The art is great, I loved the design of the bosses and I liked having to find a way to damage the bosses without something telling me how to do it, it was a lot of fun and intuitive.
I think the mechanic of the card wheel is interesting, because you have to think not only about what cards you carry, but also what order you put them in and how you position yourself with respect to the boss, which I think adds strategy to the combat.
Maybe a little more visual or audio feedback would help when dealing damage to the boss, but it is a very small thing.
I really enjoyed it, very well done! :D