Amazing. I'd only seen this kind of movement one other time, but not by so many or so brilliantly choreographed. In fact, it was a completely different context: Mark Rylance in his wondrous performance as Olivia in the 2012 Globe production of Twelfth Night. youtu.be/HVubWP3p62s?...

Fantastic

It does look creepy. It is keeping vertical movement minimal that is key I think, to hide any sense of steps.

Indeed. Some real dance discipline and skill here: these are properly trained dancers: given Russia's deep ballet tradition, I suspect many of them may be ballerinas working off-piste.