I heard it was pretty hardcore and during the first seconds, they give you some quick flashes about what will happened so I was warned but, still, what an ordeal! There were here some really violent sadistic gore scenes and the movie was slightly going towards the torture porn (such as 'Hostel', 'Saw', ...) but they still managed to stay away from that genre. The main difference was that the whole plot was actually pretty realistic and the story described something that could actually take place which was pretty scary when you think about it. Furthermore, the characters were pretty well written and I could easily identify with them. Kelly Reilly and Michael Fassbender (one of the fast rising stars nowaday), both delivered some strong and convincing performances. The 'kids' were terrific as well, in every sense you can possibly imagine. So, I liked this flick but I'm not sure if I can recommend it. Indeed, the whole thing was pretty hardcode and, at the end, I even felt a little bit nauseous, so if you are sensitive, I would advise to avoid this one. To conclude, I think it was a a decent watch and it is definitely worth a look, especially if you have a strong stomach and even more if you like the genre.