If you didn’t know The Nice Guys was a Shane Black movie, his signature’s visible a couple of minutes in. A teenage boy in 1977 L.A discreetly removes a skin mag from its hiding place under his parents’ bed and drinks in the voluptuous form of fictional porn star, Misty Mountains. A moment later, a car runs off the road, through his house, and into the adjacent valley. The driver, thrown clear, and shorn of her clothes in the process, is none other than Misty Mountains, who lies dying while displaying her live assets to the awe struck teen. The punchline? “How do you like my car?” Therein you’ve got everything you need to complete your Black bingo card – sexualised minors, improbable histrionics, excess and irreverence. It’s a series of cues, if you weren’t familiar with the pedigree, that Black’s movie is not going to be Chinatown, or even the tongue in cheek stylings of Robert Altman’s Long Goodbye. This movie’s going to be lewd, crude, silly and lip curling – cartoon pulp.

Black aficionados know what he likes by now and that he likes it so much that he’s been recycling it for years. If you were around during the writer/director’s heyday, you’ll remember a precocious and sweary teenage daughter from The Last Boy Scout and both hero and villain plummeting into a swimming pool from a top flight hotel room from Lethal Weapon 2 – but these are good elements, so why not reuse them? Indeed, there may be nothing original about The Nice Guys at all – it’s so familiar, from the seedy Los Angeles milieu of the late ‘70s, to the ecological conspiracy linked to the city’s economy, to the mismatched pair of fuck ups investigating, that it’s tempting to say you’ve already seen it. In fact, you could probably have taken Black’s script and made the film from archive footage alone, but then you wouldn’t have the minor pleasure of watching Ryan Gosling and Russell Crowe enjoy each other’s company. They’re a fun coupling and undoubtedly the best reason to see this perfectly confected genre slab.

But enjoyable though they are, with Black managing the odd zinger – this is Gosling on a myopic witness with Coke bottle glasses, “you put a moustache on a Volkswagen and she’d say, ‘that Omar Sharif sure runs fast’”, it’s not quite funny enough to allay the paedophilic undercurrent (there are a lot of sexualised children in this flick) or the movie’s unreconstructed misogyny. Ah, you say, but it’s a period piece – a grab from a less enlightened and politically correct era, hence those gratuitous breasts in the prologue, but setting the movie in the past doesn’t regress the audience, though it may give them an insight into the filmmaker’s psyche.

So The Nice Guys is a very old fashioned bit of comic neo-noir, with a suitably labyrinthine mystery at its heart, but it needed to be wittier than it is, perhaps adopting a more grounded tone than it does, so that the humour had a chance to stand out rather than being forced, in order to be great rather than diverting. “It’s not the sex, it’s the story,” says Crowe at one point, a scantly clad teen lying on the bed in front of him, but it’s the sex you remember, and some of it feels very grubby indeed. Polanski had dramatic heft to undercut his corruption of innocents, but given what happened later with him and a 13-year-old, not for nothing in the year and city in which Nice Guys is set, that doesn’t necessarily signal moral outrage.