ORIGIN: UK Pocketeer no. 31334 (1976)

VARIANTS: Copter Fight (Coleco Pocketfuls), Bi-Plane Battle (Tomy Pocket Game)

GAMEPLAY: Odd shooting game - you're shooting at a bunch of enemy gangsters in their car, but every hit you score nudges them closer to their hideout, so that your "reward" for a perfect game is having your enemies escape to safety. Which isn't very motivational, if you ask me.

VARIANT: Copter Fight

ORIGIN: Coleco Pocketfuls

DIFFERENCES: Name, colour, theme and graphics. Makes slightly more sense this way, since you're shooting the enemy copter in order to make it blow up, not to help it get away.

VARIANT: Bi-Plane Battle

ORIGIN: US Tomy Pocket Game

DIFFERENCES: Name, colour, theme and graphics.