Undergrove is a medium-weight 3X game in which you play a Douglas-fir tree that is building symbiotic relationships with fungi and using them to establish your seedlings. Players explore by adding new mushrooms to a shared forest area, expand by playing new seedlings and roots on those mushrooms, and exploit their relationships with the mushrooms to gain resources. Players then help their seedlings grow into trees by transferring resources through the fungi. At the end of the game, the player who has grown the best set of seedlings with the most valuable symbiotic relationships wins.