No performance issues on my end except at the very very beginning :D
It was fun leading a big group around then just holding down the special attack and watching them all drop one by one. For multiple levels I spawned right next to the portal. I'm sure that wasn't intentional, but I enjoyed the fast progress I got from it.
I have a couple of questions. How do I get armor? And is there a reason that the max health is 80? Not complaining in any way, you just don't see that very often :)