When it says in the badge description you will get after song I got the badge during the song and it kinda got in the way so I wish it will actually reward after the song.
I thought if I skipped the whole level I wouldn't have to play the boss. But also when I tried to beat the boss I couldn't move around and there was no unlimited jump so the boss is pretty much impossible. Overall I would give it a 5/5.
because you run in the sky ;)