Lack of good storyline.

The film makes a home in your brain and the only cure is to see it again.

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.

This is one of the best movies I’ve seen in a very long time. You have to go and see this on the big screen.