Good concept, poorly executed.

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.

The movie's not perfect, but it sticks the landing of its message. It was engaging - thrilling at times - and I personally thought it was a great time.

I think this is a new genre that they're all sort of working their way through it and haven't got all the kinks worked out yet but it's a genre that works for me.