What is Inception? Well. It’s a special-effects movie; a summer blockbuster; a heist flick; espionage thriller, but at its very core it is a tragic love story with vague, albeit familiar, echoes of DiCaprio’s other cinematic outing this year, Shutter Island.

Both films play with – and distort – the “reality” of each scenario and feature haunted heroes trapped by overwhelming feelings of guilt which they try to repress. Inception and Shutter Island are gothic films set in the realms of the unreal, where the femme fatales surface from the subconscious to wreck havoc.

Christopher Nolan may have made the most complex and thrilling blockbuster since The Matrix. He’s currently being touted as the next Kubrick, but that doesn’t add up. Kubrick was an iconoclast. Nolan is more a mainstream variant of an Alain Resnais-like director obsessed with cine-experiments on identity, time and memory. Let’s call Inception, “Last Year in Marienbad meets Heat”.

DiCaprio’s character, Dom Cobb, is a man so troubled he cannot tell what is real and what is not – much like Teddy Daniels. There’s the vague suspicion Inception is one great con and nothing more than a glimpse into a man’s dream world from start to end. Nolan and his DP Wally Pfister make no distinction between the perceived realities of the everyday and dreamtime. The astonishing special effects kick in, but there are some very subtle moments too.

There are clues through out the film in which Nolan could be saying, ‘look closely, look closer. It’s all in the head of Cobb’. Sharp eyes might notice architectural and interior design preferences emerge in supposedly different locales and time frames. One moment we are watching a simple scene of Dom describing to Ellen Page’s dream designer their plans only for Dom to inform his new protégé that they are dreaming. What happens next is truly jaw-dropping as the city around them explodes, expands and folds over. The layers of reality are constantly in question and can be manipulated.

Opening with Hans Zimmer’s droning score, Inception, is ominous and mysterious from the get-go. It’s a fast-paced movie – perhaps too fast – but there’s a lot going on. A Hollywood summer blockbuster that engages the audience on an intellectual and emotional level should not be sniffed at.

Although Nolan enjoys flitting between time-frames and locales (very dreamlike) there is a clear narrative trajectory. The grandiosity does ignore the average dream cycle – ninety minutes – and spreads the film up two and a half hours. Yet every moment is compelling and exciting.

Dom Cobb is the world’s best extractor. When a recent job goes wrong, he’s offered a chance of redemption by a Japanese businessman (Ken Wanatabe) to plant an idea inside the head of a rival (Cillian Murphy) in order for him to dismantle his empire and cede control. That’s the heist part.

The major problem Cobb faces is his own subconscious and the appearance of Mal (Marion Cotillard). She’s dead and been dead for some time, but turns up in Cobb’s dreams and jobs, botching them out of spite. Cotillard plays her character as part vengeance seeking fury and part Ophelia.

We soon learn that Cobb believes he’s responsible for her death, and it would be terribly remiss to further explore that avenue without ruining things. Inception, upon first viewing, is likely to completely knock you for six.

Nolan, like his character, can dream big. There are a handful of scenes that will have you open-mouthed with wonder. Other moments are positively surreal. Wrapping it around an action film could have been too silly, but he makes it work.

For example, the fight scene between Joseph Gordon-Levitt and a gunman in a corridor that is losing gravity is astonishing. But what is more astonishing is the aftermath in which Arthur (Gordon-Levitt) floats down a corridor with the entire cast strapped together one on top of the other as if he’s a hospital porter taking his charge somewhere.

Despite its glorious points there are some inevitable weaknesses. There is too much ‘complex ideas for dummies’ style dialogue and Nolan isn’t quite brave enough to be too ambiguous. The ending is also less effective than it could be. It offers a tingle instead of a jolt.

Packed with inventive action, high drama, ideas and emotion, Inception is Nolan’s masterpiece and whether it makes a billion dollars or not, it’s a triumph for mainstream cinema. The dream isn’t real – far from it – but you won’t leave the cinema disappointed. You’ll more than likely want to talk and talk and talk about what it all means. That’s the sign of great cinema, no?

Rating: ★★★★½

UK Release: 16th July