Um, so I may or may not have found a bug lol
Got to Round 23 at ~4-5 minutes and all the enemies just stopped spawning. So I ran the game at 500x speed to see if the enemies are truly never going to spawn and might have set a world record on the game in the process lol
EDIT: So just tested hitting the "skip round" button a bunch of times and that doesn't do anything either, still no enemies.