Bought it a couple of hours later based on your review joomongj.
This game will indeed scare the living daylights out of you, definitely the scariest game I have ever played.
You are stuck in a (dark, ominous) castle with no idea where you are, why you're there or even who you are. You have limited light sources (an oil lamp for which you have to constantly find oil and tinderboxes to light candles) and being in darkness will make you go insane. Going insane involves hallucinations, difficulty walking and probably worse (I haven't gone too insane yet).
The atmosphere in the game is absolutely brilliant. If you step out from the light into the dark, your eyes need to adjust to the dark (just like in real life). The setting of a dark and ominous castle is excellently worked out in the effects and music. Creaking doors, sounds of footsteps above you, monster screams around the corner or in the next room, visions of monsters (or hallucinations?), people begging for their lives (are they real?). When you see or hear something scary, not only do you get scared, your character actually gets scared himself. You look around shiftily, your character whimpers and you hear a pounding heartbeat.
And sometimes you actually run into monsters. How do you fight them, you ask? You don't. Simple as that. There are no weapons in the game. The only way for a showdown with a monster to go down is for you to run, hide or die. Where do you run and hide? Into darkness, like a cupboard you close behind you in a dark room with the monster breaking the door and audibly breathing just feet away from you.
I know this probably doesn't sound all too scary, but it really is a terrifying game if you immerse yourself into it. I only play it at night for example. Survivor horror at its best. I know I've been hiding in a cupboard for minutes just because I thought I heard a monster.
9/10