The Map Addition game mechanic is a mechanism in which the game's map is added to as it's explored. In games that use this mechanic, the map starts out incomplete, and players must explore and uncover new areas as they progress through the game.
Examples of games that use the Map Addition mechanic include Mississippi Queen and Eclipse. In Mississippi Queen, players control paddlewheel steamboats and explore the Mississippi River, adding new tiles to the game board as they discover new areas. In Eclipse, players control different alien races and explore space, revealing new tiles that represent planets and other celestial objects.
The Map Addition game mechanic adds a level of excitement and exploration to gameplay, as players must uncover new areas to progress and achieve their goals. It also adds an element of unpredictability, as players never know what they will discover when they explore new areas of the map. Overall, the Map Addition game mechanic is a fun and engaging way to add depth and complexity to board games.