Thanks for playing. I will definitely work on adding some music tracks to the game. I agree currently its too quite :) It would be sick if the soundtrack responded to the actions in game like you described as well.
another question
do you plan to give enemies their effects like how players has one? you could copy paste some of player cards effect to the enemies' cards, but the more fun ideas is to cook up some special or unique effects for them. something like how if the king dies then the queen will double attack or something like that
by doing this it would give the players some real challenges and may push for different rewards picks (because everytime rewards comes up i always choose extra card slot because it is simply that powerful)