Try to beat your high score! If you run out of hearts you can either try again at the cost of 200 coins or "Give Up" and submit your score to the leaderboards.
The goal is to figure out how many cards are between the two cards presented. You get coins for answering correctly. You lose hearts for wrong answers. Each correct answer gets you a bar. After 3 bars a correct answer will power you up, clicking on the bars will recover 1/2 a heart.