Thank you for the feedback :)
About the music, I wanted to have a really happy day theme, and a gloomy night theme with some tension with instrument changes, but same bpm, same melody... But I'm not a musician, and I wasted half a day trying to learn something, when I realized, that it is impossible. So I did what was the best for the jam: Downloaded a free music, and changed the pitch and volume during the night
But you are definitelly right, how you describe it and what was my intention as well could have worked better