From one solo dev to another, I must say you are much better at this than me. This is an impressive, polished package for any number of people in the time you were given, and even more so considering you did it yourself.
I think the game loop has the spark of a really neat idea. It reminds me of the Final Fantasy VII Gold Saucer fight minigame, for better or worse. It is rock/paper/scissors, which can be fun, and you added some cool twists to it, but it's still slightly too random for my tastes and I would have preferred some kind of layer of strategy. When it comes to the "healing," I couldn't figure that out at all. It seemed to only work when my opponent healed, which defeats the purpose.
I would be interested to see where you take this. Overall, it is an incredible job, and I quite enjoyed it.