Im not saying is a bad desing, but they could have paid moré attention to the way the joints behave, and yes if we start looking for problems, i Will point the lack of sensors, the natural resistance of leg to the movement, the aestetical look and feel of it, etc etc. i guess this is moré like a walking leg prototype, im sorry if it sounds excesive, but i really love this subject and for a guy who almost got a master on robótics, well i tend to pay too many attention to details, Cheers

ps: if some words aré mispelled blame iPad autocorrection function