What was the scariest video game you ever played?

I've always been pretty big on the entire Resident Evil and Silent Hill series... Both scared me until I learned where the shotguns are, then I would just clear rooms out one by one. Silent Hill (especially in the first three) had the radio, so it was a bit tense entering a room knowing there's something messed up in there with you, but you can't see the damn thing before it comes running at you.

Resident Evil was really only scary whenever I encounter invincible enemies like the T-102 and Nemesis. All you can do is run and hope the camera doesn't mess you up, lest you get smacked around or tentacle raped haha.