First of all, I recommend playing this game. Has amazing graphics, and little touches that really engross the player in the game. These little touches take the game to the next level. Things like, seeing your own limbs as they move, hearing footsteps/breath, motion of objects when you walk into them (such as bookcases, they sometimes fall down as you walk into them). All these things make take the game to another perspective of gaming. I've played realistic games like COD2, which are amazing, but this game is a step above.
Due to the realism of the game, the twisted story, and creepy goings on make the game seems a hundred times more scary than it actually is, which is a credit to the programmers and writers of the game. They have turned a moderately scary game into a first class horror movie.
The game also involves enhanced AI features from computer opponents, enhanced realism during firefights, shrapne/dust/projectiles etc.
However, the firefights seem a bit too easy with the added "slo-mo" addition. I managed to complete the game of the extreme setting, in several sittings due to the horror of the game, while only dieing about twice. Things happen time and time again that set you back also. Was looking forward to having some guys on my side, but they get "mysteriously" killed, or I fall down a shaft or something?!?!
Amazing game, but doesn't have much replay value, due to anxiety through knowing where scary bits are, or just the fact that things are too predictable!