OH MY GOSH!!!!!!! I love this game so much! A music-making game with the sound of monkeys / apes / baboons? GENIUS!
My only piece of feedback would be for the sounds to update more regularly when I place a character outside of a music box. When I had placed all of them outside of the boxes, the song continued to play and I had to close and reopen the game to start again. It would also be cool to have more varying sounds, but I realize that that was probably out of scope for the game jam :)
Overall I had so much fun playing around with the different sounds and experimenting with the creation of new songs. This is an example of something that is so simple but SO effective and just so cool. Well done!