Christopher Nolan has form when it comes to films about wilful self-deception and the unreliability of our own minds – Memento (2000) was a striking account of an amnesiac using polaroids, tattoos and notes-to-self to hunt down his wife’s killer. With Inception he turns his protagonists’ minds loose in the world of dreams, a shifting labyrinth in which he builds a movie at once structurally and psychologically complex and edge-of-your seat thrilling.

Cobb (Leonardo Di Caprio) is a corporate thief with a very particular skill set: he can break into dreams and steal the dreamers’ secrets. But when one of these burglaries goes wrong, he finds himself hired to pull off the ultimate job – not stealing an idea, but this time implanting one. Far more dangerous and ambitious an operation, this involves convincing the victim’s subconscious that the idea is his own, and so Cobb must bury it at the bottom of a dream within a dream within a dream and disguise it with all manner of feints, doublethink and trickery.

At base, Inception is a standard heist movie: a team is formed, all with unique talents, and off they go, blowing stuff up, chasing around in cars and shooting people, all in the service of a plot ostensibly about helping a shady foreign businessman get at the heir to a banking fortune. But while there’s some great individual fisticuffs-and-fireworks scenes, why this works so brilliantly as an action movie is that these dramas are all playing out simultaneously on different dream levels; and as you move down these levels, time speeds up. This means that weeks can unfold in one reality as a van falls off a bridge in another, which creates a relentless piling up of tension and acceleration.

Because all this is happening inside people’s heads there is also built-in psychological depth, although the only character who is fully formed and complex is Cobb; apart from the banking heir’s off-the-peg father issues, most of the cast are bit-players and comedy foils. This may be deliberate – who knows what layer of whose dream some sequel down the line will show us to have been in all this time, and who the real dreamweaver is (though it’s hinted that ‘Ariadne’, who designs the dreams’ physical spaces, knows more than she’s letting on). Anyway, the psychological plot that underlies the action is that Cobb has lost his wife and kids and they keep invading his – and so everyone else’s – dreams and causing trouble; he must deal with his issues before ‘inception’ can be realised and the dream worlds escaped.

And then there’s the 3D-puzzle element, the interlocking stories that must be resolved. Some might find Inception too obviously contrived; the intricate plotting means you’re constantly aware of Nolan as the ultimate dream-maker, although the fact that there’s an intelligent being behind a Hollywood blockbuster is a sufficiently rare and wonderful thing as to be almost worth drawing attention to. This isn’t a film that you can let wash over you – you have to throw yourself into it, and this active involvement in figuring out what’s really going on makes for an absorbing experience that rushes past far faster than the 148-minute running time would suggest. It is the dreamworld setting that makes solving this puzzle seem so urgent, because we can believe in the precariousness of the dreaming mind: while we might be able to imagine the Matrix, or amnesia, we’ve all actually experienced the vulnerability of sleep, the realness of a dream, and those nightmares you see for what they are but still can’t wake up from.

Visually, Nolan captures the mutability and fragility of dreams while refraining from the kooky psychedelia that so often decks out filmmakers’ lands of the imagination. He has to, because the point here is the struggle to determine what is real; and so his dream worlds are like the real one, except with mazes and paradoxes (like Escher's famous infinitely-looped staircase) so that they fit inside the dreamer’s head. The supporting characters are mostly winning, if faintly cartoonish, and DiCaprio is well cast as Cobb, his man-boy appearance fitting the notion of someone lost between the different levels of his own psyche. The only really jarring note – apart from some odd lost plot strands which will presumably be picked up again in a sequel – is Ariadne, an architecture student blessed with preternatural intelligence and self-assurance, and yet accepted unquestioningly by the rest of the team.

The final twist is surprisingly simple and controlled, a sudden deflation of the explosive tension and complexity; it’s like emerging from a dream, and yet it merely deepens the mystery. Never have I left a cinema after two-and-a-half hours so desperately wishing I could turn round, go straight back in, and watch the sequel.