Passion projects that have long been housed in development hell rarely inspire much confidence, but when it’s an enterprise from James ‘never-tell-me-the-odds’ Cameron, the journey to the promised lands seems a little more worthwhile.

However, having stepped away from the director’s chair to focus on Avatar 12 (or something), in stepped Robert Rodriguez—­the renowned brains behind Desperado and Spy Kids 3-D: Game Over, and everything in between. The finished product is a smooth and functional visual spectacle, but one whose moments of awe are frustratingly bogged down in YA treacle.

Based the 90s manga Gunnm, this American live-action adaptation charts the heroic self-discovery of Alita (Rosa Salazar), a cyborg who has lost her memory. Damaged in an interplanetary war known as The Fall some 300 years earlier, the disembodied Alita is found in a scrap heap by Dr. Ido (Christoph Waltz), who fixes her up with a new mechanical body and a roof over her head.

‘Home’ here is the Iron City—­a wretched hive of scum and machinery—­which lies symbolically below the lavish, semi-floating paradise of Valem. Access to the upper city is earned through either winning the grand prize in Motorball (think basketball-meets-rollerblading-meets-Gladiator) or more nefarious means: doing dirty jobs for Vector (Mahershala Ali), an ex-resident of Valem now calling the shots in the Iron City’s criminal underbelly.

Alita fancies her chances at the former, and is introduced to Motorball at a street-level by Hugo (Keean Johnson), the painfully dull (but cutesy!) boy-next-door. The two are instantly infatuated with one another, and Alita’s subsequent journey of self-discovery relies heavily on this blossoming relationship—much to the film’s detriment.

For those that like their IMAX 3D nauseating with a side of spatial confusion, Alita: Battle Angel may disappoint; the action set-pieces are well-oiled, with spectacle engineered for safe comprehension over maximalist frenzy (à la Marvel.) But fear not—for the budding teen romance that insists on pinning this all together will make sure that stomachs are well and truly churned.

“Does it bother you? That I’m not completely human?” Alita asks Hugo, who responds, “You are the most human person I have ever met”. Besides boasting some truly impressive emetic qualities, the moment also encapsulates the fundamental misstep taken in this particular telling of Alita: tethering the (re)formation of her self-identity to someone else. That this someone else had the misfortune of being played by Johnson undoubtedly factors into such botchery, but the narrative failure runs deeper still.

As far as live-action manga adaptations go, Alita is largely competent in avoiding the pitfalls of its recent precursors; there’s no ScarJo or Nat Wolff to be found here. Perhaps its most impressive feat is in its handling of the big set-pieces, owed in large part to a dynamic but clear direction from an assured Rodriguez. Straightforward bar fights are devised ambitiously, while the scintillating Motorball finale watches less like Podracing as it does the chariot sequence from Ben-Hur (no, really.)

Mahershala Ali’s casting raised a few eyebrows, and he could easily have turned up for his pay-check and ran. Thankfully, he seems to be the only actor here who properly owns the material, or even wants to—Ali knows the story is trite, but insists on giving us some top-tier pantomime bastardry nonetheless (“You shoulda known… no one is greater than the game.”)

The same cannot be said for the rest of the supporting cast. Waltz continues his perplexing barren run in playing slightly-offbeat scientists (who hurt you, Christoph?), while Ed Skrein’s cyborg bounty hunter comes off as irritating as his ridiculous appearance would suggest. Jennifer Connelly hints at a promising arc (and serves some serious looks while doing so), but is disappointingly side-lined until the deus ex machina requires her.

For all its faults, the achievements in world-building and potential mythology do raise hopes for a sequel. Ali’s Vector comments that he would rather rule in the hell of the Iron City than serve in Valem’s heaven, and the prospect of seeing the latter of this societal binary is an exciting one (if also another ill-judged omission from the film as an individual piece).

Yet, all this is tarnished in the film’s final moments, a conclusion almost insulting in its self-satisfaction. An angel falls and a warrior rises—but at what cost?

Dir: Robert Rodriguez

Scr: James Cameron, Laeta Kalogridis

Cast: Rosa Salazar, Christoph Waltz, Mahershala Ali, Jennifer Connelly, Keean Johnson, Ed Skrein

Prod: James Cameron, Jon Landau

DOP: Bill Pope

Music: Tom Holkenborg

Country: USA

Year: 2019

Runtime: 122 minutes

Alita: Battle Angel is out in UK cinemas from February 6th.