Fat Worm is locked inside a Spectrum's architecture, and is looking for a disk drive, in order to produce a clone of himself, which he presumably will Write Once and Read Many. He moves around the arrangement of chips, processors and boards, with the aim of finding his way through. On the way he will encounter bugs (of the insectoid type) which must be shot at, by 'blowing a sparkie' - releasing a bolt of electrical energy. Mines and impact shots can both be fired. Contact with these bugs causes them to jump on you, gradually slowing your movement and sappoing your energy. You must collect spindles in order to get rid of them.