The second Object was the only one I've found.
I guess you have to play some right melody on the piano but I couldn't find a good clue.
On the piano itself is something to see but some of these signs are didn't match with the signs on the piano keys. Much more Time would be way more pleasant to play, becasue otherwise the player will be really fast frustrated.
I really like the artsyle in this game! :) I also found a suspicious long object with to spheres.