We got the game and both expansion packs right away. The expansion theoretically can be played on its own, but the black cards are relatively few. We're thinking that as soon as we start to repeat ourselves in the regular game, we'll mix the two expansions, and later all three together, or just start with the black cards from the expansions with the white ones from the regular game.

Unfortunately, if you mix them, there's no way to separate them again, but it probably isn't necessary either.

We want more expansions!! This game is so great that you never get bored no matter how many times you play it (as long as you have good company)! Just be careful, it's the expansion, not the base game!