"soft" objects have been around for quite some time. Search for "softbody" or "soft body", and you will get numerous scenes displaying many kinds, probably hundreds if you include Phunbox 1. A lot of them use springs from before beta five and may not function right, but they've been made with springs, hinge stretching, and even water. For a long time, they were sort of a fad. As soft bodies go, this one is rubbish. And by no means is this one bouncy, as is claimed in the title. Look around at how some of the others are made for inspiration on improvements you could make.
Wait, I checked who the author is. Physicsguy? Haven't you been around long enough to know what a soft body is?
Lame. There are MUCH better ways to make walking mechanisms. You should look around at other walkers for inspiration, because you will get better looks and better performance out of a more complicated mechanism. Many people wouldn't even call that a walker.