Jonathan Romney on Luhrmann's The Great Gatsby: Leonardo DiCaprio gets lost in Baz's jazz

It's all over the place – but there is much to savour in this irresistible adaptation

Like it or not, there couldn't be a more appropriate opening attraction for the Cannes Film Festival than Baz Luhrmann's 3D The Great Gatsby. The extravagant Jazz Age festivities that Luhrmann organises embody exactly the glamorous image that Cannes likes to project, while, conversely, the movie's sparkling soirées owe less to actual 1920s America than to a platonic fantasy of an eternal, orgiastic Cannes gala – palm trees, red carpets and all.

Never mind that Gatsby doesn't work by any conventional standards as an adaptation of F Scott Fitzgerald's novel. It achieves what it's after, establishing a benchmark for what cinema can be as lavish spectacle in 2013. Here's an opulent special-effects movie that, for once, is about a different kind of superhero. You won't be bored, and you won't be unimpressed – even if you find Luhrmann's hysterical exuberance fairly indigestible.

His Gatsby is not the slim Penguin paperback you know, but the leather-bound, gold-embossed interactive edition with built-in boom box. It's so hyperbolically madcap that you want to take Luhrmann aside and say, "Now calm down, old sport …" Take the moment when Jay Gatsby first appears, at one of his parties. In the novel he self-effacingly turns up in the crowd; here, Leonardo DiCaprio toasts the camera with raised champagne glass, as Rhapsody in Blue hits its climax and fireworks blossom behind him.

Controversially, Luhrmann depicts the 1920s as the age When Bling Was King, using hip-hop style to draw comparisons between two periods of artistic creativity and of social and financial excess. Hence a soundtrack overseen by Jay-Z, featuring thunderous R&B rhythms over period newsreels, rappers in cars laden with crates of Moët (should have been Cristal, surely), snatches of Beyoncé and Florence Welch … And it sort of works – that is, it's distracting only up to a point, but never fully makes its impact. Rather than go all out with anachronism, as in his Moulin Rouge, Luhrmann patches little funky surprises into what's otherwise a surprisingly faithful adaptation, unambiguously set in the 1920s.

The style, though, is pure Luhrmann. Simon Duggan's camera bombs over the waters of Long Island or plunges off skyscrapers, like King Kong taking his final dive. In the novel, a drunken get-together in a Manhattan apartment is a crisply acrid comedy of manners; here it involves pillow fights, slapped buttocks and screaming red decor.

When they come on all visionary, Luhrmann and his partner, producer and designer Catherine Martin, lay it on with a gold-plated trowel. Gatsby's mansion is a Ludwig of Bavaria castle with the Gardens of Babylon attached. By contrast, the "valley of ashes" between Manhattan and Long Island becomes a benighted backwater of hell, its denizens ragged Orcs with soot-smeared faces.

The actors, understandably, can get a little lost, but Carey Mulligan's Daisy is a reassuringly candid presence – weary, wan, with a dash of Blanche Dubois. Also impressive, and perfectly period, is Elizabeth Debicki's golf gal Jordan – wide-eyed and angular, as if a gazelle had been crossed with an Afghan hound and hadn't recovered from the shock.

Bollywood legend Amitabh Bachchan is the shady Wolfsheim, here a Pharaoh-like corsair. Least impressive is Tobey Maguire's narrator Nick Carraway, disappointingly painted as a straw-hatted goof.

Best of all, though, is Joel Edgerton, whose racist boor Tom Buchanan transcends the monstrousness to achieve genuine vulnerability in the one scene (his confrontation with Gatsby) that achieves dramatic resonance. But the usually compelling DiCaprio never comes into focus as Gatsby – one minute the suave châtelain, the next manically yelling his biography, then suddenly a confused dork in a too-farcical tea-party reunion with Daisy.

The stylistic lurches make for a messy, incoherent film, but think of Luhrmann as approaching the novel the way that some crazed avant-garde opera director would treat the Ring Cycle – a bit of post-modernist outrage here, back to trad Wagner there, and the devil take the hindmost.

The result might be a travesty of Fitzgerald's ironic grace, but as a celebration of what CGI-age cinema can be at its showiest and most fanciful, I'll take it over your usual blockbusters. Think of it as The Fast and the Furious: The Jazz Generation.