The sharp, funny first half of this adaptation of George Jung's self-serving autobiography is the Boogie Nights of drug movies.
After a deft sketch of a 1950s childhood, with a financially struggling father (Ray Liotta) and a mother (Rachel Griffiths) given to walking out when times get hard, the Californian beach scene of the '60s seems like Utopia. A hand-to-mouth marijuana trade mushrooms into a craze, as George hooks up - through his stewardess girlfriend, Barbara (Potente, unrecognisable from Run Lola Run) - with gay hairdresser/pot distributor Derek (Paul Reubens) and turns a casual racket into a real business.
Demme cheerfully deploys the familiar music samples and fashions, and Depp shows off a Shaggy-from-Scooby-Doo hairstyle that signals his usual willingness to disguise handsomeness under layers of goon make-up. The trade gets harder when George, ratted on by his hypocritical mom, skips bail to nurse Barbara through a sudden fatal illness and has to serve serious jail time. Inside, he meets flaky Colombian Diego (Jordi Molla), who introduces him to cartel kingpin Pablo Escobar (Cliff Curtis) and in no time at all he's banking thirty million dollars in Panama, snorting kilos of the white stuff, marrying colt-like Mirtha (Cruz) and realising (duh!) just how ruthless and violent his new partners are.
However, in contrast to Depp's last foray into the stoned generation, the non-judgmental Fear And Loathing In Las Vegas, Blow has to break off its party and gangster threads to deliver the heavy "bad drugs" message. The long, slow finish segues from professional and marital crack-up to self-pitying in prison, as we are supposed to care whether a recidivist gets visits from his daughter or not. One real shock: after Depp has shambled about in wasted make-up, we get a glimpse of the real George Jung. What his life has done to his face is a far more potent argument against drugs than all the script's my-family-hate-me whining.