Here are some cheats and tips for the game Zombie Revenge.
Cheat mode:
Accumulate points in the VMU mini-game to unlock the “Eternal Life”,
“Area Select”, “Free Continue”, and “Free Time Limit” cheat options
in original mode.
Alternate costume:
Highlight a character, then hold Start and press B, X, or Y.
Hidden items in Biological Weapon Plant level:
Note the fan at the beginning of the Biological Weapon (Industrial
Sewage) Plant level. Shoot it (you can not use a button) to collect
some hidden items.