no bad performance of crashes, but i did see some enemies disappear and reappear from time to time.
at first i thought it was some kind of LOD thing, but it also happened when they were close to me
beyond that, LMB LMB LMB LMB, are you going for a risk of rain 2 clone? i imagine it will have power ups and stuff beyond the endless horde of enemies, so it's too early to give proper suggestions