The ever-expanding slate of promised “Avatar” sequels isn’t the only cutting-edge 3-D spectacle that James Cameron fans have been waiting forever to see. The Japanese manga adaptation “Alita: Battle Angel” has also been on the “Titanic” auteur’s to-do list for years, a back-burnered casualty of not-quite-there-yet effects technology and Cameron’s own evolving priorities.
Leave it to director Robert Rodriguez, similarly ambitious (if slightly more expeditiously inclined), to take Cameron’s script and finally will it onto the screen. The “Sin City” and “Spy Kids” DIY specialist gamely harnesses the sprawl of Cameron’s vision, teaming with lead Rosa Salazar (the “Maze Runner” series) to infuse the dystopian proceedings with bright energy. Still, genuine as the pair’s performance-capture cyborg heroine might feel, some of her most pivotal interactions play like exercises in emotion rather than the real thing.
We’ll guess that the film’s setting wasn’t the creative component that kept us on hold, given how derivative it feels: a grungy post-apocalyptic metropolis whose downtrodden citizenry can only dream of finding a way to the elite-inhabited sky city tethered overhead. (“Upscale” is right.) Shades of “Elysium,” among various others. Where Rodriguez and crew make the true impression is in prognosticating the no-biggie prevalence of cybernetic splicing, as seemingly every other character or background face is strikingly tricked out like some sci-fi Swiss Army knife — the future’s answer to contemporary tattoo culture.
Naturally, then, techno-medic Dr. Ido (Christoph Waltz) sees plenty of possibility when he comes across a sad hunk of cyborg detritus in the city scrapyard. (Or maybe it’s some residual affinity from Waltz’s “Big Eyes” turn that makes him paternally fall for the castoff’s oversize peepers.) The doc puts his find back together again, bittersweetly anticipating echoes of someone he’s lost — and unanticipatedly powering up a serious amnesia case and one mean kung-fu fighter.
Alita’s typical-teen searching and rebelling puts together some pieces of her puzzle while tantalizingly turning up others. Like a giggly inversion of the cold AI in “Ex Machina,” she finds a real-live boyfriend in hunky Hugo (Keean Johnson). He turns her on to chaotic (and 3-D-riffic!) Rollerball — er, Motorball. She tangles with cyborg bounty hunters and assassins (Ed Skrein, killing it, along with Jackie Earle Haley); the city’s cool-cat kingpin (Mahershala Ali, cribbing from Laurence Fishburne’s Morpheus, in the “Matrix” movies); and Ido’s enigmatic ex (Jennifer Connelly).
Throughout, Salazar and the filmmakers have us pulling for Alita, and feeling for her, and largely believing in the reality of the character — but more so when the dynamic is solo-and-endearing than tender opposite someone else. For all of Alita’s she-Pinocchio charm — and her Cameronian estrogen-charged badass-itude — she can’t quite carry the audience all the way across that pesky uncanny valley.
ALITA: BATTLE ANGEL
Directed by Robert Rodriguez. Written by James Cameron and Laeta Kalogridis, based on the manga series “Gunnm,” by Yukito Kishiro. Starring Rosa Salazar, Christoph Waltz, Mahershala Ali, Jennifer Connelly. At Boston theaters, suburbs, Jordan’s IMAX in Reading and Natick. 122 minutes. PG-13 (sequences of sci-fi violence and action, some language).Tom Russo can be reached at email@example.com.