Thanks for the feedback!
The license requirement is not listed anywhere on the jam page or in the challenge description. I will take your word for it but in the future may want to have the jam organizers make that clear so that you don't have to copy/paste that info on 400 entries.😄
There is music but it's random, sometimes you just get ambience and no music until the day/night changes, this is intentional. (unlucky!) The disappearing objects is intentional too, the player can wait for something else to spawn and it naturally cleans up old objects as the tower / play area gets higher.