Here's a much more interesting dev pic:
This is me trying to work out how you will fight battles, what the cards will be how they will integrate, etc.
From this You can probably surmise that there will be a deck of cards, which are dealt out each round. The deck will have battle and shield cards plus one fatal card.
You play a card, they are compared and someone wins the round and someone looses a heart life. continue until one of you is dead - hopefully not you!
This would also mean (much later on) there could be different decks, or deck building?