Controls are pretty awkward. At first I just wanted to use the arrow keys to move and found using the mouse to control yellow platforms annoying, but then I understood that I needed to be able to move the platform and myself at the same time. I would just recommend supporting W to jump since the spacebar feels off for this. X to attack also feels awkward with WASD controls. Q or E would be more conventional choices, or even just use the click for this purpose again!
I like the jump height, but maybe a bit slower?
There are some good ideas here so I hope the later chapters get flushed out.