Terrifying. Perfectly done atmosphere.
This is a peice of art. The atmosphere is emmersive and horrifying. Each move is carefully crafted to scare the hell out of you.
Every time a new element was discovered or introduced into the game, it was done perfectly.
Unlike other games which could overuse things, ruin certain scenes etc - this game has none of that.
The fade in/out between scenes took along time but if that hadn't been present, I feel I would have attempted to rush through the game.
A few technical glitches when I put it to fullscreen such as the background screwing up, but that didn't ruin the atmosphere. Having to look at my start button and taskbar gave the same feeling as when someone interrupts you during a real good book.
Play the damned game! But only at night time, and when it's silent and you're otherwise a little tired & relaxed and most of all by yourself. Perfect!