Can humans play Simon Birrell games? If you thought Bug Bomb was fast, Microbe is manic. The story goes that you've been blasted into an all-powerful alien's bloodstream to eliminate its biological defences - antibodies, aminos, ribosomes, red cells and spores - from the inside. Biology 'O' level is no advantage.

You pack a gun in each of your crab-like claws and can not only move back and forth along the bottom of the screen, space-invader fashion, but can go up and meet the nasties head on. It's a cross between Galaxians and Centipede, but there are no hiding places. Really, it's a very slick and professionally designed game. The sound and visual effects are exemplary - but oh it's fast!