At the Title screen left click the top left corner of the gray border and without moving the mouse type Type CTHULU (v1.2) or YOG (v1.3). If done correctly you will hear a gong sound to confirm and the following commands will be available.
Adds 10 Lives: F10
Fast Game Play: Ctrl + F6
Skips Level (Plays Cut Scene): Ctrl + F8
Skips Level (Cut Scene Ignored): F12
Skips 5 Levels (Cut Scenes Ignored): F11
Control Mad Monks: Control the Monk with the T-Y-U/G-H-J/B-N-M Keys, press TAB to switch monks.