Defeat the final boss with no effort: Fly ahead and repeatedly crash into him before he is all the way on the screen. He won't shoot at all, but your shots still hit him. Be sure to heal and charge as needed.
The art is a great start, well designed and balanced, but it looks like a rough draft. Please get someone to do a final draft from these sketches. You will have a beautiful game!
No, it's fine the way it is. It's intentional, it's not about being perfect.