Haunted Mansion

Cheat List
During game play, hold RIGHT, then press the following button
combinations:

Invincibility: B, X, X, X, B, X, Y, A.

Level Select: X, X, B, Y, Y, B, X, A.

Upgrade Weapon: B, B, Y, Y, X, X, X, A. -

Hidden Area
Find the bat statue in the great hall and hit "B".
Go back to the fire place and walk down into it.

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 + B + L + R at the opening sequence, before the legal screen.
Release the buttons at the title screen.

Health Restoration
Save and quit your game. Then load back your saved game, and you'll
begin at the save point with maximum health.