I watched this with a group of friends and we were bored with it. We found the story line boring and predictable. (Figured out blind people played into it about halfway through). Didn't explain - whatever it was - the dark evil very well outside of a minor characters ramblings about his internet conspiracy theory, end of the world mumble jumble. From the opening scenes you knew that no one she started out with in the house was going to survive - surprise!
Sorry, this movie was not up to the mixed hype that I've been hearing and reading about it.