It is a good movie the concept is very strange and confusing at first and it doesn't give you many hints on whats going on so it draws your attention cause you want to know more. It is more of a physcological horror cause there is no visual images that are scary. And in my opinion phycological horror is the scariest horror because it messes with your mind and makes you anxious.I think it is the type of movie that you yell at the screen while watching because of the tactics and reasoning people use for wanting to kill of that person. Overall it is a 4/5 star movie because I wish the ending had a little more explanation, but in a way that is what summed up the movie. During the movie I was not as scared as I was after the movie because there is just so many possible explanations and endings to this movie, it is a total mind bender, but definetly worth watching.