Dexter Fletcher was the guy who was called in to finish Bohemian Rhapsody after the credited director Bryan Singer was fired. If anyone was wondering just how much of Rhapsody was Fletcher's, they can now compare it to Rocketman, the filmmaker's second rock biopic in a year. In the end, however, I couldn't find any unique directorial imprint in either film.

Rocketman, which recounts Elton John's life from his late '50s childhood through his mid-'70s excess to his early '90s sobriety, is not a traditional pop biopic like Rhapsody or Walk the Line but a self-proclaimed "fantasy", employing John's songs as in a musical. In fact it's much closer to older rock movies like Tommy, Pink Floyd: The Wall, and Julie Taymor's Beatles-inspired Across the Universe. Thankfully, Rocketman eschews the hallucinatory frills that made those pictures practically unwatchable to anyone who wasn't under the influence.

That said, Rocketman's musical numbers – which ignore any sort of real-world chronology – don't add much here. The film is more successful when the songs are simply performed realistically – that is, with John in the recording studio or onstage. The imaginary numbers set in drab London houses or at Hollywood parties feel awkwardly shoehorned in, especially since the film abandons the gimmick for long stretches of its runtime.

As Elton John, Welsh actor Taron Egerton is, fittingly, the movie's MVP. His work is earnest and frankly delightful. (And it's his own singing voice we hear.) Like Rami Malek in Rhapsody, Egerton is your main reason to see Rocketman. While Fletcher's direction is serviceable, the screenplay, by Lee Hall (Billy Elliot), is a lemon, with cliched characters and dialogue galore. It's better than Anthony McCarten's facts-be-damned Bohemian Rhapsody script, but only just.

I laud the decision by John and his husband David Furnish, who coproduced Rocketman together, to make an R-rated, warts-and-all biography. But with Egerton, as John, narrating his life from the confines of a rehab clinic, Rocketman is basically just another therapy movie, with John blaming mean mummy and distant daddy for all the hangups that poor little Reggie Dwight carried with him into superstardom. Ho hum.

The film is at its best when it focuses on John's longstanding collaboration with lyricist Bernie Taupin, winsomely played by Jamie Bell. Their friendship clearly means a great deal to Elton John the producer, so the scenes between the two characters are consistently honest and poignant. Rocketman posits that Taupin is the (platonic) love of John's life, and I believe it.