STRANDS of DNA are firmly connected in most people's minds with biology lessons, yet PSS has succeeded in basing Xavior on those tiny gene carriers.

Xavior, the last surviving member of his race, must find and collect all the strands of DNA which carry the make-up of his people from a subterranean storage complex. Only when that is done can he ensure the perpetuation of his race.

The game starts at the entrance to the cavern; Xavior enters and at once sees a shimmering blue orb in a corner of the room. He picks it up knowing that this will de-energise the doors to each room in the complex. However, the orb has only enough power to neutralise four doors, and though others can be collected en route it is wise to pick them up only when needed.

Your task is enormous - hidden in over four thousand rooms are a small number of DNA strands guarded by apparitions formed from pure energy. You have just enough time to run through each room before they materialise, but should you stop to pick up an orb or piece of DNA then they will do their best to neutralise you.

Xavior is the kind of game which leaves you panting in frustration, convinced that it is impossible to find all the strands of DNA and thus complete the game. The instructions state that the player must find the secrets to the orbs - an impossible task if, indeed, any secrets exist.

However, for those that like bashing their heads against a brick wall - this is the game for you.