That was a fun exploration!
I liked how you made it possible to change the legs, independent of the arms; I don't easily recall another 2d game doing something like that. I see a lot of potential on this idea, since it makes room for really varied puzzles where you have to figure out the specific combination for each situation.
I finished it, and the biggest issue I had was the commands to swap parts, It was a bit strange to use the same direction buttons to morph while I was making a quick action (specificly on the part where you have to get the tires, then quickly get the legs to jump again while paying attention to the timing of the lasers...) maybe if there was one button to swap between the different legs, and one to swap between the different arms, it could be more inctuitive.
That's what I have for now, still a cool ludum dare game :)