It’s a big risk calling a movie Blow. Headline writers, pressed for time and happy for puns, are prone  to turn even a mildly negative review into groan-inducing one-line summaries: “This Blows,” “Blow Sucks.” Low blows, indeed.

Happily, Blow (based on Bruce Porter’s book of the same name) has enough merit to avoid easy aphorisms. The title refers to cocaine, but Blow isn’t intended to be a drug movie in the sense that Traffic or Trainspotting are drug movies. It assumes its viewers already know the history of coke and how the drug took Studio 54 and Wall Street by storm, and thus steers away from dealing with the well-documented social effects of cocaine. Instead, the film is a biography of an extraordinary life, that of George Jung, the baby-faced Massachusetts native who went on to become the American connection for the infamous Colombian drug lord Pablo Escobar, and the movie’s chief merit is the casting of Johnny Depp as Jung. If you did blow in the late 1970s or early 1980s, there is an 85 percent chance your coke spoon held the products of Jungian pharmacology. While Depp spends altogether too much of the film hiding his expressive eyes behind sunglasses, his Jung, simultaneously ambitious and laidback, bursts with enough charismatic energy to convince us that this small-town boy without many connections was the one who made cocaine a major drug in America.

Jung was, as they say, a character. So how do you film the life of a man larger than life and make some sense of it all? Director Ted Demme (Life, Beautiful Girls) answer is to use editing and camera effects to create a kind of hyperreality. As in Traffic, filtered lenses indicate time and mood, so scenes on Manhattan Beach in California appear sun-bleached, almost sepia-toned, while the sex scenes between Depp and Penelope Cruz (All About My Mother) are red-hued. (Steven Soderbergh may have started a trend in the drug-movie genre. Cheech and Chong might want take note.) Freeze frames indicate the passage of time.

Using these devices, the movie traces the arc of Jung’s life, starting from his childhood in Weymouth, Mass. in the 50s all the way to his present incarceration in a federal prison in Otisville, NY. (Aside: why is a 33-year-old woman, even one as talented as Rachel Griffiths, playing mother to a man five years older than her?) Everything seems to be right for Jung just after he leaves Massachusetts for California: He meets flight attendant Barbara (Franka Potente, of Run Lola Run fame) and gay hairdresser Derek Foreal (Paul Reubens, once known as Pee-Wee Herman, in full-on camp mode). Through Derek, Jung becomes a small-time pot dealer on Manhattan Beach, but his dreams are bigger, and he flies into Mexico to the source of the marijuana. The good times roll—with the profits from dealing, Jung and Barbara buy a house in Acalpulco—and this first half of Blow is almost Edenic: everyone is friends with everyone else, money is plentiful but doesn’t engender greed, people take dips in sun-kissed swimming pools.

The arrest of Jung in Chicago is the movie’s point of innocence lost. After his hearing, Jung learns that Barbara has cancer and skips bail to be with her, the first sign of a devotion to people that will be a constant theme in the movie. Jung is arrested after Barbara’s death and thrown into jail, where he shares a cell with a Colombian, Diego Delgado (Spanish actor Jordi Molla, making his American feature film debut). Upon Jung’s release, Diego introduces him to Pablo Escobar (Cliff Curtis). It’s not the most pleasant of first meetings—Escobar shoots someone point blank in the forehead—but Escobar takes a shine to the American and makes him his chief importer of cocaine into the U.S.

As though paralleling the shift in drug trends from mellow pot to frenetic coke, the movie pulls into high gear once Jung and Diego go into the cocaine-import business. (A second aside: Does the schizophrenic nature of the movie mean to imply “pot good, cocaine bad”?) Jung meets Mirtha, played by Cruz in thoroughly unsympathetic fashion, and the two begin a torrid relationship, all wild sex and drug binges. The money that accompanies the cocaine business causes a string of problems: betrayals occur left and right, friendships are broken and the now-married Jung and Mirtha fight constantly. The marriage does produce Kristina Sunshine Jung (Emma Roberts), the daughter who gives Jung meaning in his life. Jung’s love for his daughter provides a note of poignancy in the later arrests in the movie: Whereas previously jail seemed more an inconvenience or an occupational hazard, the enforced separation from Kristina is truly painful for him.

It’s fascinating stuff from a fascinating life, and Demme coaxes strong performances out of a stellar ensemble cast. (He’s done this before: I’d be the first to admit that I find Beautiful Girls very moving.) Memories of The Ninth Gate notwithstanding, Depp is very good as always, while Cruz does her best with the flat character that is high-living Mirtha. Potente is sunshine and charm, even if her German accent does creep into one scene. Ray Liotta gives a performance of grace as Fred Jung, George’s father, a man who doesn’t necessarily approve of his son’s choice of careers but understands. There’s also lots of smart things to like about Blow. The soundtrack (including Cream’s “Strange Brew,” featuring Eric Clapton in his cocaine years, and the Rolling Stones’ “Can’t You Hear Me Knocking”) is clever enough to fuel the movie without overpowering it or being too obvious. The aforementioned editing and camera effects add to mood but aren’t overly gimmicky. The ending, featuring a wizened, incarcerated Jung, is a heartbreaker.

Despite all that, something doesn’t quite sit right about the film as a whole. Maybe one too many drug busts inures the viewer from the meaning. Maybe Demme tries to pack too much of Jung’s life into one movie. Either way, outside of the genuinely moving George-Kristina scenes, there’s too much of a detachment from George Jung. While Jung’s very name might seem to invite psychological analysis of the man, the movie never shows us why he does what he does, or why he is so ambitious. There’s the implication from the childhood scenes that Jung never wants to have to work as hard for as little as his dad, but other than that, the film seems to suggest that the inevitable logic of capitalism works this way, that somehow the very fact of being American causes Jung to be entrepreneurially ambitious, to spot an opportunity to make money. But why Jung and not anyone else? Why is he always reaching for more when he doesn’t seem to be a man of particularly extravagant tastes? True, greed has its own logic, as does accumulation and the high of the next big deal (there’s a great scene where George and Diego are raking in so much money they begin judging the amount of cash they have by weighing boxes of hundred-dollar bills). But that’s too pat an answer, and for a biographical movie Blow gives us little insight into its lead.