Most difficult games you've ever played?

[Sage84]

How about Terminator 2 on the Sega Mega Drive!!

FCUK ME that was hard! Even with 2 players and cheats I NEVER got past the level where the truck was being chased by Terminators - if you've played it, you'll know exactly which bit I mean!

[Malius]

Commander Keen (with no codes) I was 8 but damn it was hard. Only game I didn't finish. Also Alex Kidd in miracle world but my parents didn't let me keep the master system on overnight.