Fire and reload the lightgun or controller at a blank portion of the main menu to spell out the code words. The number of times Fire is pressed corresponds to a letter in the alphabet, with 1 being the equivalent of "A" through 26 being the equivalent of "Z". Press Reload to move on to the next letter.
Master code
Enter "MEBIGCHEAT" as a code. Press Fire(13), Reload, Fire(5), Reload, Fire(2), Reload, Fire(9), Reload, Fire(7), Reload, Fire(3), Reload, Fire(8), Reload, Fire(5), Reload, Fire, Reload, Fire(20), Reload at the main menu. If you entered the code correctly, the screen will flash.
Arcade mode
Enter "BLAM" as a code. Press Fire(2), Reload, Fire(12), Reload, Fire, Reload, Fire(13), Reload at the main menu. If you entered the code correctly, the screen will flash. The "Arcade Mode" option will now be unlocked in the extras menu. If you entered the code correctly, the screen will flash. Alternately, successfully complete the game.
Country challenges
Enter "ABROAD" as a code. Press Fire, Reload, Fire(2), Reload, Fire(18), Reload, Fire(15), Reload, Fire, Reload, Fire(4), Reload at the main menu. If you entered the code correctly, the screen will flash.
Mighty Joe Jupiter mini-games
Enter "MIGHTIER" as a code. Press Fire(13), Reload, Fire(9), Reload, Fire(7), Reload, Fire(8), Reload, Fire(20), Reload, Fire(9), Reload, Fire(5), Reload, Fire(18), Reload at the main menu. If you entered the code correctly, the screen will flash. Alternately, successfully complete all Mighty levels in cadet training mode to unlock the "Mighty Joe Jupiter Trilogy" option in Mighty Joe Jupiter mode. Complete the easy levels in cadet training mode to unlock Mighty Joe Jupiter Episode 2. Complete the normal levels in cadet training mode to unlock Mighty Joe Jupiter Episode 3.
Jukebox and music test
Enter "LETSBOOGIE" as a code. Press Fire(12), Reload, Fire(5), Reload, Fire(20), Reload, Fire(19), Reload, Fire(15), Reload, Fire(15), Reload, Fire(7), Reload, Fire(9), Reload at the main menu. If you entered the code correctly, the screen will flash. Alternately, successfully complete all episodes in the Mighty Joe Jupiter Trilogy to unlock the "Music Jukebox" option at the Options screen.
Ending bonuses
Successfully complete the game to unlock the "Arcade Mode" option at the extra menu and the "Mirror Mode" option at the arcade mode menu.
Machine gun
Successfully complete the game in arcade mode using the pistol. Start a new game in arcade mode to use the machine gun.
Cane gun
Successfully complete the game in arcade mode using the machine gun. Start a new game in arcade mode to use the cane gun.
Shotgun
Successfully complete the game in arcade mode using the cane gun. Start a new game in arcade mode to use the shotgun.
Hyper Arcade mode
Successfully complete the game in arcade mode using the shotgun to unlock the "Hyper Arcade Mode" option at the arcade mode menu.
Endgame (PS2)
