The art is really quite lacking, there's no real theme, and the SFX are sub par.
The gun didn't point in the direction of my cursor which made the gun kind of hard to control.
Shoot to move means when I try to shoot enemies I just fly away from them and can't see them, then they shoot me from off screen which isn't too fun. The only reasonable strategy was to just sit in a corner and shot enemies that come near.
The enemies were just complete bullet sponges, you shoot them a tonne and they just never die, and there's no interesting mechanic to make them better, just point the gun at the enemy and hope it dies before it slowly walks towards you.
you put screen shake on the gun, but it still lacks juice because the sound effect is really not good and there are no good visual effects to go with it.
My score also never went down after I died, which doesn't really make sense.
The player seems to have an invincibility timer after being hit, but there's no indication of when they can or cannot be hit, the player should flash or something when they are invincible.
Keep at it! this will be a good learning experience, and you can improve for next time!