I think it is important to be aware before you go into this film that it is most definitely a drama and not really a thriller. I think most of the sub 5 star reviews have seen the thriller tag and thought that was what they were going to get. This is a serious drama about child abuse and how it can affect everything and everyone around you and is a brave movie if I may say that.
If you are feeling depressed or are expecting something else then I would walk away now and find something else to watch. You definitely have to be in a certain mood to watch this and take it in properly.
The acting from the entire cast was superb especially Alex Pettyfer who carried the movie and directed it but also a scintillating performance from Nicola Peltz and Hala Finley.
The subject is a serious one about child abuse in America and I think how widespread it is around the entire world and gives one pause for thought and to ask questions of the audience which is a good thing. However if you are not in the mood I do not think you will find this an enjoyable experience as it will leave you with a good few dark questions and is not conducive to alleviating your mood if you are in any way feeling down or depressed.
That said its a brave subject to tackle and make a movie about knowing full well that 80% of audiences will not like it and prefer the crash, bang, wallop that society seems to focus on these days which is a shame.