Five years ago, Todd Phillips released his much-acclaimed take on the DC Comics supervillain, Joker, with Joaquin Phoenix wearing the clown makeup as the bananas Pagliacci Arthur Fleck in an odd pastiche Scorsese thriller with Joker as both Travis Bickle and Rupert Pupkin – and granted the unearned honour of killing a character played by Robert De Niro. I found it bizarrely overpraised and overrated by saucer-eyed pundits, but it became a prize-winning sensation – and perpetuated the awards-season tradition of rewarding the idea of comedy on the strict understanding that it’s not supposed to be funny. Now the sequel is here, and though it ends up as strident, laborious and often flat-out tedious as the first film, there’s an improvement. It’s a musical, of sorts, with Phoenix and others warbling show tune standards, often in fantasy set pieces, a little in the way of Dennis Potter’s Pennies from Heaven. This gives it structure and flavour that the first film didn’t have. And that sensational acting and musical talent Lady Gaga is now in the mix – though with nothing like the humanity and depth she had in Bradley Cooper’s A Star Is Born – as Harleen Quinzel (that is, Harley Quinn) a deeply disturbed psychiatric patient who meets Joker in the music therapy class that he is allowed to attend as reward for good behaviour while on remand waiting to stand trial for his five murders. They fall deeply in love – with each other, that is, adding to the existing self-adoration of each, although it is never clear whether the leads’ narcissism is intentional. No doubt about it, – the opening is sensational. A spoof Warner Bros Looney Tunes cartoon reprises the story so far, raising the curtain for a barnstorming first section showing Arthur’s prison existence. There’s a great supporting cast, with Brendan Gleeson as the prison guard (weirdly, it is only Gleeson whose character tells a joke while giving some indication of what one sounds like), Catherine Keener is Arthur’s lawyer, Steve Coogan is a tabloid TV interviewer and Zazie Beetz briefly reprises her role as Arthur’s former neighbour. There’s a real spark when Joker and Harley meet-uncute in the joint. But the whole movie finally turns out to be oppressively, claustrophobically and repetitively becalmed in that oddly unreal Gotham-universe jail with Phoenix and Gaga kept apart for long periods – and Phoenix’s own performance is as single-note as before, though certainly as forceful and his screen presence is potent. The gameplan of defence lawyer Maryanne Stewart (Keener) is to convince the judge that her client was psychologically disturbed by his abusive upbringing and that he deserves hospital treatment on the grounds of diminished responsibility. District attorney Harvey Dent (Harry Lawtey) says Arthur is not mad and deserves the electric chair. As for Arthur, he is conflicted. He understands that the insanity plea is his only chance. But he also longs to embrace his Joker destiny again – to embrace the crazy scary-clown persona that his lawyer tells him to reject: it has given him celebrity status and a heroic destiny and it has brought him love with Harley. Lady Gaga brings a sly and manipulative malice to her role: Harley is secretive, smart and genuinely disturbed in a way that Arthur/Joker perhaps isn’t. Is she to be the Lady Macbeth of DC supervillainy? Sort of. The story as constructed doesn’t give her character much of a chance at development – in that direction or any other. And it is possible to feel very restless during the final section and wonder whether anything remotely plausible, sad, funny or unexpected will be revealed about Arthur, given that the film’s body language insists on its mythic importance. This crazy self-possession propels the film up its laborious narrative gradient. And Lady Gaga delivers a diva charge. Could it be that her Harley Quinn will return in an adventure of her own?