The Big Picture: Final Fantasy: The Spirits Within (PG)

Director Hironobu Sakaguchi starring Ming-na Wen, Alec Baldwin, James Woods 120 mins

Heralded as the greatest advance yet in computer-animated cinema, Final Fantasy: The Spirits Within has also been talked of as the first movie to call time on real-life actors. Why bother indulging spoilt stars and their absurd demands when software can produce such photorealistic human characters? As director-creator Hironobu Sakaguchi argues: "Sometimes, human actors can be very selfish and not listen to the director and producer. But our actors are always willing to work on time and take direction." Viewed from a certain angle, the idea has a distinct appeal: imagine never having to watch Robin Williams on screen again.

On the other hand, while this movie may inaugurate a new era in animated sophistication, its shortcomings suggest that the redundancy of flesh-and-blood performers is still some way off. The graphics of Final Fantasy at times mimic life with eerie authenticity, but the key word there remains "eerie"; what seems at first a minutely accurate rendering of surfaces – flesh, steel, leather – gradually betrays its pixelated origins and maroons itself in a sterile and coldly frictionless atmosphere that seems neither one thing nor the other. However beautiful the replica – and there are some beautiful images littered over its course – the creative finesse sometimes inclines one to wonder not "What's next?", but actually, "What's the point?".

This latter question is especially pertinent in the light of the movie's narrative. Granted, it's based on a Japanese computer game, but why marshal all this groundbreaking technology in the service of such ropy old sci-fi standards? Written by Al Reinert and Jeff Vintar, the plot envisages the kind of rubbly dystopian future familiar from Terminator 2 and Bladerunner, and its borrowings by no means stop there. A meteor has hit planet Earth – the first since, ooh, Evolution six weeks ago – and discharged a vicious strain of alien "phantoms" that suck the life-force out of all that breathes. (That they also resemble giant semi-transparent lobsters is one of the film's lesser technical achievements). Human beings have retreated within barrier cities, but one young biologist, Dr Aki Ross (voiced by Ming-Na), disturbed by apocalyptic dreams, has been scouring the desolate precincts of former cities in search of organic specimens whose "energy signatures" and "compatible spirits" will neutralise the phantom menace. No, I didn't really follow this part either, but you muddle through.

Her theory is endorsed by her colleague and mentor, Dr Sid (Donald Sutherland), and lent practical support by a crack military unit known as the Deep Eyes squadron. Ranged against the forces of righteousness is mad martinet General Hein (James Woods), who seeks a more direct solution to the alien threat, namely, zap 'em all with a big gun. Dr Sid objects to this because it will destroy the Gaia, or earth spirit, and possibly revive the singing career of Pete Seeger to boot.

With so little of this story likely to divert us, our scrutiny is turned upon the characters and how they stack up realistically. The squadron leader, Captain Grey Edwards, is voiced by Alec Baldwin and modelled on the square-jawed ruggedness of Ben Affleck; likewise, his second-in-command, Ryan, is lent gravelly vocal authority by Ving Rhames. It's when one hears something more distinctive in the voice that the tension between real and fake becomes problematic. The obligatory tough chick of the group sounded familiar from the outset, but I couldn't place her for a while – the humorous, throaty drawl seemed to belong to another world entirely. Then I got it – Peri Gilpin – Roz from Frasier! Even more distracting than this is Steve Buscemi's hollow, slightly querulous tone, not a good fit with the handsome, chiselled features of Neil, the group's technical whizz.

This is where you need the inimitable stamp of human peculiarity, because it's the flaws and blemishes that make a character believable, and sometimes loveable. Which brings us to Aki: I'm afraid to say I was fairly smitten by our heroine from the start. Even the knowledge that each of the 60,000 hairs on her head was individually placed by a computer couldn't prevent my admiring the graceful shampoo-ad swing of her shoulder-length bob. Put that together with the mocha eyes, retroussé nose and light sprinkling of freckles, and you have a cross – pardon the swoon – between Bridget Fonda and Jennifer Connelly. For about an hour, I wondered if it could ever work romantically between me and a bunch of pixels, and gradually the fantasy just faded, as fantasies will. Again, it's not perfection one seeks but the smudges of imperfection – the human stain, as it were. Aki is intricately rendered, but her unchanging physical immaculateness begins to cloy, and you tend to wish it was, well, Bridget Fonda or Jennifer Connelly up there.

It takes a little while to sink in, but what the computerised cast of Final Fantasy most signally lack is spontaneity. While it's startling to see the precise facsimile of stubble on a man's chin, or the dilation of a pupil, or beads of sweat on a brow, the characters' faces have a limited range of expression, and their lip movements don't match their speech: everybody tends to talk with the somewhat frozen stiltedness of a stroke victim. This may just be a technical glitch on the animators' road to absolute authenticity, and perhaps the time will come when computers can reproduce every last muscle twitch, every fleeting change on the human dial. But does this accomplishment answer to something a movie audience needs or wants? The film's poor performance at the US box-office last month suggests that, for the moment at any rate, it doesn't.

Then again, it might just be that audiences baulk at the film's combination of ecological piety and stuff they've already seen done better in Aliens, Starship Troopers and Pitch Black. I didn't mind watching Final Fantasy, and certain sequences – the opening search-and-rescue mission, Aki's nightmares – achieve an arresting phantasmagoric creepiness. It's a shame, though, that a film that reaches for the stars on a technical plane can bear to deal in so slapdash and meagre a way with the pleasures of narrative and character.