Wayreap's Battle, Barbican, London<br/> In Your Rooms, The Place, London

A group of giants lead a captured human king to their undersea kingdom. Their faces are covered by masks - snarling, sharp-toothed for the giants, bright green and blandly smiling for the human. The dancers undulate, bodies rippling to show us that they're under water.

Wayreap's Battle, danced by Amrita Performing Arts, is an epic of traditional Cambodian theatre. In the 1970s, under the terror of Pol Pot, almost 90 per cent of Cambodia's artists were killed. Since then, survivors have worked to reconstruct their arts and culture. Choreographers Pok Sarann and Pum Bun Chanrath danced this story before the terror. Their new version has a mix of glitter and friendliness, with elaborate costumes and lively incident.

The story comes from the Reamker, a version of the Indian epic Ramayana. When the human king Preah Ream is kidnapped by the giant Wayreap, the monkey god Hanuman goes to rescue him. They're accompanied by two narrators and a traditional orchestra.

The dancing is an elaborate form of mime, with more gestures than steps. In an introduction, the company demonstrate how different characters will express the same emotion. Heroes laugh elegantly, while giants roll their torsos in outsized (but silent) ho-ho-hos. The monkey soldiers giggle, wriggle and stick out their bottoms.

In this style, all roles are played by masked men. Wayreap's Battle has just one female role, a giantess. Here she was played by a stocky man, who sways through elegant poses. It's comic, without turning into drag.

The pageant is always ready to stop for a lament or comic scene. We see the monkey army on guard, falling asleep and squabbling. The animal moves are among the most appealing: the monkeys scratch, catch fleas, scamper lightly about.

The sea creatures are delightful. Crabs, with eyes on stalks and pincer gloves, move sideways in deep, squatting pliés. Seahorses have headdresses like chess pieces and hands held like fluttering fins. A school of fish sweep through.

When Hanuman fights the sea creatures, he recognises one (a monkey with a fishtail) as his own son. The sea monkey can't fight without betraying somebody, his father or his stepfather. "How can I be an ungrateful child?" he asks, before withdrawing from the battle. It's a serious dilemma, touchingly shown.

Perhaps five minutes into Hofesh Shechter's new In Your Rooms, the voiceover says: "Let's start again. I can do better than this." Then there's a pause. "No, I can't."

The audience laughs, but how well Shechter can do is the question. This rising choreographer, born in Jerusalem, based in Britain, has been singled out by three of London's biggest dance venues, and his new work In Your Rooms will move on to the Queen Elizabeth Hall and then Sadler's Wells. The piece will develop, adding live music at the Southbank and more dancers for the Wells. The larger venues co-commissioned the work, setting it up as Shechter's breakthrough piece.

That cranks up the pressure - and it shows. In Your Rooms has much in common with Shechter's Uprising, the 2006 work that opens this bill, but it's longer and less sure of itself.

The new work starts with a discussion of structure, about formal structures as a way to organise chaos. As the lights switch on and off, we get glimpses of the dancers. In one, they're arranged in ranks, doing obsessively neat, repeated gestures; in another, they straggle across the stage, limbs swinging loosely.

Shechter does know how to get his dancers moving. Kicking through boxy steps, arms and shoulders pumping, they look both taut and at ease. Longer sequences have a churning energy.

But In Your Rooms meanders, chopped into short bites by the voiceover and the blackouts. One dancer draws a chalk line across the stage. The others dive and dance across it, smudging it away. This is a work that comes and goes.

Uprising is much better: tighter focus, less burbling. The eight men dance and quarrel, hearty slaps turning into a fight. Shechter adds distinctive, simian steps: a loping run on hands and feet, a lively scramble.

'In Your Rooms' is at the Southbank Centre, London SE1 (08716 632 500), 4 & 5 May, and at Sadler's Wells, London EC2 (08444 124 300), 28 & 29 September