Overall a really nice game :)
I like the mechanics, and how you managed to build the levels with such a nice difficulty curve. The plataforms that change whenever you jump are my favorite once, I think I just like combining mechanics like this, since it gives you something more to think about. The art style is also nice, simple yet very clear.
Since you mentioned you want to keep working on it after the jam, I'll just add my two cents. I think you could add more different types of plataforms, maybe ones that get larger or smaller the longer you stand on them, or plataforms that you must not touch. Also you could clean up the color scheme even more then, so there is just one color associated with each type of plataform.
By the way I also made a platformer, but instead of the platforms, you change size. I would also appreciate some feedback if you have the time :)