Alrighty, here's the bugs I've discovered thus far:

[Ruby on Ruby's Endless Map] On a higher round, I sliced through like 15 enemies at once with Ruby's jump dash (not an exaggeration), the music completely cut out for a moment, and then the game was like this (see below video). I couldn't interact with any of them, so I eventually had to just restart.

[Ruby on Ruby's Endless Map] I was able to (unintentionally) make it happen again at a higher round, at which point the enemies acted a little differently this time, but still soft-locked the game (see video below). This time I didn't hit several enemies to cause it happen, I only hit a few with Ruby's jump dash (it's my go-to move, lol), and one of the enemies was still alive at 0HP when the bug started, so it might be related to that. HOWEVER, I had the game running for a while in the background and when I opened it back up, I was back at round 1! So I think it eventually un-soft-locked itself in some way and I died unknowingly while it was running in the background. Which might be relevant to my next point.

[Ruby on Ruby's Endless Map] There were a lot of enemies I was fighting at once, often hitting several of them at one time. At one point, there were some normal beowulves that were at 1HP that walked casually out of the map where I couldn't reach them, even to the point where I couldn't see them. I waited around towards the center and they eventually showed up, though from a different direction than the one they walked offscreen towards. I thought there were only like two or three that walked off stage, but one at a time there was like eight 1HP beowulves that showed up and then there were two 3HP ones (still only one at a time) and then the round ended and things continued normally. So it's possible that if I wait long enough or something, these glitched out enemies fix themselves.

[Blake's Endless Map] Also, I tried Blake's endless map with both Ruby and Blake, and on both characters, when the round reaches round 6, it repeatedly waits a few seconds and increases the round number; it wasn't spawning any enemies for any of the rounds.

Also, both of the videos I posted have the game screen cut off, but that's just a recording issue on my part; the game looks fine when I play it. :)

I really love the game and have had a blast playing it, these bugs have been fun to find. :P