I've put together a very rough version of the first 10% of Musume's first level. There's a lot of polish to come, but this should give an idea of what I want the gameplay to feel like.
Also, I implemented gamepad controls. Jumping on those platforms and attacking the boss proved too tricky with the keyboard (at least for me, since I'm not really used to playing games with a keyboard).
Again, this is super rough. Expect more polish when you see the game again.