I like the arcade style of the gameplay, it's really fun! I'm quite impressed you did so many nice gameplay elements in this short amount of time. I'd only suggest you to change that menu selecting sound or turn down its volume a LOT, not sure if it's just me but it's extremely loud and deeply hurts my ears, feels like a stab in my soul. And also changing the button to restart the game on the gameover screen, I was spamming the left click to shoot faster and ended up skipping the gameover screen without seeing my score.
Oh, and I got the bug of the enemies completely disappearing and the red thing stopping in one of my plays, the same others have mentioned. Other than that, I have no complaints. Overall I found it great!