I'd definitely rather clean the cat box than see this again.

By my definition of horror, i.e. not unrelenting gore, this was a disappointment. In fact, the first time that I tried to watch it, the two guys in the room revolted within the first 15 minutes and refused to watch any more.

Foolishly, I decided to rent it again and watch it alone. Yes, there is a twist and it is a surprise. Otherwise, from the opening scenes, this film is relentlessly nasty, gory, and really not very interesting--I fast forwarded through most of it so that I did not have to hear (or watch) the screaming. So, unless it is a free rental and/or you get off on human-on-human violence, expect to pay a rental fee to see the beginning and then fast forward through to the surprise ending.