Lack of good storyline.

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.

There is, somehow, an interesting story here, as well as some good acting. There are also some good scenes

It is encouraging that the film ends so strongly.Otherwise, it wouldn't have been a particularly memorable film