Lunar Leeper

In this game, you must guide your spaceship around while picking up hostages
located on the surface, and bring them to safety. Your task becomes difficult
by lunar leepers who leap up and try to grab you or the hostages that are
picked up by your ship.

If you approach a hostage while a leeper is nearby, the leeper will keep
walking toward them until they are killed. If you are grabbed by a leeper, you
lose a life. You can shoot at the leepers, but the catch is that you cannot
shoot at them while they are on the surface, and you have limited ammo. You
also have limited fuel, and if you are half-empty, you must refill at the gas
depot in order to continue.

In between levels, you enter a cavern where you must find a huge floating
object. You must then shoot out its core to proceed to the next difficult
level.