I loved the simple mechanics, perfect example of risk and reward!
I think the shuffle could have some kind of cost, maybe losing a turn, in some challenges I kept re-shuffling to reduce my chances of healing an enemy by mistake so it ended up a bit too easy.
The art style and animation were decent, although I'd love to have clearer feedback from which enemy each attack came.
Overall, great entry! Has a lot of potential for becoming a great strategic game!