Thought I'd revist this as the Steam Sale is back on for Winter!
A friend just bought me Frozen Synapse and that is a really tense tactical game, very difficult to Master. Quite like playing Infinity.
I'm playing Amnesia: A Machine For Pigs and though I am enjoying it, I despair at the game design choices in it. None of the amazing diary entries are narrated - there's no sense of exploration and the puzzle solving so far is... slender.
I got Slender: The Arrival for cheap on an indie bundle and I'm sorry to say it still feels like a freebie Unity game. Still a nice, scary experience but I need to play more to get an opinion on it.
Twisted Shadow Planet: Got this with Slender in the deal - it's like a mixture of Loco Roco with a bit of World of Goo in the dark style, but the gameplay is like a simplified Metroid so far. Something that might play better as a zone out game on the TV.
Outlast: Amazing that such a small studio made this horror game - again, a bit frustrating but a lot to recommend.