Out on a LEM is a BASIC-programmed Lunar Lander -type game. The goal is to land on the white goal pad without crashing into moon's jagged surface. The cursor keys are used to operate the left, right and vertical thrusters to land the Lunar Excursion Module (LEM) as gently as possible. A thruster is turned off by pressing the same key a second time. The fuel supply also needs to be watched. If there is fuel left, the on-board computer will attempt to return the LEM to Earth.