You've seen it all before. The space invaders tramp predictably across the screen, edging relentlessly earthwards. You wipe them out mercilessly with your quick firing laser base, rapidly clearing the first screen. It appears all too easy - then all hell breaks loose...

The second wave doesn't follow a set pattern. They swarm about all over the place setting up defensive boxes. If you don't break them up they will be your downfall. Moving quickly earthwards they have landed before you can gather your shattered wits. And that's only the second wave - there are nine in all, each progressively worse.

POSITRON is a fast moving, colourful and satisfying game. So sharpen your wits, tighten your sweatband and give it a whirl.