alright
I've played this kind of game many years ago. It was called wind-something, I can't quite recall the name of the game but it was an awesome game made by some asian guys. You have the same gameplay idea but the graphics are pretty bad in your game. The missile is hard to spot for example.
I don't quite like that after you die, you can spawn inside the boss and if you don't quickly realize that you will die again. Also the projectiles generally speaking fly too fast. I see this kind of game more about positioning yourself correct rather than having lightning fast reflects to dodge incoming projectiles.
My review maybe little harsher but that's only because I've played this kind of game that was 10 times better and I can't help but compare your game to it. It's an alright game nevertheless.