Love this! I really like that the game is only as difficult as you make it yourself, if youre careful with shots and aim more precisely the future rounds are less chaotic but on the other hand its way easier to kill enemies by spamming a million bullets in their direction (even if you are literally shooting yourself in the foot by doing so). Having the only enemies be yourself from previous rounds is a great way of implementing the theme and its just such an amazingly genius idea im surprised i dont see it more often.
The controls feel great i especially like that you can shoot bullets out mid-air, i feel like a dodge roll or similair mechanic would fit well in this game to enhance the movement a bit. The art style is very nice looking and the sound design and music is great. I also like the upgrade system a lot, there are so many unique effects that add to the chaos that this game becomes in later rounds. Absolutely amazing job on this game i would love to see it developed further.