Islets Defense combines turn-based defense with settlement building, where the goal is to build a village to support the castle. Every action taken, from constructing a structure to collecting materials, brings enemy waves closer to the fortifications. A turn consists of choosing one of four cards, which determines the operation to be performed. The position of these cards changes their effect: the rightmost one provides a stronger result, after which it ends up on the left edge of the deck, which requires planning the sequence of moves.