One of the chief criticisms of James Cameron’s Avatar was that its tale of a soldier going native had been told many times before: it was just Dances with Wolves in space, or Pocahontas with Cirque du Soleil-trained Smurfs. As complaints go, it was an odd one – plots attain classic status for a reason. But it certainly can’t be levelled at this decade-in-the-making sequel, which has almost no plot whatsoever to speak of, original or otherwise.

“The Way of Water has no beginning and no end,” two characters solemnly proclaim at separate points. They’re absolutely right, but then it doesn’t have much of a middle either – or at least the traditional sort, when danger rises and tension and excitement build. Instead, to borrow a favourite Gen-Z phrase, Cameron and Disney have spent a reported $350–$400 million on Hollywood’s first “no thoughts, just vibes” blockbuster; audiences must let the computer-generated Avatar universe wash over them, as our heroes paddle past coral, cavort with plesiosaurs, and gossip with six-flippered whales. The problem is that said universe is unvaryingly garish, which makes watching the film feel like being waterboarded with turquoise cement.

Is it impressive in purely technological terms? Yes. The new, improved 3D makes the characters feel vividly present, helped along by dynamic switches in frame rate (the number of images projected per second) that make the action scenes look as slippery as a 23rd-century video game. But who wants to spend three hours watching a video game? Despite much hand-waving in the script towards weighty themes such as anti-colonialism and environmentalism, it’s hard to recall a film that felt less tethered to the real world. Do you know what would be more evocative of the wonders of nature than a lot of $400 million computer-generated fish? Actual fish.

Without wishing to sound like an Avatar racist, it also doesn’t help that the Na’vi all look so similar, which means the cast’s distinctive screen personas become lost in the pixelly wash. No great loss when it comes to Sam Worthington, the hunt for whose screen persona is about to enter its 23rd year. But Stephen Lang – whose villainous Colonel Quaritch returns, having had his consciousness conveniently transplanted into a Na’vi body – loses all the facial furrows and cruelly gleaming muscles that made the Homo sapiens version of the character so much fun to watch. As for Kate Winslet, even after having seen the film I have no idea who she was playing – the credits said Ronal, but that wasn’t much help.

The story, cooked up by Cameron and a four-person writing team, is a classic piece of franchise-elongation, in which nothing meaningful happens or important changes, and all the pieces are returned to their original positions, ready for the next instalment. And with the first film’s juicier science-fiction conceits now redundant – no one’s hopping between bodies anymore – all that’s left is the ongoing humans-versus-Na’vi feud.