Gray squares are playable. Hatched squares are islands you haven't reached yet. Score a line of 3 through a warp pipe to jump to the matching color and open that island; each player needs their own line, and more than one player can share a pipe square. A key opens the lock for everyone. A hammer can repair a bombed crater (that uses your turn). When a player has nowhere left to play, squares only another player can still reach are filled in for them and scored. Other items are picked up when you score a line of 3 through their square; until then they show with a dashed outline under your player.