Yesterday, I escaped from the summer heat into an airconditioned warren in a nearby suburb, its carpeted passages lined with chambers in which people clutched totemically decorated buckets of Coke and tried to link their senses to those of exotic alter egos with the aid of pairs of black-rimmed glasses. My aim was to find out what counts as a quintessential science-fiction blockbuster at the end of the first decade of the twenty-first century. The answer turned out to be an eye-popping exercise in photorealist animation that brings to life a whimsical fantasy world, in the service of a very uninspiring fairy tale.

Some reviewers have noted echoes of the works of Poul Anderson in Avatar, and I’m sure there were also traces of Anne McCaffrey and a hint of Ursula LeGuin. But on reflection, what it really felt like to me was a fourth movie in the Shrek franchise, pipping the yet-to-be-released Shrek Forever After to extrapolate that series’ twin curves of rising technical achievement and plumetting wit to their logical endpoint: a near-immaculate feat of visualisation, accompanied by a staggeringly awful plot in which clunky genre conventions triumph completely over plausibility and originality. Avatar even boasts its very own love story where societal expectations and superficial barriers of size and pastelicity are overcome by generous helpings of pixie dust.

Avatar (which I saw in the 3D version) is certainly an impressive technical achievement, with animation, performance capture and visual effects that blend seamlessly and convincingly for 99% of the time to immerse the viewer in a sumptuously detailed alien landscape. If the handful of exceptions stand out, I suppose that’s just the price of near-perfection: once the eye gets used to being fooled so well, it only takes a minor glitch in depth cues or shading to make you feel that you’re looking at live actors moving in front of a projected background (even when the reality is likely to be something else entirely). There is also the unfortunate fact that although the tall blue aliens known as Na’vi look modestly exotic when they’re interacting with humans, their anatomy is so close to human that sometimes the technology seems to be creating nothing more than a perfect simulation of what actors with slightly different builds, blue body paint and some minor latex prostheses would look like. But mostly, the accomplishments of the visual designers and the army of technicians who’ve brought their conception to the screen appear pixel-perfect, and hit the spot where the brain says “yes, this is real”. The flora and fauna of Pandora are convincingly organic to an Earthly eye — whatever your inner exobiologist is telling you about their plausibility — and on the same gut level the only real flaw in the preposterously humanlike Na’vi is their preposterously perfect teeth.

The staging of the action scenes is breathtakingly good, complex and fast-paced without ever becoming confusing. The aerial encounters are fluid and balletic, making perfect use of the freedom of the technology without devolving into gimmicks. So, there is a lot to enjoy and appreciate as sheer spectacle.

But the script, if not really all that Shrek-ish, is more like Disney’s Pocahontas and Lion King thrown into a blender with Verhoeven’s Starship Troopers and something swept off the floor from one of the Star Trek franchises. The science is hokum, the level of human technology is wildly inconsistent, and the characters make life-and-death decisions for no good reason but the plot arc. And for all of the depictions of warfare and massacres, all of the formulaic gestures of risk and self-sacrifice, there wasn’t a single moment here that moved me half as much as the drowning scene in The Abyss.

If you want an emotionally satisfying fantasy about wounded nature, try Princess Mononoke; if you want a whimsical, visually stunning action adventure where the dialogue rises above “Outstanding, Marine!”, rent the Pirates of the Caribbean trilogy. Sometime in the next twenty years or so, the technology that enabled Avatar will become cheap enough to risk employing alongside a moderately intelligent script. But if you want to see the technical state of the art right now, go ahead and pay your share of Avatar's nine-figure budget. Think of it less as a piece of entertainment than a glimpse of the kind of day-dreams your not-too-distant descendants might well be scripting and directing in real time themselves.