There's really no way around it: TRON: Legacy is almost certainly the shallowest film of 2010. It is huge and shiny; it sounds like God himself was tinkering in the editing booth; the female lead is about as hot as it gets, and she spends every minute in a form-fitting costume with brightly colored lines in all the right places. It is in possession of a third act that seems almost proud of all the sense that it doesn't make, and the whole thing is anyway a nostalgic cash-in sequel to a movie that flopped 28 years ago, which even viewed now has little to recommend it beyond the charm of how phenomenally lousy the bleeding edge of CGI used to look.

But, not incidentally, TRON: Legacy is a hoot. A gaudy, disreputable, empty-calorie present for the holidays that makes last year's Avatar look like the noblest work of cinematic storytelling in a generation, but it shares that groundbreaking film's most admirable achievement, that of being wholly immersive, especially if you see it in the full-on IMAX 3-D treatment that is, honestly, is the only reason to bother (and given what a weighty percentage, relatively speaking, of its opening weekend box-office was from IMAX engagements, it would seem that a large chunk of American moviegoers would agree with me). For all of its disastrous script problems, and despite a first-time feature director, Joseph Kosinski, culled from the world of video game advertisements - and how telling is that? - whose approach to the material is ludicrously glossy without any sort of dramatic grounding, TRON: Legacy presents a visually luxuriant world that is mostly without precedent; though it cribs some details from the original TRON, rightfully so, the new film plays less as a continuation of its predecessor's mise en scène and more as a reinterpretation of the same material given a whole new bleeding edge of technology.

In a cockeyed way, this makes Legacy the best possible sequel to TRON: not because of how it does or does not expand upon that film's characters and narrative possibilities, but because of the way that it recaptures the spirit of the original. TRON existed almost solely to show off fancy-ass technology at its most dazzling and never-before-seen, while also throwing a bone to the audience's brains in the form of a fun Jeff Bridges performance; this is precisely the same justification for its sequel. The most advanced world-building CGI and 3-D effects in history (the cameras used to shoot Legacy are a generation more advanced than the Avatar cameras), Bridges playing a version of the Dude from The Big Lebowski, and very little else: but there is a legitimate human need for gargantuan spectacle, and this is something Legacy provides in spades.

Like its predecessor, Legacy is mostly the story of a young man stuck inside a computer-generated reality. In this case, it's Sam Flynn (Garrett Hedlund), the 27-year-old son of Kevin Flynn (Bridges), who has become something of a disaffected angry loner in the many years since his dad went missing, leaving the multinational software/video game company Encom in disarray. As things stand, Endcom has become a joyless Microsoft clone, but Kevin's single remaining ally on the board of directors, Alan Bradley (Bruce Boxleitner), cares enough for the company and the family's legacy to give Sam a lead on a mysterious page he received from Kevin's old phone at a long-defunct arcade. There, Sam discovers that his father was working on a massively ambitious plan to create a symbolically physical manifestation of a computer network which human users could enter, interacting with programs who take anthropomorphic form. This explains where Kevin has been all these years, and a few unlucky keystrokes send Sam spinning into the same digital purgatory where his father has been trapped.

That pretty much does it for the plot of TRON: Legacy, although the four writers credited for getting it onscreen (more people were doubtlessly involved) don't seem to realise this, and persist in adding details about Clu, the program designed by Kevin Flynn to be his permanent double in the network, who has turned the grid into a dictatorship where he rules as, basically, Hitler; there's also some business involving "isomorphic algorithms", self-writing programs that are apparently going to be able to redefine humanity's own existence, though how exactly this is supposed to work is not clear. Along with pretty much everything else that doesn't boil down to: Sam Flynn is trying to avoid being killed by this thing over here, and there is a setpiece in which he does so. Or Olivia Wilde in a luminescent catsuit.

The script is peppered with holes and pointless business, and generally the more you think about things, the less sense it makes (Why does Kevin have to eat, and why does he age, if he's a digital representation of his own physical form? What are the "isos" supposed to imply for flesh-and-blood humans? If Tron himself was such a bad-ass in TRON, how come he's such a wimp now? Do any of the scenes in the last 15 minutes actually conform to what we know about the "reality" of the grid? Why is Michael Sheen playing David Bowie?), but all of this anyway takes a back seat to the totality of the film's design, both visal and auditory: when the lightcycles from the first film come back, in all the best CGI that 170 million 2010 dollars can buy, and sucking up every inch of the IMAX frame, all is right with the world. Everything we need to know about the gladiatorial duel going on before our eyes is encoded in the colors of the objects, how they move, where the cuts happen, what sound cues play out.

Hell, it doesn't even taking "knowing about the duel" to appreciate the happenings onscreen: like TRON before it, Legacy is perhaps best-appreciated solely as a mixture of shapes and colors, stretching deep into the canvass of the screen, an abstraction of steely "high-tech" neons set to the pulsing rhythm of an outstanding score by French electronica duo Daft Punk: snatching elements from Phillip Glass's work, from Wendy Carlos's synthesised soundtrack to the original movie, from the Romantic-influence movie composers of the '40s, and just as a cherry, grabbing the foghorn blares that were so prominent in Hans Zimmer's Inception score, and then coating it all in a veneer of digital manipulation - it's the perfect music for the inside of a computer, heavy and rich, then light and playful, and always perfectly keyed to the visuals. When we want to be stunned by the high-action setpieces, the music settles into a mostly tuneless noodling, just there to keep the heart beating; when the action stops and the draggier parts of the plot start in, that's when the particularly inventive and questing music starts up, to keep our minds occupied by something since the endless minutes of Bridges and Hedlund talking aren't going to do it. In a year of great film music, this is one of the best scores I've heard, musically interesting on its own (though it's not at all like the hook-heavy dance music Daft Punk is best known for), and the best imaginable complement to the visuals.

Though as I think about it more and more, I wonder if that might be better the other way 'round: the visuals are the best complement to the sounds. Because from its music on down, Legacy is one of the best-sounding movies of 2010. A weird claim, but the sheer cacophony of digital sound effects falls incredibly pleasant on the ear; while the film's best gag comes from a cameo by the Eurythmic's "Sweet Dreams" mixed to cunning perfection.

It's all such a rapturous, body-encompassing sensory experience that the sheer pointlessness of the story, right down to the climax that pilfers from The Matrix and then has the gall to count on our having seen The Matrix just so that this film doesn't have to explain what the fuck just happened, is rather easy to ignore, though it hurts that only about a half of the film (certainly not more than that) fits into this explosion of experiential joy: the sequence before Sam enters the system is so much expository tedium (though the first shot uses 3-D to tease us for the spectacle to come, in the finest tradition of pornographers throughout history), and there are a lot of stop and talk scenes in the middle, as though the TRON universe were so interesting for its meta-narrative implications that we all wouldn't rather watch a 40-minute version of the same film consisting of nothing but lightcycle races. And even then, some of the vaunted special effects don't hold together - the de-aging effect used to turn Jeff Bridges into Clu, precisely the same effect used to such success in The Curious Case of Benjamin Button, ranges from perfectly acceptable to incredibly bad, and only ascends to "totally convincing" in but one or two isolated shots, for example. Still, the parts that work couldn't be any better than they are: and they're stunning enough in all their garish glory that as much as I know that TRON: Legacy really doesn't work, I simply don't care.