Pause the game by pressing space and type “RAINBOW” three times. Now unpause the game by pressing the fire button. You can then pause the game again by pressing space and use the following in game keys:
‘C’ - Fill the current cauldron
‘S’ - Skip level
‘T’ - Complete the game and view the end sequence
The way the cheat works is rather strange - only one cheat key is enabled each time you type the word “RAINBOW”. The first time you type it enables the ‘C’ cheat, the second time enables ‘S’ aswell and the final time enables ‘T’ to complete the game.