Thanks for the compliment! The Scale Boy visuals and animations were the first thing I made in the project to learn how Godot works, and I'm really happy with how he turned out :)
I don't think it's any different from placing a muscle somewhere; It's simply another mechanic added to the creature. I'm not talking about a joint that does anything on command to the user, but rather one that does something when it touches the ground. Isn't it the same kind of "controlling the creature" you get when you decide to add a bone to stop two joints from rotating?
Hey, An interesting suggestion I'd like to make after playing around with this simulation, and watching some videos on youtube, would be a special kind of joint which completely stops a creature's "brain" when it touches the ground.
I see several people, including myself, try and make creatures that walk on legs, but often these aren't utilized, or the maon body is dragged along the ground anyway.
Having a joint which isn't allowed to have contact with the ground might yield some interesting results, as only creatures keeping these joints off the ground will progress. This could be visualized with just having the joint be a different color. As soon as it comes in contact with the ground, all the muscles in the creature will stop responding to input and stop contracting or expanding, effectively dropping the creature on the ground. This means it will no longer be able to advance further, meaning logically that creatures keeping these joints off the ground would survive longer.
I don't believe this could be a very difficult addition, though of course I don't know the specific workings of the system.