCHEAT". Press Fire(13x's), Reload, Fire(5x's), Reload, Fire(2x's), Reload, Fire(9x's), Reload, Fire(7x's), Reload, Fire(3x's), Reload, Fire(8x's), Reload, Fire(5x's), Reload, Fire, Reload, Fire(20x's), Reload while at the main menu. The screen will flash to verify proper entry.

Arcade mode
As a code enter "BLAM". Press Fire(2x's), Reload, Fire(12x's), Reload, Fire, Reload, Fire(13x's), Reload while at the main menu. The screen will flash to verify proper entry the "Arcade Mode" option will now be available in the extras menu. Or just finish the game.

Country challenges
As a code enter "ABROAD". Press Fire, Reload, Fire(2x's), Reload, Fire(18x's), Reload, Fire(15x's), Reload, Fire, Reload, Fire(4x's), Reload while at the main menu.

Mighty Joe Jupiter mini-games
As a code enter "MIGHTIER". Press Fire(13x's), Reload, Fire(9x's), Reload, Fire(7x's), Reload, Fire(8x's), Reload, Fire(20x's), Reload, Fire(9x's), Reload, Fire(5x's), Reload, Fire(18x's), Reload while at the main menu. Or finish every Mighty level in cadet training mode to access the "Mighty Joe Jupiter Trilogy" option in Mighty Joe Jupiter mode. Finish the easy levels in cadet training mode to access Mighty Joe Jupiter Episode 2. Finish the normal levels in cadet training mode to access Mighty Joe Jupiter Episode 3.

Jukebox and music test
As a code enter "LETSBOOGIE". Press Fire(12x's), Reload, Fire(5x's), Reload, Fire(20x's), Reload, Fire(19x's), Reload, Fire(15x's), Reload, Fire(15x's), Reload, Fire(7x's), Reload, Fire(9x's), Reload while at the main menu. Or finish every episodes in the Mighty Joe Jupiter Trilogy to access the "Music Jukebox" option at the Options screen.