Thanks for the comment! So, I’m taking note of this criterion for more enemy variety, but for now it’s out of scope (I’m already working on something else, since this project went to a game jam). About the browser, I really DON’T KNOW what’s causing this lag. Yes, The enemies do get deleted when they die. In fact, the Windows version runs on a 2GB RAM PC without any FPS drop. I think GameMaker has issues with HTML5.
If you can, please use the Windows version.
Again, thank you for the feedback!
EDIT: I made a patch, I would appreciate it if you could take a look later to see if it solved the problem.