For me, Little Miss Sunshine is the best film of the year so far. It’s as close to perfection as two hours spent sitting in a darkened room is likely to get. It starts strongly, gets better and better, and ends perfectly, with one of the most hilarious and demented sequences ever committed to celluloid.

But, truth be told, for the first few minutes it’s merely very good. First-time scriptwriter Michael Arndt makes the brave choice of sacrificing laughs for character development in the first third, safe in the knowledge that it will eventually pay huge dividends. For what’s superficially a comedy, albeit a dark and frequently heart-breaking one, it’s a risky gamble that would fall flat without a rock-solid script and a cast that can do it justice – and it’s lucky that its directing husband and wife team of Dayton and Faris have both.

So, we are introduced to Richard Hoover (Greg Kinnear), a motivational speaker with a nine step plan that nobody but him cares about. His wife Sheryl (Toni Collette) is too busy worrying about money and keeping her deeply fractured family in one piece – brother Frank (Steve Carell), a gay Proust scholar turned failed suicide; her Nietzsche-obsessed son Dwayne (Paul Dano), who’s taken a vow of silence; and her daughter, chubby bespectacled would-be beauty queen Olive (Abigail Breslin). When Olive unexpectedly gets a place in the Californian Little Miss Sunshine contest, the whole family, along with Richard’s cantankerous heroin-addicted father (Alan Arkin), are forced to crowd into their VW van for a cross-country road trip. And from that point onward, everything that can possibly go wrong does.

On paper, it shouldn’t work half as well as it does. Any summary makes the characters sound like one-joke clichés – “he’s a motivational speaker who can’t even motivate his own family!” – and it’s hard to tell just where the film’s colossal depth comes from. The easy answer is that, of the central performances, almost everyone is doing the absolute best work of their career – it’s hard to remember another ensemble cast that played together so perfectly. And all of them are left standing by 10 year old Abigail Breslin: it’s her job to hold the film together, just as Olive keeps her hopelessly dysfunctional family together, and Breslin manages it perfectly.

But the difficult answer is that Little Miss Sunshine is that rare film that, though billed as a comedy, dares to plumb depths of human tragedy that in theory are very far from being funny. It’s a story about the meaning of failure in our modern world, about the horrible toll of trying to succeed and sometimes of even daring to compete. It really is painfully sad in places, but despite that (or more often because of it) it’s also frequently hilarious.

Of course, there are imperfections if you really look for them – but nothing that ever comes close to derailing the film. Some of the background characters are painted a touch too broadly, but then it’s the grotesquery of those around them that that really puts the Hoovers into relief. Towards the end it risks going over the top, but because we’ve seen the family pushed far beyond the limits of endurance it always remains on the right side of believable.

And ultimately, such tiny flaws are endlessly outweighed by the quality of script, direction, music, acting and pretty much ever other element of Little Miss Sunshine. I honestly can’t think of another movie this year that has got everything so right, or that made me laugh so hard, or that left me so completely moved.