Drop Duchy is a game that combines elements from Tetris, city-building simulators, and card roguelikes. It involves strategically placing forests, rivers, and plains on the field, constructing production buildings, and building an army to defend territory. Players engage in battles where they must strategically combine allied units and plan attacks based on strengths and weaknesses of different units. The mobile version follows a "try before you buy" model, allowing players to download for free and purchase the full version for 475 rubles.