It's not great by any means, but it's a pretty good movie that didn't leave me filled with regret for investing time in it.

Simple and well acted, it has tension enough to knot the stomach.

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.