A platform game where the player has to designate certain lemmings for certain tasks & try to figure a way to save as many of them from falling off cliffs and prevent them from dying in other ways. The lemmings can be set for walking (which they do by default), digging, climbing, building, blocking (preventing other lemmings from walking a certain direction), bashing, floating, and mining. There are several levels in 3 or 4 categories of difficulty.
Developed by Psygnosis.
When the Arcade machine was being written, the CEO of Data East apparently wouldn't start a meeting without challenging the person to a 2-player version of lemmings! This is also where the fast forward of Lemmings 2 came from, we saw it in the Arcade version, and borrowed it. Its now very hard to play the original Amiga one without the fast forward. The arcade version was joystick or trackball.
The US cocktail version is slightly different, it has the "Winners Don't Use Drugs" screen.