The ending (contains spoilers)
I found this a totally engrossing film, but I think that the last scene (at the prison) should have been left out, because why would Jamie just go and totally reject his father like that? Granted, his father is an evil bastard - but as the events of the film transpire, it eventually becomes obvious that he had nothing to do with the attacks on the two girls in the film; and he hadn't done anything that I could see that would obviously upset Jamie.
I'm not saying Jamie isn't better off without him in his life - just that from the point of view of a 15 year old who up till that point seemed to have been getting along well with his father, it struck me as being out of character.
Plus it would have left a bit more of a 'mystery' at the end as to what might happen next, rather than have it all explained neatly.
Does anyone else agree/disagree?