I noticed something pretty frustrating when I paired this with the Whisper addon. Normally, when Whisper uses her Hammer attack, she goes straight through any enemies in the way. With Chaos Mode loaded, however, she instead bounces off really, really high. This is a notable problem for one reason: Whisper's Hammer is meant to be a grounded AOE attack, and that AOE shockwave only appears once you land. Having what should be a decent AOE attack hindered like this is quite annoying when the whole point of the gamemode is dealing with enemies.
I'm not sure how many other custom characters clash with this addon in as obvious a way as this off the top of my head, but it would be nice if there was some better compatibility here, one way or another.
Aside from that, this is still quite the fun custom gamemode to come back to. Any time I want to see how a custom character deals with a swarm of enemies, this addon is always my first choice to test their combat capabilities.