The playfield is a flat grassy plane floating in a void. In the center of the plane stands Ygg, the World Tree. Each player can plant a single acorn. Once their acorn is planted, players must water their tree using a water can in order for it to survive. The trees grow in real time. If a player has extra water, that player can assist another by watering their tree. The World Tree reflects the state of the overall growth. If all player trees die, the World Tree itself dies and the game ends.