Press ~ after starting the game, at the screen
where the items are described. Proceed for two more screens and
press [Backspace] at the screen with the magic lamp to
enable cheat mode. Then, press one of the following keys during
game play to activate the corresponding cheat function.

Key
Level select 1A through 1M
Level skip [Keypad plus]
Five apples A
Five gems G
Toggle invincibility H
Toggle free movement M
Toggle objects in some levels U