In Christopher Nolan’s time-bending, mind-boggling blockbuster the director is in playful mood, peppering the script with sly messages to the audience. “Don’t try and understand it,” says one character early in the film. “I don’t understand it,” says another later, “it’s backwards.”

“Does your head hurt yet? asks Neil (Robert Pattinson) after some indigestible explanation of events. “Yes,” replies the Protagonist (John David Washington) and most of the befuddled audience. In other words, don’t bother trying to keep up with Tenet’s plot. Just buckle up and enjoy the thrilling ride.

In fact, the whole plot could be one big McGuffin, one of Hitchcock’s fabricated but meaningless props to get from A to B. Where is Nolan taking us? He is playing with the concept of time and the outer limits of what cinema can conjure for its audience. “James Bond on acid,” as someone has described Tenet, is only half-right. Its’ muted colour palette and corporate mood is the opposite of psychedelic. But the spirit of Disney’s sorcerer’s apprentice is evident in the fun Nolan has opening his Pandora’s box of technical tricks.

In an opening sequence that will delight those who are tone-deaf to classical music a gang of masked terrorists attack Kiev National Opera House and smash up the orchestra’s instruments. They fight a running battle with guards, who include our unnamed Protagonist. He is caught and tortured before swallowing an odd-looking round metal pill.

Waking up on a ship off the coast of Oslo, he is told by his handlers (who include Pattinson) that he is now working for a secret organisation called ‘Tenet’, whose mission is to save the world from “something worse” than a nuclear holocaust. Like Bond, the Protagonist is shown futuristic gadgets and whisked around the world, from Talinn to Vietnam and Mumbai, via Italy’s Amalfi coast. He bungee jumps off skyscrapers, has some brutally exciting fights and is involved in magnificent car chases.

There’s also a statuesque blonde (Elizabeth Debicki from The Night Manager) and a dastardly villain, the Ukrainian Sator (Kenneth Branagh), who describes matter-of-factly what his men are going to do with the Protagonist’s balls: “It’s very gratifying to watch a man you don’t like try to pull his own balls out of his throat before he chokes.” Branagh is electrifying here, playing against type; any ‘luvvie’-ness has gone the same way the afore-mentioned testicles. Imagine what Charlie Brooker will look when he delivers his verdict on 2020 at the end of the year: that’s how intense and angry Branagh is here.

There’s plenty to enjoy and admire in Tenet. The wonderful John David Washington is still “as fresh as a daisy” here after his breakthrough performance in BlacKkKlansman. ‘Dressed’ by Michael Caine’s city gent, he looks effortlessly cool in a posh suit. But even Washington’s deadpan delivery of some long-winded explanatory dialogue (there’s quite a lot of this in Tenet) can’t quite stop us scratching our heads or yawning. The film does go on a bit; two hours would have been enough and the repetitious tedium of the massed battle at the end felt like watching Attack of the Clones.

For brainy puzzle-solvers, there is an algorithm, temporal inversions galore and the ‘grandfather paradox’ to keep your brain ticking like the clock in Dunkirk. If you pay attention Ludwig Göransson’s Zimmer-like score even contains reminders of those mythical ‘backwards’ messages alleged to be hidden in the run-out grooves of vinyl albums back in the late 60s/early 70s.

Or am I just reading too much into it?