Very fun and chaotic one! Feels a little unfair at times though, when the balls get behind you or roll on the floor there's just nothing you can do but take a bunch of damage which feels bad. It's also a bit confusing it's best of 5 but 2 wins in row ends it immediately, it would work better with just normal best of 5 or even best of 3 for a match in my opinions. I think if the swinging was a bit more horizontal motion it would feel nicer too. 

I think sometimes the balls went so fast they clipped through the play area as well. And to be honest, the music of the flying boss was kind of irritating, the others were nice! 

I also couldn't go back to the menu if full screened, probably needs a button other than esc for it to work.