The Birds, National Theatre Lyttelton, London

Wow! Look at that girl, springing from her trapeze into her partner's grasp, then twisting round and leaping back! And how about that other acrobat, sliding down two lengths of fabric, then turning over and over to hoist herself up, and doing an upside-down split? Yikes! There's a man swinging over my head and somersaulting as he goes. What fun! Now, when do the animal acts come on?

Peter Brook has a lot to answer for. With his 1970 Midsummer Night's Dream, in which acrobats and tightrope walkers created more excitement than one would expect from just listening to Shakespeare, he gave birth to a theatrical generation less interested in plays than in playing games.

The director Kathryn Hunter, a fan, has acted in several productions of Theatre de Complicite, that clique of arch grotesquerie, so you know what you're getting in the Birds, and it ain't Aristophanes. The speeches in this version, nearly three hours long, constantly give way to avian gymnastics or, persisting, become mere foreground noise.

Euelpides and Peisthetaerus – or, less formally, Eck and Pez – are two humans who, fed up with the city, assemble the birds and exhort them to build a city of their own (traditionally Cloud-Cuckoo-Land; in this version, Ornithopolis). But what starts out as a vision of utopia soon becomes compromised by internal power struggles and battles with the gods. Birds who find fault with Peisthetaerus's government – "dissenters who have no part in democracy" – end up plucked and roasted.

It's a simple story, but a story that is difficult to follow and even harder to engage with, given the emphasis on distracting turns and the laboriously madcap tone. Poseidon is played by a woman in short harem trousers who whacks miscreants with her handbag.

Hercules has a broad American accent, and when Pez celebrates his marriage to a goddess, he wears a Stetson, and his bride is a white Statue of Liberty. One expects that anyone naive enough to ask an explanation would be told, with a broad smile of pity for the literal-minded, "It's satire''. The music of the on-stage band is a similar puzzling jumble. At one point, for instance, the beginning of the "Habanera" segues into the spiritual "I'm On My way" as Pez chases Eck round the stage with a whip.

Some couplets of Sean O'Brien's adaptation aim for grandeur: "Woe to the world that once was ruled by wings!/O birds, I grieve for you that once were kings!" Much of the dialogue, though, relies, for humour, on simple outbursts of profanity or cutesy slickness: A disco bird raps, "Our personal service is 24/7./Come fly with the birds. You'll believe you're in heaven." O'Brien ends one line with "villain,"' the next with "kill 'im," and also "rhymes" "strategist" with "I'm a Clausewitz." Stephen Sondheim, I think, can sleep easy. Hayley Carmichael plays Eck as if competing for the pluckiest-little-bunny title that Felicity Kendal is finally handing over.

Perhaps the worst thing about this Birds is Marcello Magni's Pez, his coarse clowning and word-chewing speech ("Holy word comes out sound like "Hollywood") the very incarnation of its horrible spirit of being larger than life and smaller than sense.

To 14 August (020-7452 3000)