I'm not sure what happened at the start, it seemed like the game glitched out and started showing me weapon upgrade menus before I had even started the game, and then a bunch more menus popped up and disappeared before I could click on them, and finally after a while I somehow ended up in the actual gameplay part, even though I never actually interacted with the main start menu.
The game itself seems pretty fun, classic arcade action, dodging enemies, collecting healthpacks. I actually liked that the weapons were auto-fire, reducing the cognitive load to just focusing on movement. I would assume the weapons are upgradeable, as well, but I never saw the option to do that come up again after they initially all popped up at once before the game started. Eventually I saw some larger enemies which I thought might be mini-bosses, but they apparently just died with one hit like regular enemies.
Bug fixes aside, the main thing to improve, in my opinion, is to just have more going on with the UI to make it clear to the player what the objectives are and what the end state is that the player is aiming for to complete the game loop. It's possible you actually did have all that in there, but I couldn't get to them with the bugs. Also, maybe allowing the option to use full-screen mode (it's a checkbox on the itch.io project page) would make things nicer on the browser.
Overall, I can see what you were going for, and the artwork is quite nice. With some bugfixing and polishing, this could be a solid game!