I've got no clue to how this game works, I have tried multiple times to make something bipedal but they all just fall to the ground and proceed to crawl.
I can tell you what worked and did not work for me
a) having "arms" or a tail to help balance the creature helps keep the creature upright and gives the creature more time to learn to walk
b) having "feets" also helps maintain balance.. your mileage may vary choosing between a triangular foot or a "line" as feet.. my personal preference is to use triangles but make sure they are not too rigid (can happen if you make your triangle too wide..
c) long time between generation is both a blessing and a curse.. on one hand it gives your creature time to learn to walk, on the other hand it is hard for the creature to stay upright for long and when it falls over it tends to crawl... (with their arms)
try starting from a "three-legged" creature (with a very short third leg as the analog for the body) and then evolve your model from there..
this was my "bipedal" walker
and this is it in action
