I'm pretty sure the dealer has the same three cards in his deck as before, and the only significance of a npc having a foil card is that they get to start with it.
curious, can you ever permanently add a foil card to your deck at this stage of the game?
I still think it would be OP. And if your proposing a sandbox mode like that, it should also let you design your opponents deck, as well as not actually letting you play like a true run. (ideally just one combat and then kick you back to the sandbox menu)
