In Castle Pop, players compete for control of a kingdom’s seven castle towers in a struggle to become the ruler of the realm. Over two rounds, each player secretly places their colored diamonds into the towers, trying to build influence while anticipating where their opponents will play.
On your turn, drop one of your diamonds into one of the three unlocked towers. The unlocked towers are determined by the tower chosen by the previous player, creating a constantly shifting set of choices. Once everyone has placed all available diamonds, the towers are revealed one at a time. The player with the most diamonds in a tower controls it and moves one of their diamonds from that tower into the crown. If players are tied for first place, the player with the second-highest number of diamonds controls the tower instead. If everyone is tied, nobody controls it.
After the first round, players retrieve their remaining diamonds, while the diamonds already in the crown stay hidden. A ring is placed on tower 3, granting a special bonus to whoever controls that tower in the second round. Control of tower 7 also determines who starts the next round and can serve as a tiebreaker at the end of the game.
After two rounds, reveal the crown. The player with the most diamonds in the crown wins and is crowned the grand ruler of Castle Pop. If players are tied, the player who controlled tower 7 in the second round wins; if that does not resolve the tie, the tied players share the victory.