The outer pathway of the top layer offers the greatest advantage in the stage. While the platform in the middle of the top layer is wider, it is not in the best location for attacking. Players on the outer pathway are in a good position to throw and kick bombs down at players who are in the lower layers.
However, multiple players may vie for a position at the top. If this happens, a player may choose to trap his or her opponents, forcing them to retreat to a lower layer and putting them at a disadvantage. Two players may work together to force a third player down, for example, by kicking bombs at the opponent from opposite sides.When Sudden Death begins, the water will begin to rise, slowly submerging the stage.
Baku Bomberman Official Guidebook, pg. 99