I do like the animations and the character model, they are pretty slick. The concept of the game is cool, but I think it lacks gameplay. there wasn't much variation in the ball-hitting. maybe having a song to hit the balls on the beat of would have added some nice flavor.
I agree with a few people, there is not enough feedback for hitting the balls. some nice and satisfying sound effect (like the one you get when playing wii sports tennis) would really help. Changing the trajectory of the balls you hit would be some very nice visual feedback too. I would have made it so balls would come at you following a hyperbolic trajectory, to make it more tennis-like.
I couldn't really check the implementation of decentralized technologies, since i'm not so familiar with them.
Congrats on submitting to the game jam!