I love card games, and I was not disappointed. Playing as luck is clever idea and then hoping the player would play the cards right.
But I would maybe double on the luck part, maybe if you have really good result, you could pick some cards for enemy, or maybe show the cards live in battle, so you could be happy that you get this card and not that. Or maybe see all the 5 cards, but you could only select card for the player from the top tree. Because now it still feels too random what you get, even if it isn't random.
But still enjoyed the game, good job.