Gridrunner

The game is similar to the Atari, Inc. arcade game Centipede, with long, segmented enemies that progress in a zig-zag fashion and can be broken apart. Players control a small ship that can fire upwards and move freely around the screen. The player must also avoid pulses emitted by the X-Y zappers which patrol the edges of the grid. The game has twenty waves of enemies to complete.

Llamasoft released Gridrunner in 1982 for the unexpanded VIC-20. The game was written over the course of a single week. Although it draws its inspiration from the arcade game Centipede with the concept of a snake-like enemy descending the screen through a series of obstacles (mushrooms in Centipede, pods in Gridrunner) it plays much faster. Versions of the game appeared for several of the home computers of the early 1980s.

The name of the game was inspired by posters advertising the film Blade Runner.

In April 1983, the game topped the US computer game sales chart. In 1984, The Commodore 64 Home Companion advised to "forget the plot; fast action is the name of this game".

In 1983, Minter released Matrix: Gridrunner 2, which retained much of the original's gameplay, but introduced new enemy types and a scrolling background. It was first published on the Commodore 64, and ported to other platforms. This title was released in the US as Attack of the Mutant Camels, a title taken from an unrelated Llamasoft title released in the UK. A second sequel, Voidrunner, followed in 1987, which abandons the grid backgrounds, and features more colorful and elaborate graphics.

In 1991, Llamasoft released Super Gridrunner for the Atari ST. The first 32-bit title in the series, it added power-ups to the series for the first time, while retaining the basic elements of a single-screen shooter. This would be the last entry in the series for over a decade, during which time Jeff partnered with Atari on updates to the Tempest and Defender series.