I have some insight into what is required from a design standpoint to allow this kind of performance and I am astounded at what these guys are doing. One of the challenges is that each joint requires forces to be applied to move, right? Well, the exact magnitude of those forces needs to be constantly adjusted by complex software algorithms using force-feedback from that same joint. That force-feedback mechanism is challenging in and of itself, but when you consider that we're not just taking about one joint here - we're talking about a system of many joints with multiple (and different) degrees of freedom that are all working together to control movement, CG, etc.
Incredible.
To me, the only thing limiting these things from taking over the world is battery technology.
