The woods are scary. It's something instinctual to the human mind that the woods is a place to be on high alert.
This movie depicts a walk in the woods. For 98% of its runtime, that's all it is. Anytime the scenery changed, I perked up. I can tell that there's a definite tendency toward what I can only assume is "art" with the shots in the film. I like to look at trees. I don't like to watch a movie that promises horror and is somebody just being lost in the woods. Blair Witch worked because there were several characters. Much of this film is made up of our near-silent protagonist wandering. Don't get me wrong, it's much better than listening to Shia Lebouf jabbering about everything and nothing.
You aren't allowed to see anything. Ever. So if you want to see something scary, this isn't the film. I'm not sure who I would recommend this movie to. The woods are scary. You can see things in the trees and shadows. Watching someone lost for an hour and a half is not a horror movie.
Side notes: I can only assume the Acts and Chapters with the titles were inspired by House of Leaves (another example of something overly long and boring for a good idea), but don't pair the two up. Just stick to acts and scenes. Don't try to reinvent the wheel.