Of course the robots have been pre-trained and the movements are scripted, and nobody is claiming otherwise. But there must be a lot of autonomous balancing taking place. At one point you can see the robots adjusting their feet slightly different although they are all in sync, and that catapult does not look like its movement is exactly the same every time. It is just super impressive.
Does anyone remember when Honda's Asimo robot clumsily fell down the stairs during a demonstration[1] and we thought we were safe from a robot invasion by just moving to the upper floor? That was about 20 years ago.