The 'Pshychologist'
Ruined the film. It is easy to play psych doctor with hindsight - all that he was doing was narrating one-step ahead with poor analogies and metaphors and often getting himself mixed up and straight wrong.
for eg. Montgomery says after the killing 'I couldn't let an 18-year old get the better of me'. The psychologist analyses this as Montgomery taking up the personality of a young marine sniper and eliminating his 'competition' (*eye roll*) when it is obvious that by referring to the victim as being 'younger' he is referring to him as the older, real, Montgomery.
I thought about it afterwards, he is everything that is wrong about this film. Take him out of it and replace it with an inter-woven story narrated by family members, the victim, friends (why was nobody else from the factory interviewed?) and you have a great film.