The lack of music, and the ambient sounds of the house, footsteps, ghostly calls, and such, really add to the fear factor for this game.
The main characters (you play as a different character for the intro, and then the main character for the rest of the game) move v...e...r...y s...l...o...w, but it adds to the effect that the game is trying to convey.
Real time shadows from your flashlight really make the backgrounds jump to life, especially when it appears the the shadows are something else moving ahead of you...
All in all, I suggest at least renting this game, it'll scare the daylights out of you. As another note, if you pause the game for a while, bloody hand prints appear on the screen and dissapear, which actually creeps me out.