This part of the game is personally the best. First of all the puzzles you do to even collect the music sheets vary in addition to being very creative and fun.
The orchestra itself was perfect. the challenge and tension in trying to conduct it flawlessly while listening to one of the most charming OST of this game. Then when you finally do it you are rewarded with arguably the coolest cutscenes ever. To top it all the last part of the stage where the orchestra refuses to leave the cave, because this is their duty, is just amazing man.
The world of this game is In general very charming and easy to relate to, but this scene in particular was so special.