It's impossible not to just echo what Bworg has already said. This is great. Really great. I would pay for a full game of this. Great visual, audio, and mechanics design. Great writing. I wish I had made it :P
In the interest of giving some kind of constructive criticism, the only thing I can think of, which I am sure you already know is, it would be nice to have a few more UI bells and whistles (e.g., a border showing which character card I have selected).