I can't really think of anything except PS1 games right now. Crash Team Racing, Donald Duck: Quack Attack, Strikers 1945 II and Digimon Rumble Arena come to mind. Then there are some of those older, very linear games that really don't allow much percentages. Either you beat them or you don't.
I wish I could say Medievil but my friend finished it for me. Same happened with The Dukes of Hazzard: Racing for Home. Weird thing with that one, the title does say what I just wrote but the disc says Sherif Fais-Moi Peur, Maybe that could be a DYKG
I would totally have fully finished Vigilante V8 if my disc wasn't so screwy. It wouldn't allow me to unlock UFO so I never truly beat it.