(CNN) -- Hunter S. Thompson's slim early novel -- written in 1959, when he was 22, but only published 40 years later -- gets a dream screen treatment courtesy of producer-star Johnny Depp and "Withnail and I" writer-director Bruce Robinson.





By rights Depp -- who already played Thompson's alter-ego Raoul Duke in Terry Gilliam's grandly grotesque "Fear and Loathing in Las Vegas" -- should be too old to play the latest recruit on a failing American newspaper in San Juan, Puerto Rico.





But even when he's hung over and wretched (which is often) he easily passes for 30, the age of the book's "Paul Kemp." Of course the fact that this engagingly left field movie has spent three years on the shelf helps.





When Kemp washes up in San Juan, his greatest literary achievement is his resume. He's promptly put on the astrology desk. But he's hungry to make a name for himself, which gives him an edge over his pickled colleagues. It's enough to attract the patronage of local wheeler-dealer Sanderson (Aaron Eckhart), a property developer who has big plans for the island -- and his eye-catching girlfriend, Chenault (Amber Heard).





It would be an exaggeration to call "The Rum Diary" a dry run for "Fear and Loathing" (and "dry" wasn't really in Thompson's vocabulary, though Kemp does make vain promises to cut back on the hard stuff from time to time). Still, in Depp and Robinson's hands you can't miss the roots of Gonzo. This is more than ever the portrait of the artist as a young man -- fermented, refined and distilled from the book.





Compared to his cartoonish Raoul Duke (or his Jack Sparrow) Depp's agreeably deadpan performance is scaled back several notches, though it's hard to think of another movie heartthrob who uses his body to such clownish effect when the occasion arises. Frequently shuttered behind a slick pair of shades, Kemp is a stranger in paradise and not quite sure of his bearings yet. He's an avid observer trying to figure out where a real writer might fit between the stinking shantytowns and the shiny luxury beach houses.





Robinson has no doubts about which side he's on in that fight, and smuggles in pertinent asides on the parlous state of today's heavily mortgaged newspaper business. Vibrantly photographed by Dariusz Wolski, the movie lays on the local color with gusto -- we get fighting cocks, voodoo and carnival - but we also see broken down plumbing, simmering racial tension, permanent flop sweat and killer lines like Sanderson's, after Kemp marvels at the beauty of the place: "It's God's idea of money."





Admittedly Kemp's picaresque misadventures don't add up to much of a plot -- the wheels come off in a climax that slouches off miserably in search of some future happy ending -- but there's so much to enjoy along the way, the movie's delayed release is hard to fathom.





Depp's easy rapport with Michael Rispoli, as photographer/sidekick Sala, is a low-key delight. I loved the way Aaron Eckhart's imperious uber-confidence slips where Chenault is concerned; and even anomalies like a jewel-encrusted tortoise... "I got the idea from a book," Sanderson explains -- as if it did.





Bruce Robinson has never topped the riotous comic miserabilism of his first film, the cult classic "Withnail and I" -- he's never even come close -- but "The Rum Diary" might be considered hair of the dog after a 24-year-long career hangover. He's back in his debauched and debunking element, which is reason enough to celebrate.
Who's performance was agreeably deadpan? Who did Depp rapport with? What does the movie do with gusto?
Johnny Depp Michael Rispoli, lays on the local color
question: Who's performance was agreeably deadpan?, answer: Johnny Depp | question: Who did Depp rapport with?, answer: Michael Rispoli, | question: What does the movie do with gusto?, answer: lays on the local color