Uncut Gems review – this sparkler's the most exciting film of the year

This sensationally good New York crime drama is rocket-fuelled with greed and crack-fumed with fear. It is directed by the Safdie brothers, Benny and Josh, who create something deliciously horrible, working with their longtime screenwriter-collaborator Ronald Bronstein. It conjures up the work of James Toback and John Cassavetes – and indeed early Martin Scorsese, who is an executive producer here. There is a consistency of purpose that their earlier film, Good Time, lacked. In its unforced, gripping, black-comic chaos, Uncut Gems resembles nothing so much as a super-violent, feature-length episode of Curb Your Enthusiasm.

The Safdies have cast as their leading man Adam Sandler who gives a glorious, career-best turn as a fast-talking Manhattan diamond dealer called Howard Ratner (dare we hope for a cheeky reference to the British jeweller Gerald?), sporting a black leather jacket, dark glasses, earrings and an ingratiating, unreliable grin. Sandler has been known for pretty crass comedies in the past, though polite broadsheet opinion traditionally makes an exception for his performance in Paul Thomas Anderson’s 2002 film Punch-Drunk Love. For me, that was a bit overrated, and in any case Sandler is far better here.

Howard is semi-separated from his wife Dinah (played by Idina Menzel – the voice of Frozen’s Elsa) and kids, though still importantly embedded in the Jewish customs involved in her family dinners. He has now installed his sexy, vocal-fry-toned employee Julia (Julia Fox) in a cheesily decorated bachelor apartment in the city. His diamond shop is a heavily fortified, sweaty and airless emporium, protected by a castle-keep system of inner and outer toughened-glass doors opened with a nerve-jangling buzzer.

Howard’s business is doing reasonably well, thanks to a middleman called Demany (great work from Lakeith Stanfield) who brings high net worth individuals from the world of music and sports into Howard’s store in return for a cut of the sale price; Howard takes his own commission for selling Demany’s counterfeit Rolexes as certified genuine.

Howard is looking to make a fat profit with an illegally imported black opal from Ethiopia, the equivalent of a “blood diamond” but a stone of mythical import and rarity that fascinates Howard’s biggest celeb customer: NBA megastar Kevin Garnett (playing himself) who is capriciously convinced that this is an anti-kryptonite rock that guarantees victory on the basketball court. Like vintage 70s horror, Uncut Gems begins with an eerie prologue showing this occult stone being discovered deep underground.

So things look good for Howard, but there’s a problem. He is a compulsive gambling addict whose habit is raging out of control – though part of this movie’s 70s feel lies in the fact that he is never described as an “addict” and never recognises himself as such. He has a sideline in taking customers’ valuable pieces of jewellery for supposed repair (a kitsch figure of the crucified Michael Jackson being a case in point) but actually using them as collateral for huge mob loans that he will then bet on pro sports: usually basketball, with which he is obsessed. And he is borrowing against future assumed sales or sure-fire gambling wins to make other bets or pay off other creditors. Howard is in very deep with an intimidating player called Arno (Eric Bogosian) whose man-mountain goons make an unwelcome appearance at his store.

Sandler’s superb performance shows how Howard has what amounts to a superpower – his optimism, his toxic gift of the gab, his deranged delusional cheerfulness and his refusal to be fazed or scared by things that would reduce ordinary people to jelly. There’s an incredible sequence on the streets of Manhattan – which the Safdies and their cinematographer Darius Khondji shoot with rangy, loose-limbed exuberance – showing Howard getting punched in the throat by one of his debt collectors and then, after a moment of traumatic wheezing, he goes on walking, talking, attempting to bamboozle his assailant with ersatz charm.

But Howard is robbing Peter to pay Paul, in such a way that Peter and Paul are eventually going to take turns holding him down while the other beats the daylight out of him. His whole life is a pyramid scheme of dishonesty, in which the victim is himself.

And all the time the film is in a state of deafening cacophonous uproar: the white noise in poor Howard’s head is displaced into the streets, the clubs, the sports arenas where his terrible humiliation is to be played out. It’s a cinema of pure energy and grungy voltage, and the Safdies make it look very easy. This is the year’s most exciting film. You can take that to the bank.

• Uncut Gems is released in the UK on 10 January.