Presentantion is Ace and Jack out of 21, no questions there.
While main battle mechanic is neat, battles aren't really different from one another. There were one creative moment with Crazy Eights during final battle, where you could kill them until you've got 21 instead of facing Jack every attack, and that was cool, and more strategic moments like this would make the game so much better,
Overall, good jam entry with great presentaion and underwhelming gameplay.