To turn a card over, click it. You must uncover all the 2's and 3's. If you uncover a Voltorb, it's game over. If you win, your coins will be carried over to the next game, so you can continue and try for a super high score. When you find a number greater than 1, it will be added to your score. To mark a card for that round (i.e. if you know it's a Voltorb you can mark it with a 0), hover the mouse over the card you want to mark and press 0, 1, 2 or 3 to mark that number. 4 marks 0 1.
