Gridrunner's action takes place on a yellow grid, representing Earth's latest solar power generator, now overrun by aliens. Your mission is to clear the grid with the aid of a super-blaster.

A klaxon-like warning sounds as the screen alerts you: "Battle Stations. Enter grid sector 01." There are in fact 31 sectors you can choose to enter. Your small green blaster appears on tlre grid and moves freely with the aid of a joystick around the lower portion of the playfield.

Gridsearch squads which resemble wriggly worms come: down very quickly and break into smaller worms when hit. They leave behind pods, which change shape and eventually explode, sending bombs hurtling down.

The XY Zapper also plants pods, and sends a lethal beam vertically up to catch you unawares. All these creatures can be killed by blasting away with your high speed cannon.

Gridrunner is rather like an abstract version of Centipede, with 'spacey' sound effects. Detailed instructions make comprehension and playing fairly easy, but the game moves so fast that it takes a little getting used to.

Not all that original but for dedicated arcade players a fast and enjoyable game with good sound and graphics.

D.A.