Nothing is really special about it. The graphics look nice in some parts, bland in others. The gameplay is pretty repetitive with the hack, slash, finish, but luckily, you can dodge enemies. Insanity is great the first few times, but later it gets annoying, especially the wailing.
But the one factor that redeems this game above any other game is the great story. I have never been immersed or engrossed with another story in any videogame. The ambience, music and sound effects are top notch as well. The puzzles, while simple are clever, so I won't complain here.
The story is mainly what makes this game great, and sets it apart from any other game.