Bonus characters:
Complete the game with any of the eight regular characters to play as Zetton, Ace-Killer, Alien Magma, and Gomora. One of those four characters will become available each time the game is completed.

Special gallery:
Unlock all four bonus characters. A "Special Gallery" selection will appear under the "Gallery" option with graphics and information about the bonus characters.

Super attack:
Press Triangle + Circle + Square.