One game that hasn't been mentioned, that I remember playing a lot on the Apple ]['s that our school had was "Rocky's Boots". Looking back, circuitry diagrams and logic gates were a bit advanced for 9 year old me, but I remember really enjoying it.

Surprisingly, they recreated that in Linux in the xScreensaver package.

Can't say I've beaten them all, some I've only played for a few hours at most, but still.