The first feature from enigmatic singing sensation Sia is an intriguing prospect and, musically at least, it doesn't disappoint, though there are other more glaring issues. Set in a diverse New York neighbourhood, it's the story of a largely nonverbal autistic teen, whose life is thrown into disarray when her grandmother dies and leaves her in the care of her errant, former addict half-sister.

The film stars regular Sia collaborator Maddie Ziegler, who Sia discovered on TV show Dance Moms and who has been starring in her videos since she was 11, beginning with the one for 'Chandelier'. Ziegler plays the eponymous Music, while Kate Hudson is her sister Zu. Music thrives on routine and predictability and struggles with the impact of new stimuli so, when Zu takes charge, her chaotic approach to life instantly creates conflict. Luckily there are helpful neighbours: Leslie Odom Jr's Ghana-born Ebo, who Zu takes a shine to, and Hector Elizondo's George, who she has had run-ins with.

The coming together of contrasting characters and the redemptive arc for Zu feels very familiar. Although Hudson is believably twitchy, she's an odd choice for the role of a long-term addict as, despite attempts to distract us with her shaved head, she's practically glowing, and seems the picture of radiance, fitness and health – the Hollywood Foreign Press Association clearly don't agree, since she's been nominated for a Golden Globe for her efforts. As the focus shifts away from the more unusual character of Music and onto Zu's romantic and drug-dealing drama, it is disappointing. Ziegler is clearly giving it her all in the title role, and her expressiveness does work well in the flights of musical fantasy – yet the casting of a non-autistic actress has been heavily criticised.

When the Tony Award-winning actor Odom (best known for Hamilton, who impressed recently in One Night in Miami…) pops up his character at first seems worryingly close to the much-maligned 'magical negro' archetype – a term popularised by Spike Lee – but he eventually gets some decent screen-time and backstory. Sia herself appears (sans big wig, but wearing a green mud mask), in a slightly cringing cameo.

All three leads get to participate in song and dance numbers, with the songs written by Sia; these act as explosions of vivid colour and energy, as well as joyful, escapist interludes, and are very characteristic of the artist's work. Yet there are a few too many reasons to question Sia's judgement here. An interesting speech on autism from Ebo, which emphasises the special way Music sees the world, is earnestly intentioned but could also be construed as patronising. It's a shame that the film doesn't maintain its focus on and more sensitively develop Music's character, given that autism is so seldom cinematically explored.

Available to watch on demand from Mon 15 Feb.