Nice game! I like the concept a lot and the art is cute and well polished.
I felt like the controls were unintuitive for some reason. Maybe make it WASD or arrow keys instead of space/shift. And maybe also dont swap the controls when you swap characters (not sure about this one).
Otherwise I feel like it just needs more content and mechanics to keep the puzzles interesting. I think pressure plates would be great to add, since it requires one of the blobs to be standing on it for it to be active. Maybe introduce a third blob somehow. Maybe add walls that you can push back and forth from either side.