Landers, Mutants, Baiters and Swarmers all sound dreadfully familiar and it didn't need much guesswork to decide that Guardian was going to be another version of Williams' classic space shoot-out, Defender.
A deadly swarm of Baiters and assorted nasties follow your spacecraft as you skim the planet's surface in a desperate bid to protect the last colony of humanoids from the fearsome Landers.
Swooping in at great speed, you first a burst, destroy the Lander and rescue the failing humanoid. Once safely back to earth, the patrol continues in a swift and often hair-raising flight across the planet. Should the Landers succeed in capturing the Humanoids, they in turn will mutate into something nasty and pursue your fighter in deadly earnest.
Further planets await you with an increasing number of humanoids to rescue as the game progresses. With its fast action and smooth scrolling screen, Guardian is one of the best games I've seen on the Electron.
The game sticks faithfully to Williams' original and is comparable to Acornsoft's Planetoids.
The keyboard controls are simple and easy to master - essential in a game where speed and accuracy are of vital importance to your survival.