I played local multiplayer against myself keyboard vs controller, I tried to put up a valiant fight against man's strongest opponent (himself).
Only bug I noticed is that I managed to throw my stone outside the ring and was unable to return it.
Aesthetics-wise it reminds me a lot of Blobby Volley, the undisputed champ of local co-op games, which I think works well. Sound effect have a nice comic quality too.