The tension is building for me in Silent Hill. That music and gloomy atmosphere work on you after a while.
I was thinking today about games that scare me. Games like Condemned don't because I can always fight. Games that get to me are ones that go for that psychological influence, either through the music, the atmosphere, or by bombarding you with hysterical characters like in Bioshock. I can't stay in those game worlds for too long or my nerves get rattled.


