They probably used some PID controllers too. I made a very simple one for a computer game a few weeks ago (pretty much a self balancing segway, good enough for a FPS character). I should try giving it feet instead of a wheel, should be fun.
They can keep standing when there is stuff thrown at them. If I were to program that, I would model reflexes like the achilean reflex with a PID controller. Which is a mathematical formula with parameters that comes from their DNA, not a remote control operated by a human.
2 tequila
3 tequila
Floor!