No speaker issues (as warned by the description) for me, the sound of shots connecting (especially as the fire rate increased) was extremely satisfying!
One point I'd raise is enemy spawn locations - while some would emerge from out of bounds/off screen, giving me plenty of time to react, others would pop into existence right next to me. This was much more an issue in the late game, where I would be trying to clear pockets of space to move into and suddenly and enemy would spawn and damage me before I could react.
Really enjoyed the game, impressed by what you could come up with in 3 hours!