Thank you! I'm glad you enjoyed it.
Splitting "attack" into two stats was originally motivated by an attempt to make the game's core nonviolent - the score stat was first. But by the time I tried to come up with a way to interact with the opponent's board, combat turned out to be the most elegant solution anyway! So both mechanics made it in.
Basing play cost and card play limit based on hand size was an attempt to simplify the game so that hand size was the only resource - I'm glad it worked!