You know what I'd really love to see here on TAY? A semi-regular column devoted to classic pre-PC gaming. Apple II and Commodore 64 and Amiga and Atari ST, etc. I played some of my first games on such systems, but not enough to really be able to write about them. Ellen?
Anyway, there's a really great post on Slate about one such game that is so difficult, it took the author and some of the players he interviewed decades to complete it. Robot Odyssey requires some basic programming skills just to get through the first few levels, and was even used as a programming teaching tool long after the 5.25" floppy drives it ran on were no longer available.
I learned to program in BASIC using a similar but far less complex Apple II game, Flowers for Algernon. It had nothing to do with the book from which it took its title, as I recall.
Just to stay on topic, what's the most insanely difficult game you ever tried? QWOP? I Wanna Be the Guy? Super Meat Boy? Hell, I still struggle with Ice Climbers.