ORIGIN: UK Pocketeer no. 31374

VARIANTS: Space Invasion

GAMEPLAY: As arcade video games became popular around the late 70s, several Pocketeers attempted to ape elements of their play - this is, obviously, a take on Space Invaders. You pull a lever to wind up the timer, then the set of three barriers in the middle moves from side to side while you attempt to shoot through the gaps and hit the alien saucer to score points.

VARIANT: Space Invasion

ORIGIN: US Tomy Pocket Game

DIFFERENCES: Name and graphics. The US version has been designed to more closely resemble arcade Space Invaders, with the laser base, bunkers and five rows of aliens all looking very much like their coin-op counterparts.