1. Amnesia: Dark Descent. Quite possibly the most immersive gaming experience ever, can't play the game by myself way too good at getting under my skin.
2. Condemned : Criminal Origins (just the first one, the sequel was a pile of garbage, wasn't scary in the slightest where the first had me constantly looking over my in game characters shoulder for baddies.)
3 Silent hill series
4.Penumbra series (from the same makers of amnesia, this was their first series of games which like amnesia are incredibly immersive)
5.dead space, (was initially pants wetting but later became run of the mill shooting galore, although I am eagerly waiting the sequel)
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I am so omniscient, if there were to be two omniscience's I would be both! Prepare yourselves for the subjugation! - Ziltoid The Omniscient.