Nice effects though.

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.

Strong acting helps the film overcome an uncertain premise and create characters that hold our attention absolutely.

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.