I was going to say Space Invaders or Track & Field or Out Run - but for sheer fun and frustration in equal measure:
Pac Man -
I remember my mates and I going to this dodgy video shop off Broad Street station back in the mid-1980s, just because it had games like Missile Command, Tempest, Lunar Commander and so on...
But Pac Man ruled then....
(PS: in case you're a Londoner wondering where Broad Street Stn. is today, it was knocked down years ago to become part of the current Liverpool Street Station complex)