There were so many prototypes for the animation & controls system. It was a mix of techniques from a talk about Overgrowth and research into IK & PID controllers but applied to fully physics based ragdoll. Ended up using custom controllers which has some PID similarities but simulates muscles instead of a motor. 90% of the feel of Human is actually the result of Unity physics & joints - there were at least 3 prototypes that felt pretty much the same although they were using completely different approaches. Took the one that suited particular game mechanics best - it takes a lot of tuning to get all the verbs I want in the game - push, pull, climb, carry, place & align objects, use tools, etc. Gang Beasts is a brilliant game and great example of physics based animation. I definitely took a closer look at it, especially when people started pointing out that we have similarities.