* Some of the cards have red backs. If you are only looking at the faces of the cards, you may not notice this, as the faces on the red-backed cards look just like their blue-backed counterparts. Do not mix the red ones in with the others! In fact, set them aside entirely, you do not need them at all for your first game.
Well you may not "need" them for your first game, but they are there to be placed at the bottom of each stack to indicate when you've bought out a green or red card stack (except Merch and Fleshreaper).