Interesting game, I hope you don't mind the Luftrausers comparisons but I played it a lot so they're inevitable for me:
I'm not the biggest fan of how prevalent melee enemies are, it shifts the gameplay from a cool dogfight to a messy escape where you're punished a bit too much if you ever stop running.
Also I'd prefer if the gravity didn't act so linearly, you can't really do cool stall dodging like you could in Luftrausers.
Enemies being able to enter the water without any trouble makes it just an obstacle and the fact that there's no clouds means you can just climb forever.
The gun sounds annoying and it doesn't seem to ever be worth using over the laser.
The moving background reacting to your inputs is a really cool idea and the visuals in general aren't bad.
Pretty good for what it is but you gotta give it something unique if you want the game to stand out form Luftrausers.