According to the law of averages it had to happen some time – a family movie that's actually really, really good. Whether it was because it was aimed less strictly just at kids or because it was the same old template but with a far better script and visuals than most, I still can't decide.

The same old template is two-fold; even though you feel like an average face in the crowd who'll never amount to anything, you're special enough to change the world. The other (always as popular as it is ironic in Hollywood movies) is not to fit into the roles society imposes and never to conform, to be creative and let your imagination guide you.

The embodiment of the themes is Emmett (Pratt), a construction worker who follows the rules, doesn't rock the boat, and has apparently drunk the Kool Aid of thinking his unexciting life is awesome (to the extent his favourite song on the radio is called Everything Is Awesome).

But when he finds a strange artifact and a mysterious, beautiful girl on a construction site after hours, it's the first step on a wild adventure. According to the moral of the story that we're all special, Wyldstyle (Banks) thinks Emmett is a mythical figure called The Special, the one the prophecy says will free the world from the dictatorial rule of the evil President Business (Ferrell).

Wyldstyle introduces Emmett to a whole new universe outside the city and a host of characters engaged in the struggle for freedom, from the old sage Vitruvius (Freeman) to Wyldstyle's egotistical boyfriend Batman (Arnett).

The final few scenes give the film a meta-layer I won't spoil, one that causes everything to make an overarching sense and fits in perfectly with the ethos of what Lego means to everyone who's ever loved it. It explains everything from the weapon President Business wants to wield on the hapless citizens to how the Millenium Falcon can show up just when the gang needs a hyperdrive, and while it makes the proceedings a little bit mushy, it's a very cohesive and extremely clever narrative device.

But the real magic is in the film's continual willingness to take the piss out of itself – the characters do it, the jokes do it, even Lego itself does it. Every time there's a faux-profound declaration or plot turn, something hilarious appears to put a pin in it, and the pace of the jokes coming thick and fast only helps.

And while all this is going on in the script, the visuals are likewise something we've never seen. Sydney CGI house Animal Logic has executed the unique creative decision that a Lego world should mean everything – including characters, buildings, the landscape, explosions and (in one eye-popping sequence), the whole ocean – is made of Lego bricks.

I was reminded of the final scene of Who Framed Roger Rabbit, which Zemeckis and his team said on the DVD was a nightmare to wrangle because they were dealing with rights issues surrounding characters from competing studios. Somehow the names of characters and vehicles from across the media are all here despite the myriad rightsholders who own them, and kudos to the producers for thrashing what must have been a legal minefield to make it happen because the writers realised a real Lego collection would indeed have Batman, Han Solo, Wonder Woman and dozens of other familiar names.

It's a supreme irony that this movie - like so many nowadays - an overblown ad for a toy or other media property, but it's one of the best movies in the genre you've ever seen.