The Haunted Mansion Cheats

Invincibility
While playing, hold Right then press X, B, B, B, X, B, Y, A.

Level Select
While playing, hold Right then press B, B, X, Y, Y, X, B, A.

Weapon Upgrade
While playing, hold Right then press X, X, Y, Y, B, B, B, A.

Skeleton Zeke
Before the copyright screen at start-up, hold A, B, X, Y.

Invisible Zeke
Before the copyright screen at start-up, hold A, X, L, R.