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.

It's entirely possible that sending the audience out feeling lousy was intentional

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's the kind of movie you'll want to see a second time with someone who hasn't seen it yet, to remember what it was like to watch it for the first time.