It's a very interesting idea but you can definitely feel it's not polished. I had no idea what the spinning ball was for until I hit the boss with it and then I had no idea what the colors meant. Maybe a short tutorial or even text in the description of how to beat the boss would be nice. Good job on your first game though! It is a very difficult thing to accomplish, and you should be proud that you even submitted something! Being able to submit your first game is a win on its own.