Difficulty is weird, great proof of concept. I would add loading screens between levels to distinguish the difference. I would add some kind of movement to the orb, be it random or controlled by the mouse. You could use z/x to rotate the orb, allowing more movement. You can kind of speedrun the levels (they're too easy), as the real difficulty is in the boss. I would add some form of difficulty be it stronger enemies, more difficult platforming, or a timer. Other than that a great game! I just don't feel like it's finished, even for a jam game.