Zeke is a skeleton
Hold [A] + [B] + [X] + [Y] at the
opening sequence, before the legal screen. Release the buttons
at the title screen.
Zeke is invisible
Hold [A] + [X] + [L] + [R] at the
opening sequence, before the legal screen. Release the buttons
at the title screen.
Weapon upgrade
Hold [Right], then press [X]x2, [Y]x2,
[B]x3, [A] during game play.
Full health
When low on health, save then quit the game. Reload
the saved game to resume with your health restored.