At the main menu, choose the "Options" selection. Select the "Cheats" option, the enter one of the following codes to unlock the corresponding option at the "Cheats" menu:

Infinite Health

Enter "beets" as a code.

Infinite Level Skip

Enter "beldam" as a code.

Free Hall Passes

Enter "well" as a code.

Button Eye Coraline

Enter "cheese" as a code.