Arcade: Defender, Robotron 2112, Asteroids, and for good sound Gyron.
C64: Bolderdash, Matrix, Hover Bover.
Spectrum: JetPac.
PC: Captain Keen, Fractint.

Megadrive: Flashback (apart from the door which does not open).
PS123: FIFA '06 (maybe better versions, but this one got well played).
I could add to these, but I think it better to point out some good games with minor faults.
C64: Elite (nice but when auto dock was selected there was no way to avoid an hour long t-break), Valhalla (Could always summon Odin (maybe thrice) and get him to do all the work).
Spectrum: Ant Attack (very complicated keys to learn in a dinner hour

).
Cheers Jacko
Pi=B256R0USB CL4SD8GB Raspbian Stock. 13D https://dl.dropbox.com/u/1615413/Own%20Work/Dimensions.pdf ... Looking for an interesting project to hold my attention.