The year’s biggest disappointment has arrived. It emerges with weirdly grownup self-importance from the tulip fever of festival awards season as an upscale spin on an established pop culture brand. Last year we had Luca Guadagnino’s solemn version of Suspiria, and now it’s Joker, from director and co-writer Todd Phillips: a new origin myth for Batman’s most famous supervillain opponent.

Joaquin Phoenix plays Arthur Fleck, a pathetic loser and loner in Gotham City, some time in the early 1980s. Arthur is a former inpatient at a psychiatric facility but is now allowed to live with his elderly mother, Penny (Frances Conroy), in her scuzzy apartment. Poor Arthur has a neurological condition that means he is liable to break into screeching laughter at inopportune moments. He has a crush on his single-mom neighbour Sophie (Zazie Beetz) and pines to be a comedian, hero-worshipping cheesy TV host Murray Franklin (Robert De Niro). But he can only get a job as a clown in grinning makeup and floppy-toed shoes twirling an advertising banner outside a store, where he is bullied and beaten up by young thugs passing by. One day, after the humiliation and despair become too much to bear, Arthur gets hold of a gun and discovers that his talent is not for comedy but violence.

Phillips has already directed a film featuring a brilliant unfunny-funny figure with learning difficulties: Alan in The Hangover, played by Zach Galifianakis, that strange dysfunctional figure who mispronounces the noun “retard”. I wonder what Joker would be like with Galifianakis in the lead. Well, the casting of Phoenix indicates more clearly how sexy Joker is supposed to be.

There is great production design by Mark Friedberg, some tremendous period cityscape images by cinematographer Lawrence Sher, and a strong performance by Phoenix, though not his best – it is not as good as his appearance in Paul Thomas Anderson’s The Master. The film holds your attention up until Joker’s terrible revenge bloodbath on the subway early on, perhaps intended to echo the notorious Bernhard Goetz shooting of 1984 – although Phillips prudently makes it a non-racist attack. After this, the film loses your interest, with tedious and forced material about Joker’s supposed triggering of an anti-capitalist, anti-rich movement with protesters dressing as clowns. Joker’s own criminal and serial-killer career bafflingly fizzles.

The film makes reference to movies from around the drama’s era, such as the Death Wish films, The French Connection and maybe even Star Wars, but it’s more obviously a laborious and pointless homage to the Scorsese/De Niro classic The King of Comedy with a bit of Taxi Driver, which means that at various moments it’s a bit like The King of Comedy and Taxi Driver, only not as good.

The connection is signalled by the casting of De Niro himself, but it is nonetheless unearned and pedantic, especially compared to Lynne Ramsey’s You Were Never Really Here, also starring Phoenix as a loner living with his mom, which managed the connection more adroitly.

The whole idea of the malign clown should be very relevant. We live in an era of trolling, incels and internet bullying. (The grisly Milo Yiannopoulos described himself as a “supervillain” on his now cancelled Twitter bio.) There’s nothing wrong and everything right with engaging with all of this – and the “copycat” row is a red herring. But, perhaps because online aggression is difficult to dramatise, Phillips understandably wanted his film to be set in a pre-web age. Yet he cheats an anachronistic quasi-YouTube moment into his story when a video of Arthur’s catastrophic attempt at standup comedy somehow emerges. (I wonder if there wasn’t an earlier, contemporary-set draft of the script.)

Taxi Driver, only not as good … Joker. Photograph: Warner Bros

This Joker’s genesis is determinedly mature and uncartoony, compared to, say, Jack Nicholson’s low-level crook Jack Napier falling into a chemical vat in Tim Burton’s Batman, turning him into the Joker with white skin, green hair and a rictus grin. (The look of DC’s Joker was originally inspired by Conrad Veidt in the 1928 silent classic The Man Who Laughs, a man whose face was disfigured into a grin by his father’s political enemies.)

There is no reason why Phoenix’s elaborately backstoried Joker shouldn’t be as powerful as Heath Ledger’s mysterious, motiveless, originless Joker in The Dark Knight. But at some stage the comic-book world of supervillaindom has to be entered, and Ledger was more powerful because he wasn’t weighed down with all this realist detail and overblown ironic noir grandeur, and he wasn’t forced to carry an entire story on his own. This Joker has just one act in him: the first act. The film somehow manages to be desperately serious and very shallow.