First, let’s be clear… Avatar is much more than a film. It’s a prescribed cinematic experience. Pure effect. The greatest sideshow on Earth.

Cameron's aim is to take our franchise-frazzled minds and plug us back in to the mainline; to conjur the wonder of those early silent-movie audiences, aghast and alarmed as a steam-train chugged from horizon to foreground.

Like Avatar's hero, injured marine Jake Sully (Sam Worthington), he wants to blast away the past and see through new eyes.

Avatar is the new benchmark for escapist entertainment; the ultimate on-screen dream. More suspension of self than suspension of disbelief.

As Jake dives in and out of his split human/alien personalities, Cameron is equally urging us to leave our burdened minds and busy bodies behind - to sink into our seats and immerse in a virtual world.

In the febrile jungle of planet Pandora, it's a thrillingly alive world of whooping devil-monkeys, scuttling super-spiders, fluttering titan-orchids and bioluminescent air-jellyfish.

The ground is patrolled by hammerheaded, Triceratops-like behemoths and saber-toothed jaguar-giants, while immense, lizard-headed mega-birds rule the air.

But Cameron keeps us connected by not pushing the otherness into hokey, adolescent alien-sketch territory. This isn't an open-air version of the Star Wars cantina: weird for weird's sake.

It feels equally distant and familiar. Like an advanced version of our own world; as if Cameron has run the whole of the current ecosystem through some kind of evolution extrapolation software.

And into this wild and wonderful arena… Enter Avatar Jake, a hybrid of human and Na'vi - the blue-skinned, golden-eyed, oversized indigenous people.

"A marine in an Avatar body", snarls Stephen Lan𒀰g's fera♒l colonel. "That's a potent combination…"

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In fumbling hands, this could have badly misfired - strange and silly instead of curious and moving.

But, unlike his last film, Cameron doesn't over-season the sentiment. He drills straight through to the emotional core: his leading man's wrenching inner-space odyssey - from interloper to insider to outcast.

But the success of the human/Na'vi love-story thread is mostly down to Salౠdana. Her subtle, spiky performance is a delicious foil to Worthington's wide-eyeꦯd neophyte.