I found whipe-out 64 by far the hardest raceing game I've ever played.
also honorable mention has to go to the prince of persia games. not the new ones. but the OLD 2D scrollers... that shit was hard as hell
and mother fucking Kid Fucking Icarus for gameboy brick. I got to like level 2. then I just got no further. no saveing, beat it or start over... thanks nintendo. Pits a bitch