It's astonishing how well this game works. It's fun to picture the level in my mind – just listening to the sounds. And I believe there are so many possibilites for additional levels (eg. spaces you don't have to touch but make certains sounds. Moving tiles etc.) The puzzle ist to make a plan how to reduce the complexity of a level in your brain (like: always go 2 then up then down then 3 then up then down...).
This could be a really cool mobile title. Congrats!
P.S. HWestby ist right with their suggestions. Additionally: I did not get what the green triangle does. And I think objects that do the same gameplaywise should be of the same shape and color.