Nice art. A very ambitious project for a small jam like this. There are some interesting synergies between cards (e.g., Squire + Knight), though I wished there had been more.
It would have been nice to have some music during the card battles.
Note that I played in fullscreen mode, but a piece of the picture was still cut off; I couldn't see the HUD showing my remaining funds (though I can see from the screenshot where the money display is supposed to be). Also, the indicator showing who's winning the battle could be clearer; I played several battles before I realized what it was.