On the screen right after the title screen, the one with the animation, type “LETS LOOK AT WHAT YOU COULD HAVE WON”. Then type “SUPER SMASHING GREAT”. Now press ‘P’ to unpause the game and press the joystick button to start the game. This will give you infinite energy and will enable the following keys:
‘F1-F5’________Skip to corresponding level.
On the same screen type “FRITH MODE”. I’m not sure what this does as of yet.