This game was really fun! It felt very mechanically dense for such a simple gameplay loop - It kind of reminded me of smash bros in that regard; easy to pick up, but there's a lot more going on under the surface. I also think the theming is really on point. You seem to know your audience! I think one of the driving forces in my continued enjoyment of the game was getting to see the new challenger characters in the breakneck mode and getting to read their flavor text. It's a fun coat of paint to put on these mechanics.
I think *maybe* an interactive tutorial would be a nice inclusion? The game is pretty easy to pick up once you've played a bit, but I'll be honest, I found my eyes sort of glazing over when I was reading the how to play section. It's definitely easier to learn by playing than by reading. I do think the training mode is a really good addition, but I'd love a short tutorial introduction.
Truly the biggest thing that would prevent me from playing the game is the use of AI art, so knowing that you're in the process of replacing that is great to here. Good stuff!
I played it on stream around 36:30