Wow! I think it's pretty awesome that we both got to a similar game! The biggest issue with my game is handling bullet spawns because when you kill around 50~ enemies the bullet spawn just gets so fast that at least my computer can't handle it. I tried implementing a premade pooling system today and while it did help a a bit (before it the game was playable till around 20 enemies for me), it didn't solve the issue.
I agree that reducing the amount of enemies you can kill with one bullet would lower the chances of crashing, however I feel like "golfing" the bullet is a fun mechanic (I had it limited to 1 enemy at first).
Thanks for the advice tho!