I thought this game was super fun and I really enjoyed the idea of improving both yourself and the enemies as you went. I stopped playing after round 20 because the rounds started to feel a little repetitive and not terribly challenging, but that is just my personal opinion so you didn't lose any points from me there. I occasionally encountered a minor bug where one of the enemies would get into the top wall area and my bullets wouldn't reach them. My only major gripe was the hit/kill effect on the screen. Personally, I thought it was cool but a little too strong especially in the later levels when you have more bullets and enemies. It was a bit disorienting and I often lost track of the player character.
All in all I enjoyed the game and will probably play it again. Thank you for making it and thank you for putting it our here so I could enjoy it!