Alright.
It's about GODDAMN TIME someone made one of these things that's actually original. <to unoriginal developers> Get with the program! It's called adding ENEMIES!
Thankfully, you were smart enough to make one of the games that was original. I liked the music box idea. But I think it would be better if the music was less repetitive and that those boxes unlocked music.
My only problem is that it only started to be a real challenge at level 14. Before then I only had to really think when I wanted to aquire all the fish.