Perfect cast and a good story

This is one of the few movies I've ever seen where the whole audience broke into spontaneous, loud applause a third of the way in.

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.

All of these films share one commonality, that being a kind of emotional center that humanizes a cast of monsters.