The Ending
First, I like this movie. I like the idea that if you really want to make someone suffer, you don't kill them but rather you let them live after destroying their life. Yes it has a good bit of violence but this is a violent tale.
My problem with the ending is that Blake is an apparently super tough white aryan who can easily defeat the most hardcore prisoner, yet basically gets his ass kicked by Styles on that tower. Styles is muscular, but he is nowhere as big as the character played by Jessie Ventura.
Another thing is when Styles gets his arm impaled. He comes down from the tower and his arm is not bandaged and he hugs his wife and moves that arm like nothing happened to it. He should have been bleeding quite heavily and they should have bandaged his arm and loaded him into an ambulance.
In short, I suppose I expected a less one-sided fight and Styles for the sake of continuity should have barely come out alive after his fight with Blake.