I have a suggestion, when you open the upgrade center, it would be super helpful if you paused the game. That way people have a sense of progression without instantly dying. eventually, by around wave 24, your upgrades become obsolete. I think that you should change the way that you do upgrades, so that the gun can be infinitely upgradeable. I am a gamedev myself and could suggest a few ways to implement this.
hope you like the feedback, you are more talented than most and are way too underrated - keep up the good work! I hope you grow your channel larger!
