I did realize I could shoot the fireballs to stop them! I did not realize at first, but at some point it felt natural to just try shooting them. For me this made total sense, and I did not have a problem figuring this out at all :)
I often just put all my upgrades into movement speed, but maybe I should have put a bit more into reload time. When the boss began I was usually also at one or two lives, so there was not a lot of room for mistakes. But as I said, I dont think of this as a problem. It is okay for a game to be challenging :)
Haha, needing to follow tutorials makes total sense! I have been doing game dev for quite some time now, and I also still follow tutorials if I want to learn about certain features of Unity. However, I think it is great that you try to make your own original stuff! This is what is most fun for me, and you can learn a lot of things from it. ^_^ I am happy to hear that you find peoples comments encouraging! This is one of the greatest things of a gamejam for me. Just hearing from many other game developers and talking about gamedev :D
Sorry for the long text, haha. I am curious what you will make in the future! :D