Just wanted to say that we just released our horror game "Amnesia: The Dark Descent" yesterday. I have mentioned it in a few post and while not a 100% notgame project, a lot of notgame thinking has gone into it. There is no "fun" gameplay at the core really, there is very little trial and error we have had a holistic / top-down approach where we started with a feeling and then let everything added support that. There are gamey elements in the game and I know Michael disliked a few parts with enemies

The plan was to add an easy mode (with no dangerous enemies) but we did not have time. Perhaps we will add it for a patch.
In any case, I think that the notgames thinking has served us very well. What we have tried to do is to put some more responsibility on the player and require them to roleplay in order to be engaged in the game. This has been very visible in comments, as some players are simply unable to do this (perhaps to used to cheap action based thrills that do not require anything?), but quite a lot of people have, seemingly unconsciously, been able to immerse them self. Horror is probably by far the easiest emotion to do this for, but I think it bodes well for the future and I hope to explore it more.
I liked this reddit write up:
http://www.reddit.com/r/gaming/comments/db2d4/my_amnesia_the_dark_descent_experience_last_night/it shows how the player managed to almost create the experience by themselves.
And we also got a, extremely surprisingly, positive review from Game Informer
Amnesia is barely a game in the traditional sense, leaving the nearly two decades of horror gaming tradition since Alone in the Dark by the wayside and forging its own twisted path.
http://gameinformer.com/games/amnesia_the_dark_descent/b/pc/archive/2010/09/08/horror-done-right.aspx Here is a link if you are interested:
http://www.amnesiagame.com