I really loved this game!! It seems like you had a really clear vision and executed really nicely on it. It was a beautiful game too, nice animations and parallax layers. I couldn't believe there was a boss fight to top it all off, well done! Some more "punch" for the bullets would have made it feel even better. Not sure if that was left out due to time crunch, but if not, this is a great video on adding particles, lighting, and impact animations for bullets. How to Make 2D Pixel Bullets with Collision Effects in Godot It's helped my games out a lot.
Really great job here!