Oh, I saw your game on the Jonas Tyroller video :) Congratulations on the game. Cool concept.

First of all congratulations on your first release, I have to say that the quality of the graphics and the level of polish is very impressive.
But I think you could make it even better by changing some little things.

You have no level tutorial to present the controls to the player. The player's first experience is already negative, as he starts in the middle of the battle and is killed several times until he finds the controls.
I know you put a message at the bottom of the screen saying press ESC to see the controls, but with the player trying to survive the enemies and dozens of bullets on the screen it is very difficult for anyone to notice this message.
Maybe it would be a good idea to have a quick level tutorial to introduce the controls.

The game is very punitive right now. I believe the first impulse of most players will be to try to destroy as many enemies as possible, but this is quite complicated since to hit the enemies you will necessarily have to stay in their bullet stream, and currently the player's life is too low to do this even for a very short time (or maybe I'm just terrible at the game :) ).
But even for a game that requires skills, the player's first levels and first contact with the game should not be so punishing.

My best recommendation here is to implement some analytic lib and use some funnels and metrics to identify where players are leaving, then use the data to balance it better.
Data such as how many times the player dies until he can complete the level, what levels are accessed by the player and what levels are never reached, average session time etc, this data would be of great help in balancing stuff.

If you already have some analytic lib in place, could you share some data? I would love to see that.

Good luck and again congratulations!

There are an absurd amount of collision problems.