The Haunted Mansion Codes -

Zeke is a skeleton:
Hold + + A + at the opening sequence, before the legal screen. Release the buttons at the title screen.

Zeke is invisible:
Hold + + + at the opening sequence, before the legal screen. Release the buttons at the title screen.

Invincibility:
Hold , then push , (x3), , , , while playing the game.

Weapon upgrade:
Hold , then push (x2), (x2), (x3), while playing the game.

Level select:
Hold , then push (x2), , (x2), , , while playing the game.