This is a good film in its own right, one that plays around with the "Big Brother" concept and tells a very good story with a strong cast and a well-paced plot. The problem with this though is that it's a horror film that isn't scary, it probably could have benefitted from being promoted as a satirical thriller because I was never once scared whilst watching, which was a disappointment. The ending was OK but it could have been better, it didn't really feel like an ending at all, more of an invitation for the film to continue with it's new twist.
I do recommend this film as it is enjoyable, but if you want something similar that I would say is a lot better then watch 'Cabin In the Woods', a film that goes full throttle with its satire and tongue-in-cheek campiness, whilst not scary either, it was promoted more as a sci-fi/horror/satire parody and thus delivers its message more clearly.
Also, see if you can spot a small supporting role from a young Bradley Cooper in this flick, the man who, 10 years later, would get an Oscar nomination.