Don't listen to the negative reviews
A great movie, one of the best of this year. There was a bit of confusion at one point in the plot, but nothing serious.
The film never slows down or bores, plunging from one harrowing sequence to the next.
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.