Having no real idea what the movie is about, I came away rather liking it a good bit. It's a mix of horror and action and some nice character driven stuff too. It's pretty simple at what it does, but does it effectively. No complicated story, just a short concept and it takes off from there. Lots of good tension and scares throughout. If your wanting to see a good show, check this out, if not it would be an awesome rental.
