A brilliant film that helped define a genre

While it doesn't offer any answers, it both thrills and makes you think.

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.

Unshakable, witty and deeply felt, the film will be paying emotional dividends for a long, long time.