Writer/director Damien Chazelle's script ruthlessly focuses on the relationship between mentor and student to the expense of all other potential subplots, exactly as Andrew's focus must be on his drumming. Love interests, parental relationships, student rivalries and even a court case are all elements teased but ultimately pushed aside to make way for the central dynamic. And what a dynamic duo these two are. Fletcher most closely recalls Full Metal Jacket's Gunnery Sergeant Hartman: a borderline-insane, merciless bastard who can't afford to have the second-best of the best on his team. Simmons is amazing in the role, convincingly nailing the weapons-grade asshole but never losing sight of Fletcher's humanity, no matter how deep it's buried.
Miles Teller is the real star though: required to shift from nervous, sensitive cry-baby to emotionless drumming machine while actually playing like a pro, Teller holds the film's tempo like the musician his character yearns to become. He and Chazelle sell Andrew's passion completely, as sweat is flung off his face and blood soaks through the plasters he's ineffectually wrapped round his blistered and calloused fingers. It's an incredible performance, and Chazelle uses it to force us to ask who's really out of control here - the possibly-psychopathic, chair-hurling teacher, or the student so bursting with energy and hungry for greatness that he'd risk his life to impress him?
You can argue the film's case at length if you like, and indeed it does suggest that success and perfection only make monsters of us all; it just seems to suggest that that's worth it. Fortunately it does it with skill and style and an absolute fucktonne of noise, and it's one of the most exhilarating experiences I've had at this year's London Film Festival.