good back-story, and good acting

I was totally surprised at how great this film.You could feel your paranoia rise as the film went on and as you gradually learned the details of the real situation.

In truth, there is barely enough story here to make a film.

Watching it is like watching the spectacle of a class clown at their best: you laugh at their jokes, instigate their defiance, and "ooooh" when they get in trouble.