Thank you. I'm glad you liked the music since I'm very happy about how it turned out. I know now that the tracking bugs can be a bit difficult. It's not easy getting the difficulty right when you are on a time limit. ;)
I didn't have much time to balance the game so I guess it can be difficult if you don't know where and when the enemies will appear. If you start missing the tracking bugs you're pretty much done for.
One of my favorites so far. It's a bit hard to keep track of what to do at times. A quest log would be great. I also accidentally closed the game one time by clicking on the cross in the top right corner so maybe make a warning message to ask if the user wants to close the application.
A good start for a game. It's a bit hard to see the enemy bullets. Especially the slow ones from the boss. Also the boss has way to much health in my opinion. Other than that, it's great. :)