Very original game! I haven't seen any game like this one. Fits the game perfectly, spawn hint, text animations, special enemy movement, fantastic pixel art, All of these make the game a fantastic experience. This game kinda reminds me of GMTK roles reversed theme. Well done!! I hadn't reached to your skill level yet. So I can't give any useful tips. Sorry. Of course I think you can add some sort of mutation upgrades. Maybe some increased speed or dash ability or the mutation "ring" appears faster or you get more health as bubble. Some smarter enemies must be also cool in the mutation mode. Sorry those were the only ideas that I could think of.