Oh, it is indeed missing a tutorial in it on how to play. Essentially, each player must discard a number of cards matching the current value indicated in the middle. You can lie, but if you get caught, you buy the same number of cards and give a biscuit to your opponent. If you're falsely accused, you win your opponent's biscuit. With you get 0 biscuits, you lose. If you get 0 cards in hand, you win. Thanks for the feedback!