I was just though a game where it impossible to take damage, or die, or fail, but it still scared me pretty badly to suddenly have a pair of giant eyes stare at me though previously blank windows; probably because I was counting on a little girl to show up and stare at me wordlessly and was watching entirely the wrong region of the screen when the eyes popped in. It didn't hurt that the solution to the puzzle was to hide from the eyes as quickly as possible.
Was that Gateway 2? Yeah, that game creeped me out, mostly just because of the odd atmosphere of it.
I was reaaaallly dissapointed with Dead Space. I'm glad I rented it, it wasn't particularly scary for the most part, but it was an O.K. rental. All hail Gamefly!