The concept of your game is pretty comparable to mine but totally different. Boxing is a good theme for a one-button game. Adding some exhaustion gauge could be great to avoid infinite attack or guard. A dodge action could be nice too :)
Thanks for your feedback friend.
The energy bar thing is a good idea, because I didn't think about it before XD
Congratulations on your game, I like multiplayer, although I would also like to play with an AI :)