Nicely done! Had a blast trying to figure out the puzzles. Just when I thought I had lost, I drew the perfect answer.

Took a bit to figure things out, but once I did it was very satisfying trying to solve the different situations.

I felt like just going all-in and always putting all your cards was the best strategy, which makes the game a bit too easy and not the most strategic. Also having a way to know which card is selected (and to cancel this selection) would be nie.
For the rest the art is nice, and with a few more mechanics (like spells or equipement), you could have a really cool card game :)

This was pretty neat, I enjoyed it! At first I was going to comment that I didn't see much reason not to just play everything as it came up, but then I started hitting the point where I started with less health, and was like "ahhh, I see". Cool stuff!

Cool Concept!

Unfortunately the game seems really unbalanced to me:

There is no incentive to not play all your cards immediately, its quite the opposite since they usually protect yourself with more life than they cost. So it seems to me that the AI is holding back just to let you win. The only thing you are really doing is picking the optimal health/attack card to attack an enemy with a given health/attack.