The goal is to guide at least a certain percentage of the green-haired, blue-robed lemmings from the entrance to the exit by clearing or creating a safe passage through the landscape for the lemmings to use. Unless assigned a special task, each lemming will walk in one direction ignoring any other lemming in its way (except Blockers), falling off any edges and turning around if they hit an obstacle they cannot pass. A lemming can die in a number of ways: falling from a great height, falling into water or lava, disappearing off the top, bottom or side of the level map, being caught in a trap or fire, or being assigned the Bomber skill. Every level has a time limit; if the clock counts down to zero, the level automatically ends.