As with the original Tiny Combat Arena, this little mini-game has been unlisted for the time being. I keep seeing chatter around this demo as if it is representative of the final game and it simply isn't at all. They are quite literally different games.
That said, I do plan on making this available again at a later time, or if I can figure out some better way to distribute it while still making it very clear that it's not the same thing as the game on Steam.