Some sequels are content to simply redo the same movie. Others expand the narrative and introduce new characters. A few decide they want to destroy their own creation and purposely antagonise fans with a movie that bears little resemblance to its predecessor. Joker: Folie á Deux, Todd Phillips' sequel to his smash hit 2019 Joker origin story, does all three. It replays the events of the first film via a court trial. It progresses the story and introduces a love interest for its deranged protagonist. But aside from its sickly colour palette and a setting inspired by the grime of '70s New York, it bears little resemblance to 2019's Joker, chiefly because it's a musical.

Yes, you read that correctly. Not since Gremlins 2: The New Batch has an immediate sequel dared to take such a large swing. And swing Folie á Deux occasionally does, with musical numbers drawing on classic popular songs from the jazz age to the flower power era.

And just like Gremlins 2, Folie á Deux opens with a nod to Looney Tunes with a sequence animated by Sylvain Chomet that serves as a sort of last-time-on-Joker intro. The animation style doesn't look much like a Looney Tunes cartoon though, an early sign that Philips may not be entirely committed to the bit.

Following his rampage in the first film, Arthur Fleck (Joaquin Phoenix) aka "Joker" is incarcerated in Arkham sanitorium while awaiting his trial. He enjoys celebrity status among his guards, who are constantly asking him to tell jokes and requesting his autograph. He has a friendly rapport with Jackie (Brendan Gleeson) a burly Irish guard of the sort you might find in a '30s Warner Bros Jimmy Cagney movie, but Jackie is quick to correct Arthur whenever he crosses a line.

When Arthur joins a prison singing group he attracts the attention of Lee (Lady Gaga), a deranged young arsonist who idolises Joker. The two begin a romance (you might say a "bad romance") that is disrupted when Lee is released. But when Arthur's trial begins, Lee attends every session, her appearance morphing into an alter ego comic book fans will recognise as that of Harley Quinn.

Unable to express their feelings with their own words, Arthur and Lee use the lyrics of classic pop tunes. Sometimes they simply warble in the reality of their everyday situation, while elsewhere we get dream sequences in which the pair imagine themselves as the hosts of a Sonny & Cher-alike TV variety show. The latter are never as elaborate as you might expect, and Philips displays little flair for choreography and staging. Despite Folie á Deux's massive budget (which despite playing out mostly in a few rooms, is 20 times that of Godzilla Minus One!!!), the musical sequences here are no more impressive than the sort of numbers put together by actual '70s variety shows. If you're expecting a courtroom number like the one from Lars von Trier's Dancer in the Dark (a musical that actually pulls off the feat of being gritty and depressing while also toe-tappingly fabulous), you'll be sorely disappointed. Phoenix is no singer, and for the most part Gaga is stifling her talent by playing a woman who isn't exactly a chanteuse, so the vocals of both performers are like nails on chalkboard. There's an inevitable degree of emotion derived from borrowing some of the most moving pop songs ever composed, but it all feels like a case of stolen valour.

Musical fans will find Folie á Deux a slog, but comic book movie fans will likely struggle even more. The elements you might expect of such fare have been purposely stripped away. There's no specific nemesis for Arthur to battle, there's nothing that could be considered an action set-piece, and the violence of the first film is practically non-existent here. The Joker is traditionally known as a criminal mastermind, but that's not what we get here. Arthur is, as his makeup implies, simply a clown, and any threat he may have had in the first movie is nullified by the self-awareness he develops here.

While the first movie may have been heavily derivative of Taxi Driver and The King of Comedy, at least that mashup gave it a secondhand sense of direction. With Folie a Deux, Phillips doesn't settle on mimicking a couple of classics but rather fills his film with bits and pieces reassembled from a variety of sources, from One Flew Over the Cuckoo's Nest to One from the Heart, while the trial plays as a deeply unfunny pastiche of Southern courtroom dramas.

Gremlins 2 was Joe Dante's way of rebelling against Warner Bros and his own success. His sequel upset many fans of the first movie but Gremlins 2 displays a knowledge of and affection for the influences he leans into with that divisive movie. Phillips was quoted early on as being interested in making a Joker sequel, so this isn't a case of a filmmaker trying to get himself out of a contract through cinematic arson. This is a movie Phillips actually wanted to make, so why does it play like it's made by someone who has no interest in either a Joker sequel or a musical?

Directed by: Todd Phillips

Starring: Joaquin Phoenix, Lady Gaga, Zazie Beetz, Brendan Gleeson, Steve Coogan, Catherine Keener