I was noticing a similar problem with Boss Rush, and I still haven't figured out why the text just disappears after a certain point. Once I finish up with the character mod that I'm working on, that fix will be my top priority!

As for the lag... Well, yeah. It lags quite a bit when there's a bunch of enemies, and I imagine the effect is way worse in Greed/Greedier Mode. I'll try to optimize the code as best I can on my end, but I think most of the lag is literally just because the game is rendering a bunch of text on-screen, and I can't really fix that besides reducing the max text that can be on-screen. I'll see what I can do, though.

Also, I'm happy to hear that it works well with multiplayer! I don't use controller or have someone online to test multiplayer compatibility with, so it's nice to see that my code actually works with two people.