Lemmings is divided into a number of levels, grouped into four difficulty categories. Each level begins with one or more trap doors opening from above, releasing a steady line of lemmings who all follow each other. Levels include a variety of obstacles that prevent lemmings from reaching the exit, such as large drops, booby traps and pools of lava. 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. To successfully complete the level, the player must assign specific skills to certain lemmings. Which skills and how many uses of each are available to the player varies from level to level, and the player must assign the skills carefully to successfully guide the lemmings. There are eight skills that can be assigned: 'Climbers' climb vertically though fall down if they hit an overhang. 'Floaters' use a parachute to fall safely from heights. 'Bombers' explode after a five-second timer, destroying themselves and any destructible landscape in close proximity, though not damaging other lemmings or traps. 'Blockers' stand still and prevent other lemmings from passing; lemmings that hit a Blocker simply reverse direction. 'Builders' build a stairway of 12 steps. 'Bashers', 'Miners' and 'Diggers' dig horizontally, diagonally downwards or directly downwards respectively. Lemmings is a very cool SNES game! While the player is able to pause the game to inspect the level and status of the lemmings, skills can only be assigned in real-time. Lemmings are initially released at a rate predetermined by the level (from 1 to 99). The player can increase the rate as desired to a maximum of 99, and later decrease it down to, but not lower than, the initial rate. The player also has the option to "nuke" all the remaining lemmings on the screen, converting them to Bombers. This option can be used to abort a level when in a no-win situation, remove any Blockers that remain after the remaining lemmings have been rescued, or end a level quickly once the required percentage of saved lemmings has been reached. The four difficulty groups – "Fun", "Tricky", "Taxing" and "Mayhem" – are used to organise the levels to reflect their overall difficulty. This rating reflects several factors, including the number of obstacles the player has to surpass, the limitation on the number of types of skills available to assign, the time limit, the minimum rate of lemming release, and the percentage of lemmings that must be saved. Some versions have additional difficulty ratings with more levels in each. More info: Wikipedia