Jeff Minter‘s original 1982 VIC-20 version of Gridrunner is not a bad game overall. It’s a simple Centipede variant fought on a basic grid background, with sprites zipping all over the place and insects trying to get the better of you by destroying you before you can destroy them.
Two X and Y lasers fire their beams occasionally as you try to shoot segments of the centipede itself, which worms its way down the screen from left to right. Shooting the insect’s body creates yellow spores that require even more shots to remove, but the ultimate aim is to take out the entire centipede before you lose all your lives.
Gridrunner is basic stuff now, but at the time it was revolutionary. In 1982 there wasn’t a great deal of commercial software around and Llamasoft stepped in to provide some. For VIC-20 owners, Llamasoft games were highly-regarded and often widely played, and Gridrunner was no exception.
More: Gridrunner on Wikipedia