Keyper is a worker placement game. (Keyper is the eighth new title in the medieval Key series of games, with Keydom, the second in the series being widely recognized as the first of the worker placement genre of games.) What makes Keyper special is that when one player places a keyple on a country board, another player can join them with a matching colored keyple on the first player's turn to the benefit of both players. In this way some players are likely to have played all their keyples before others. All keyples have the potential to work twice. If a player has played all of their keyples, but another player still has some, then on their turn the player with no remaining keyples can lay down one or more keyples on the country board they have claimed or in their village board to secure additional resources or actions. It can therefore be doubly beneficial to co-operate with your fellow players, although Keyper is not a co-operative game in the usual sense of the term.