The object of the game is to prevent as many of the alien worms as possible from reaching the ground. You have two weapons. A laser lance which has unlimited range, uses your energy sparingly and can kill one worm at a time only. The dragon's breath which has a limited range, uses a lot of your energy but can kill several worms at a time. You can replenish your energy by feeding on the magenta coloured firestones. The dragon's skin colour changes to reflect it's energy level.