Every Ninja Gaiden since Black
Assassin's Creed II
God of War II
Star Wars Knights of the Old Republic
Whoa, that's seriously impressive.Metroid Prime for sure; if nothing else, it's the game I've played start to finish the most.
I recently got my completion time down under 2 hours (in-game clock), which isn't that fast (considering the WR is something like 53 minutes), but I felt good getting it!
Also recently, I managed a Varia-less Magmoor run which is basically the worst thing to do while learning the advanced movement in that game. It led to this nice screenshot, though!
Baldurs Gate 1 and 2 I have to play them with self imposed ironman no reloading if I die its game over to have any kind of challenge.