I really enjoyed this film. I thought the story was believable and held me throughout building nicely to a well-anticipated climax. The characters were well contrasted and whilst they seemed to represent obvious 'good' and 'bad' qualities they were also complete enough to provide for an absorbing and thought-provoking interplay. They also appealed well to my natural affections and disaffections as well as to my sense of justice. Billy Bob Thornton was brilliant as the 'retard' Karl. Bearing in mind he also wrote the screenplay and directed the film one can only say it was a real tour de force.
I'd like to say "Thank you" to the people who gave Billy Bob Thornton the backing he needed to get this great story onto our screens. I was watching in fascination as the story developed & I marvelled at his portrayal of Karl. Since this one was made, he's gone on to win praise for many more films but I hold this up to be his best.
Footnote.
American child actors (like "Frank" in this film) are far more skilful than their British counterparts.