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.

It is neither dumb nor smart enough to be fun, and spends way too much time with its boring human characters.

The film never slows down or bores, plunging from one harrowing sequence to the next.

This is a small, humorous movie in some ways, but it has a huge heart. What a nice experience.