I liked the game a lot, I was trying to make the most efficient frog possible, but when I turn on the "show muscle contraction AND EXPANSION" I could see why it take so much time and efford for the movement to be more efficient. Because muscles don't expand, it only contracts, thats why we need the triceps in our arm for example. Because if we just have the biceps our arm could not make oposite force in the bones to do pushups for example. 

A limb has to have always a protagonist and an antagonist, to do oposite movement. maybe just removing the expand feature and let the users know that now they have to put one muscle to pull at one side and the other to pull the oposite side while the first just dont let the limb to turn 180º, thats, I belive, will make the organisms a lot more efficient in evolution.