I'm finding on a lot of submissions the box on the page is just a tad too small to be able to hit the fullscreen button and when you hit the html "fullscreen" button you just get the same thing but with a black letterbox, which in your case cut off about half the UI on the left. Fortunately I could just make out 1 or 2 pixels of the Unity blue fullscreen logo that I could click and it worked fine. Not sure if just my browser or not but it is only happening on some games and not others.
As far as your game. Great concept. I'd like to see some sort of progression though. Maybe you can create a song for each continent and then when you're done all the continents come together for the final ensemble?
I think you should keep developing after the voting is done, looking forward to seeing more.