A 3D animation movie opไening the world’s premiere film festival? A thousand chin-stroking journalists donning oversized spectacles before they get down to the serious business of the new Haneke? Now that’s a tough audience…

Pixar, as ever, rose to the challenge, win▨ning tears, laughs and a sizeable round of applause with their tale of a grouchy OAP who attaches thousands of balloons to his house and floats off to South America for the adventure of a lifetime.

The 3D is spectacular. It’s spectacular before the movie even begins - from the moment viewers are allowed to float over the turrets of the famous Disney mansion.

But Up isn’t about the 3D, just as Toy Story wasn’t about the CGI. Pixar’s mantra has always been story, story, story, and Up, as ever, is all about the characters. And the observations of human (and animal) behaviour. And ꩲthe exquisitely timed physical comedy.

The first half-hour is extraordinary, f꧋irst introducing us to shy young Carl Fredricksen – a dreamer, a would-be adventurer – who meets a like-minded girl down his street, and then whizzing us through the decades of their life toge༺ther until a septuagenarian Carl sits by her coffin, broken.

A stunning montage full of humour and pathos, it rivals the famous breakdown-of-a-marriage montage in Citizen Kane. Hyperbole? Not a jot of it – there were hundreds of dark spectacles being removed so hardened hacks could swipe at tho🌺se tears.

Carl and his wife Ellie had always dreamt of adventuring in Venezuela, and so it is that Carl now hits u👍pon his gorgeously surreal scheme to float up, up and away. W🍒hat he didn’t bargain for was the over-eager cub scout standing on his porch, up there in the clouds.

Which of course means the second half of Up speeds everything up, unleashing a flurry of verbal gags and a host of chases involving a giant bird, a pack of talking dogs (thanks to special collars that translate their growls and snarls – is John Lasseter and co. taking the Mickey out Disney♔’s heritage of talking animals?) and a nasty hunter.

As with W🐟ALL.E, there’s a feeling here that Pixar haven’t yet got the courage of their convictions; that the animators want to reinvent mainstream animation, to make it emotional and thematically adult, but are wary of jettꦍisoning the frenetic set-pieces in case the kids get bored.

Which isn&rsꦿquo;t to say the second half of Up isn’t good – it’s consistently funny and continues to pulse with emotion whenever it pauses to take a breath – but it’s not AS good, the life-or-death action containing no real sense of peril.

Gorgeously crafted, the set-pieces nonetheless feel a little… cartoon-y. Which would be a stupid thing to say if it were not for the fact that the first hal🦂f of Up feels anything but.

But as ever when criticising Pixar, all grouches seem a little churlish – these guys remain so far in front of the competition it’s embarrassing. One thing’s for sure: Cannes 2009 is up and flying.