Firstly, ignore the cover. I don't know where that image has come from but it's not from this film!
Inspired by the actions of the 1984 McDonalds shooter, James Oliver Huberty, this film follows an already-unstable character who begins to mentally breakdown after his wife is granted a divorce. He's fired from his job as a garage mechanic for totally dismantling a car engine (and laying all the parts out in neat little rows).
His big-shot brother owns a disused hotel, which he plans to turn into flats, but 'generously' allows his sibling to live there until work is scheduled to begin. Unfortunately for our protagonist, a local gang uses the place as a hangout, and don't appreciate his presence, so they begin to threaten him. Frightened, forgotten and alone, except for his teddy bear, the poor guy begins to lose his grip on reality, culminating in a killing spree.
A rather slow-burning film for those used to a lot of action, but stick with it. It brilliantly handles the mental breakdown and you genuinely feel for the poor guy who seems to have lost everything in one fell swoop.
Geeks like me who read about real-life killers will also get a kick out of it.
Highly recommended