I can honestly say it been quite some time since I played a game that sent shivers down my spine. This game is a prime example of what a game in the Horror/Thriller genre should be. The atmosphere is a contant, fearful paranoia, from start to finish, and the survival part of the game just enhances the whole experience.
As mentioned by agentwaff, the lack of a pause button was simply a stroke of pure genius, I think most people do get tempted to press the pause button in these sorts of games due to the "Fear Factor", and it sometimes ruins the experience.
This has well earned it's 5 stars, I'm looking forward to more games from you. :)
(Oh, and advice for people who keep dying on the second day:
On the second night onwards, you might have to put logs in the fireplace during the night, as the fire tends to run out quicker at night. So, make sure have a spare log in your inventory, and keep an eye on the room for darkening areas. Also, make sure it's not your hunger or thirst that's killing you.)