In the unimaginable event that you haven’t had the date circled on your calendar for months, Friday marks the US release of Gotti. An authorised John Gotti biopic, eight years in the making, starring John Travolta as the late mob boss, the film has weathered more bust-ups than many a low-rent mafioso.

It passed through the hands of multiple directors, including Oscar winner Barry Levinson, before trickling down to Kevin Connolly, the maestro perhaps better known for playing Eric “E” Murphy on the HBO bro-fest Entourage. (Yes, he’s made films before: who could forget 2007’s Gardener of Eden, a Tribeca premiere still awaiting reviews on Rotten Tomatoes?) Al Pacino, Joe Pesci and Lindsay Lohan all flitted in and out of the ensemble. And last year, 10 days away from its scheduled opening through distributor Lionsgate, the film was pulled: producers, deciding they wanted a wider release than the one the studio cautiously had in mind, exercised the buy-back clause in their contract.

As an industry rule, this kind of Hollywood backstory does not tend to augur an artistic triumph, even with the fairytale twist of Gotti securing a last-minute premiere slot at the Cannes film festival. (More on that dubious turn of events later.) And unless you’ve come to Gotti for anything but the bizarre quasi-camp spectacle of Travolta channelling the Teflon Don via Tony Soprano via the Dolmio dad – in a truly dazzling array of crunchy-looking wigs – it’s fair to say Connolly’s lurid Noo Yawk story doesn’t disappoint. But its failings are rich and varied, minor and major; just as Gotti himself eventually went down on 13 charges ranging in severity, let’s list the film’s offences in roughly ascending order of egregiousness.

Punctuational negligence

Yes, we’re starting small, but it’s a nagging error all the same: natural-born proofreaders will note that hyphens have gone awol from the film’s opening credits for its numerous “co producers” and “co executive producers”. Admittedly, Gotti is not a film overly preoccupied with the niceties of language, but this does not bode well for its sweating of the larger stuff.

Geographical infidelity

“Lemme tell you summin’ – New York is the greatest fuckin’ city in the world … my city.” These are the first words Travolta-as-Gotti mushmouths in the film, turning toward the camera from a nighttime view of the Brooklyn Bridge that looks awfully rear-projected. (Immediately afterwards, he tells us he’s speaking from beyond the grave, so perhaps that’s what the Big Apple looks like from his undead purgatory, but let’s tackle one problem at a time.)

This tour guide introduction, further accompanied by establishing shots of subways and the East river, may be pure processed cheese, but it’s also the clearest indication we get of where the film’s set: shot predominantly in Cincinnati, against a rotating backdrop of anonymous suburban blocks and brown back alleys, it evokes Gotti’s beloved city about as authentically as Taylor Swift’s Welcome to New York. Later, when a mobster alludes to “the support of all five boroughs”, the script actually makes him list them, just to be sure.

Prosthetic inconsistency

Give Travolta this: he goes through a journey in this film, playing Gotti from a 30-year-old underworld underling in soft lighting and a vinyl-like hairpiece to a bald, cancer-riddled septuagenarian with, in his own parlance, a “tit” surgically sewn on to his chin. The makeup team see him through with flamboyant enthusiasm – so why does Spencer Lofranco, the swaggering 25-year-old tasked with playing Gotti’s eldest son and criminal heir, not benefit from any of their attention? Lofranco changes not a whit as he plays Gotti Jr from advanced-looking teendom to baby-faced middle age, oddly saddled most of the way with a Macklemore-style undercut that his real-life counterpart never had to begin with. The film’s flip-flopping timeline is messy enough as it is: at least age your characters at the same pace.

Casting-department nepotism

No surprise that Gotti is not rich in well-developed female characters, and the role of Gotti’s wife Victoria, running the gamut from shrill to pill-popping to shrill again, is not one that would have leading actresses queueing around the block. So you could say Travolta’s wife, Kelly Preston, making her first big-screen appearance in eight years, did hubby a solid by taking it on. Either way, neither she nor the role are helping each other: her tactic of slavish Lorraine Bracco impersonation is a thin one, though given how the film around her is throwing Goodfellas poses in the mirror, she’s at least on-message.

Irresponsible Pitbull handling

Yes, Connolly’s Scorsese karaoke routine may extend to a jukebox-rock soundtrack running the gamut from Aretha Franklin to Duran Duran, but that hasn’t stopped the director enlisting the services of Armando Cristiano Pérez – better known to Top 40 pop-rap aficionados as Pitbull – to compose the film’s score, throwing a few of his own numbers into the stew. What Latin hip-hop has to do with the world of Gotti is open to question, but then you could say the same of Kevin Connolly or Kelly Preston: embrace the fusion. Alas, there’s no shootout staged to Pitbull’s jolly Kesha duet Timber, and his original rhymes find him dourly off his debatable game: “There’s rules and codes / Won’t break ’em for no one / Unless you’re a fool / Like that fucking prick Sammy the Bull,” he spits over the opening credits. Against such songsmithery, we’ll let his instrumental scoring slide, though much of it evokes a Casio keyboard on the funk-porn setting.

Croisette coercion

The Cannes film festival has lent its official stamp of gilded prestige to some dubious films in the best of years – hello there, Grace of Monaco – but perhaps never one quite as shonky as Gotti, which eventually got quietly shuffled into the lineup mid-festival, discreet and embarrassing as a silent fart in an elevator. Cannes did its best to downplay its presence – it was given a single screening in one of the festival’s smallest screening venues, with no press show or red carpet preamble – but there it was anyway, with festival director Thierry Frémaux grimly introducing Travolta and John Gotti Jr as guests of honour. What gives? Could it have anything to do with the festival already having scheduled a master class and beachside Grease screening with Travolta? Did the star, also one of the film’s producers, suddenly add an official premiere to his festival rider? Hard not to smell an underhand power play worthy of Gotti himself.

Travolta terribility

As they say in Scientological circles, Xenu loves a trier, and he must love Travolta more than most: 40-plus years and multiple comebacks into his career, the star’s still lovably chugging away, giving his all to projects that don’t even deserve his quarter. He’s been dynamite in roles that play on his dorky-cool magnetism, but never as a pure hardman: as Gotti, he poses as unconvincingly as he did as a hench hitman in From Paris With Love, pursing his lips to denote steely conviction and blitzing vowels into a Mickey Blue Eyes drawl (“Ah’ll pock a bus up yo’ ass fockin’ sidewez”) that belies his own nearby New Jersey origins. As we also saw recently with his wobbly Robert Shapiro in The People vs OJ Simpson, biographical impression is not where Travolta’s twinkly talent lies.

Grievous hagiography

Finally, Gotti’s shabby aesthetic and narrative shortcomings are outweighed by its more drastically questionable moral ones. Connolly’s film may be the first mainstream mafia biopic to overtly take the underworld’s side in its rise-and-fall story: a sympathetic stance was to be expected given that it’s adapted from Gotti Jr’s own self-published memoir, but it’s still somewhat startling to see the film-makers fully buying their subject’s account of events, from its portrayal of Gotti as a doting family man, the bulk of whose criminal acts are kept off-screen, to its chastisement of the government for alleged ill-treatment of the Gottis during their respective trials, to an inadvertently hilarious closing montage of real-life supporters singing the Don’s praises (“Everybody knows he was a good man”). And that’s before our man Pitbull conclusively raps his praises as the credits roll: “Dapper Don / I called him Dad / Giant in my eyes / Legend of a man”. If a certain other contentiously powerful New Yorker is commissioning a biopic any time soon, he might want to check this out – Travolta as Trump, anyone?

• Gotti is now available in the US and will be released in the UK on 17 September