Directed by Christopher Nolan. Starring Leonardo DiCaprio, Ken Watanabe, Joseph Gordon-Levitt, Marion Cotillard, Ellen Page, Tom Hardy, Cillian Murphy, Michael Caine, Tom Berenger 12A cert, gen release, 148 min

IT WOULD be easy to get distracted by the hype swelling around Christopher Nolan's breathtakingly grandiose – Is it baroque? Is it gothic? Is it lobster? – follow-up to the head-spinningly successful The Dark Knight.

In one sense, however, the hopeful hysteria is utterly justified. Inceptionmay be a tad pretentious, somewhat intellectually shallow and riddled with narrative wormholes. But, in a summer groaning with weightless pabulum, Nolan's efforts to introduce artistic roughage to the July blockbuster deserve enthusiastic gratitude. The fact that every second 17-year-old guy will think Inceptionis the greatest film ever made should not be held against it.

A proper explanation of the plot would require an overhead projector, a stack of handouts and a small jug of strong hallucinogens, but we’ll try. Leonardo DiCaprio plays a grey presence named Cobb who works as an “extractor”: for a fee he will invade the dreams of a subject and obtain information from their psyche. Working with a team of specialists, he designs intricate imagined worlds and, after inviting the dozing mark within, uses his knowledge of the architecture to manipulate and exploit.

Following one particularly noisy mission, Cobb is invited to take the process to another level. Rather than withdraw memories from an individual, he might, perhaps, like to place an idea within a target psyche. Sinister Ken Watanabe suggests that Cobb get sleek industrialist Cillian Murphy to make some sort of decision concerning his business.

There is, however, a problem. Cobb’s late wife (an elegantly distraught Marion Cotillard) keeps turning up in his subconscious and disrupting the carefully laid plans.

Do you have any questions? Don’t worry. Ellen Page, playing an architecture student inducted into Cobb’s gang, is on hand to ask them for you. All of them. Every last one. Barely a minute goes by without Cobb stopping to explain the absurdly precise and arcane mechanics of this fantastic imagined world. If you die in a dream you wake up. If you die in a coma you get sent to a kind of chaotic limbo. This is one of those rare films that incorporates it own FAQ sheet into the dialogue.

Nolan appears to be striving for a James Bond film as written by Jorge Luis Borges. (Indeed, the director has acknowledged that the lengthy arctic sequence is an homage to On Her Majesty's Secret Service.) For long passages of this hugely entertaining, hugely huge film he succeeds impressively. As dreams within dreams give way to dreams within dreams within dreams, the task of ordering the narratives offers the viewer an increasingly delicious challenge.

Meanwhile, remembering that the picture also has a duty to fire the adrenaline, the director devises a series of action sequences – slick and cool enough for Michael Mann – that trip over one another to shake the fillings from your molars.

Yet for all the gorgeously autumnal set design, stirringly Wagnerian music and consistently strong supporting performances, Inception's desperate need to be taken seriously becomes, as events progress to a an overly neat denouement, a little wearing.

On the one hand, Nolan appears keen to have us ask ourselves Bishop Berkeley’s question concerning the uncertainty of reality. On the other, acknowledging Page’s incessant questions, it wastes pages of dialogue explaining an alternate universe as mundanely functional as an electric lawnmower. The harder you ponder the film’s efforts to engage with the unreliability of consciousness, the thinner and less worthwhile those experiments seem.

None of which matters all that much. When Inceptiongrabs you by the lapels and wrestles you into submission, you probably won't care that it has a pretentious paperback stuffed conspicuously into its jacket pocket. Mainstream cinema needs the likes of Christopher Nolan. DONALD CLARKE