People are saying that this is the worst film they have ever seen and that the camera work is really bad, and to them I say: "What is wrong with you?"
This film is filled with tense, suspense filled action which will have you biting your nails, wanting to know more. The camera work, using a supposed hand-held video camera makes this film that much better, with the fact that you know as much as the main characters, and the fact that it gives a first person perspective on the whole happenings of this film.
It has an original storyline, and is excellently crafted, and believe me, after the film ends, you will be wanting to know more and more. Personally, after watching this film, I was jumpy and scared, it was that realistic and good.
To be fair, however, the first 20 minutes of the film are really boring. Basically, the first 20 mins or so explain the lives of two characters and the setting up of a party about to happen. Believe me, skip this part.
But after that, you get dived into the action, and so, overall, this intense film is well worth watching. Don't shun the film, judge it after you've watched it. I personally loved it, but this film is like Marmite - it's either loved, or hated.