Edit: Thank you so much for this fun simulator!
I tried to make a rolling creature made of two wheels joined together by an axle at the center; and muscles between the opposite spokes.
I think you have a raw input for rotation, since my creature wobbles back and forth: My guess is the angle jumps from 359 to 0, which is bad for my use case.
What I would love, that would allow a continuous rotation, would be to split the rotation into sin(angle) and cos(angle) as 2 inputs. This allows nearby angles to get transformed into nearby (sin,cos) points in 2d space, and would allow for continuous rolling of creatures!