Wayne McGregor premiere, Royal Opera House, London

A wondrous world of stick people and twisty torsos

Infra, Wayne McGregor's world premiere for the Royal Ballet, is full of changes. You can see McGregor trying things that are new for him, new for his dancers. It makes for a less finished work than his recent Chroma, with some rough edges and weaker patches. But there are always ideas here, and they're always going somewhere.

McGregor's first large-scale work as the Royal Ballet's resident choreographer is a collaboration with the artist Julian Opie; this first night was filmed for BBC2. Opie's set designs include a video wall: a wide strip of screen hanging over the dancers' heads.

Film installations are now common in dance. Infra is unusually good at integrating screen and live action (though a technical hitch did delay the start of this first performance). The screen shows electronic figures walking. They're stick people, with distinctive round Opie heads, but their body language is believably natural and easy. One swings a briefcase; another teeters in high heels. Those electronic passers-by root this dance in a stylised but everyday world.

Below them, dancers break into characteristic McGregor moves, thrusting out hips or limbs, torsos juicily articulate. In his recent dances, McGregor's steps have been just as twisty but much less brutal. Instead of sending dancers walloping through the moves, he gives them more room to breathe, shaping his steps into phrases. The dancing is still fast, with the same jutting exaggerations, but it's much more legible. He is showing off his dancers' style as well as their strength and flexibility.

Max Richter's music mixes murmuring electronica with string quartet writing, scratching or mournful sweeps of sound. McGregor responds with newly emotional dances. This isn't a story ballet, but it has dramatic elements that I had never seen from this choreographer. There are even literal dramatic gestures, a kiss or a cry.

In one of Infra's best scenes, couples line up in boxes of light. They're all dancing different duets, but patterns start to emerge, variations or echoes of the same steps. Relationships emerge, too. As she bounces up on pointe, Leanne Benjamin's fierce little nod suggests a quarrel with her partner, Edward Watson. Women snap into poses, giving their footwork a conversational rhythm. More couples arrive, until the stage is teeming with duets. It's a lovely image of life going on, all the individual stories within a crowd.

Infra is an episodic work, following Richter's music in solos, group dances, dramatic and pure dance moments. Sometimes the pace sags, or McGregor changes gears too obviously. Lucy Carter's light design helps to define episodes and numbers, framing the dances in squares and shafts of light. It is atmospheric, though her softest lighting blurs the dancers' expressions. Moritz Junge's costume designs are simple, putting the dancers in plain tops and trunks.

During Lauren Cuthbertson's solo, people in street clothes start to cross the stage, like Opie's digital crowd made flesh. As they stroll by, she sinks to the floor, crying. It doesn't quite work: her silent howls are too big, the pacing slightly off. It's still a bold moment, however, and a fascinating change of tone from McGregor.

His dancers look delighted by the challenge. Eric Underwood stands out in a swaggering solo, his torso swaying with brilliant assurance. There are strong, alert performances from Benjamin, Cuthbertson and Watson, all McGregor regulars. The young Melissa Hamilton, still in the corps de ballet, is lucid and pugnacious.

This triple bill opens with Glen Tetley's Voluntaries and Flemming Flindt's The Lesson. Johan Kobborg is brilliantly creepy in the cartoon violence of The Lesson, twitching with repression and madness. Roberta Marquez makes his doomed pupil first sugary, then desolate. Laura Morera gives the pianist's gestures a kind of pedantic fury.

Voluntaries, Tetley's ballet of dancers surging about in patterned body tights, needed more focus and punch. The men come off best. Rupert Pennefather partners strongly, while Sergei Polunin dances with bright confidence.

To 26 November (020-7304 4000). 'Infra' will be on BBC2 on 22 November