Instead, you get a movie that's enjoyable enough, but leaves you feeling like it could have been much, much more.

I really wanted to like this movie. I feel terribly cynical trashing it, and that's why I'm giving it a middling 5. Actually, I'm giving it a 5 because there were some superb performances.

It's funny, it's tense, it features two great performances from two actors and the director expertly creates a web of odd tension where you actually don't know what is happening for the majority of the run time.

One of the most extraordinary films you will see this year. Take that as you want.