Recommend some good horror games

It's almost Halloween season. I'm a big horror fan and was hoping to gather some recommendations from the community, possibly use this thread as a hotspot for other users to check out some scary titles. I'm for sure going to delve in Amnesia. Can you guys recommend anything else?

I'd recommend the Dead Space Series (particularly 1) and Alan Wake.

Also if you're giving Amnesia a go Penumbra is from the same developers and I believe it was their first game.

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