Hm.... increasing the cooldown for the bigger scales is a nice idea, didn't really think about it...., thanks
Enemies indeed are very weak, but it is that way intentionally, in order to make the player decide if he wants to kill them now (big scale), or later and accumulate score, risking their health later (small scale).
Difficulty indeed is not very balanced yet tho, I'll definitely try to fix it if I make an after-jam version.
Thanks for the feedback!