In the Castle War Cards game, players use cards to attack the opponent's castle. They can use cards to deal damage to your opponent's castle and gain points. Each card costs a certain amount of Crystals or Bricks to play. Some cards have more powerful effects than others. For example, if you play a Mage, he will grant one extra Crystal per turn. Other cards, such as the Discard Card, allow you to steal 6 resources from your opponent in one turn.
The deck of cards is placed in front of each player. Players then take turns playing cards in increasing order. If a player cannot beat a previous card, they must pick up the entire pile and draw another card from the deck. This process continues until one player has completely cleared the castle. When this is finished, the game ends, and the next player takes his turn.