Directed by Joseph Kosinski. Starring Jeff Bridges, Garrett Hedlund, Bruce Boxleitner, Olivia Wilde, Michael Sheen, James Frain PG cert, gen release, 125 min

Disney's Tron: Legacy, another sequel nobody knew they wanted, is a competent but underwhelming, CGI-saturated sci-fier, writes DONALD CLARKE

THERE ARE any number of reasons not to make a sequel to Tron.

For starters, the 1982 original wasn’t all that much of a hit. Featuring some new technique called computer-generated imagery (it’ll never catch on), the Disney film fought its way to a respectable, but far from stellar, $33 million at the US box-office. If the public really were screaming out for a follow-up then it would, surely, have taken less a quarter of a century to arrive.

Tronalso wasn't terribly good. Following Jeff Bridges's software engineer as he entered a videogame universe, Tronwas, in one unhappy sense, a decade ahead of its time. Not for the last time, punters wondered why so much energy had been invested in the digital effects and so little in the script.

Most significantly, the picture relied on a vanished class of novelty for its appeal. Made (lest we forget), two years before the launch of the Apple Macintosh, a decade before the advent of the PlayStation and more than 20 years before the Wii arrived, Tron did a very good job of rendering a digital environment. Even if the effects had been a quarter as impressive, it would still have seemed like a visual marvel. Nowadays, you can see more impressive images on your telephone.

So, returning to that world is akin to manufacturing a sequel to the Lumière Brothers' 1896 Arrival of a Train at La Ciotat. The train's coming into the station. The train's coming into the station. The train comes into the station for two long hours. Who cares?

All would, however, be forgiven if Tron: Legacyhad something like a decent (or even comprehensible) plot. Such is not the case.

Events begin with Sam Flynn (Garrett Hedlund), son of Kevin Flynn (Bridges), playing a trick on the evil men who now run the company his dad helped create. From the confines of his humble apartment, he frustrates the firm’s latest software release by placing the source code on the internet.

Kevin vanished some years ago, and Sam has turned into a class of morally tormented recluse. Re-engagement occurs during a visit to the video arcade where it all started. After pushing a few of the wrong buttons, he is transported into the parallel universe that is The Grid. As before, computer programmes take on physical form and fleshy humans are regarded as walking deities.

If you’ve ever yawned and clicked your way past the expository scenes in an otherwise enjoyable video game (“Brownclaw has secured the amulet of Marshgas!”) then you will have some idea what to expect from the plot. While Sam’s dad lurks soporifically in a gleaming, cod-Kubrickian shed, a demonic younger version of Kevin/Jeff exacts terror on The Grid’s shiny denizens. The rest is too mundane to bother relating.

Technically, Legacymeets state-of-the-art standards but fails to progress far beyond that. You sense the film is very proud of its achievement in placing a 33-year- old Jeff Bridges among the action, but, sad to relate, the character's awful shininess renders pseudo- Bridges more inhuman than his creators' can possibly have intended. The 3D photography is so passively underwhelming you find yourself constantly checking that your glasses haven't tumbled into the popcorn.

At least Daft Punk, whose soundtrack album has already received decent reviews, manage to do something interesting with their brief. The duo’s canny mash of early-1980s synth pop and contemporary Euro-funk slides from the speakers very winningly.

What we have here is a competently made but largely pointless amalgam of the worst bits from The Matrixwith the silliest bits from The Fifth Element. Elder Bridges ruminates like the droning sages from the former franchise; a jaw-droppingly awful Michael Sheen prances around like a camp spasm from the latter unlovely entity.

All the while, desperate for distraction, punters wonder what unlikely 1980s film will be granted a sequel next year. Will we finally get to see Popeye 2? What about Yentl: The Return? City Heat Reignited?Rule nothing out.