i really like this idea. i been giving a bit of thought. (i don't remember if i read anything for this) you need some kind of card sink, or there will be so many cards they are worthless, i was thinking npc that beats you and takes a card wouldn't really be a good card sink as most ppl would beat npc's with ease, what might work is trading a collection for some items or something special (if you had a card sink idea that i missed, or think its not needed. thats cool it was just an idea) i really hope your game is implemented