This is a lot more fun than I expected.
On gamepad, it looks like super was automatically mapped to RB instead of B for me? The itch page says it should be both. I also couldn't get the back super and curve supers to work.
There were a couple situations in story mode where the AI would get stuck in a loop of trying to tackle the ball. For example, I'd hit the ball straight ahead, and the AI would run up and block, and this would repeat 5 times until I scored. I'm not sure what conditions led to this, because it didn't happen every time.
Overall this is pretty legit; it really feels like a fighting game. Tempted to boot it up again and finish story mode, now that I figured out the basics.