Each game in the Lemmings series consists of multiple levels, each requiring the player to rescue a pre-defined number of the green-haired blue-shirted lemmings by guiding them to the exit. Played in real-time, at the start of each level lemmings start to pour through the entrance point - their movements tend to be linear, continuing to walk in a predefined direction until reaching a blockage or peril. Various perilous locations tend to the litter the levels, and the player must guide the lemmings around them or risk lemmings walking to their death. This is accomplished by assigning individual lemmings particular roles (ramp builder, digger, climber, etc.) in order to bypass the particular problem. With a pre-defined limit on job allocations, and with later lemmings invariably not waiting for their associates to complete their jobs before continuing on their way, the games tend to involve hectic job-allocations in order to meet the required targets for level completion.