Moon Patrol (ムーンパトロール Mūn Patorōru) is an arcade game by Irem that was first released in 1982. It was licensed to Williams for distribution in North America.
Moon Patrol was an early side-scrolling shooter and is widely credited for the introduction of parallax scrolling in side-scrolling video games (though one article in Games Radar argues that the graphics in the 1980 game Defender would count).
The player takes the role of a Luna City police officer assigned to Sector Nine, the home of the "toughest thugs in the galaxy". The player controls a moon buggy, viewing it from the side, that travels over the moon's surface. While driving it, obstacles such as craters and mines must be avoided, and various enemies such as UFOs from above and tanks on the ground must be shot down.
Gameplay is within a number of "courses", and each is divided into 26 checkpoints, named after the letters of the English alphabet. Of these, the five major checkpoints--E, J, O, T and, Z--denote a new "stage" with a new background and theme; for example, the third stage starting at J introduces mines. The top portion of the screen shows a timeline-style map of the course, with the five major checkpoints clearly marked. Above the map is an indicator of the current checkpoint, the time spent in the stage, and three indicator lights: the top light indicates upcoming enemy aerial attacks, the middle one indicates an upcoming minefield, and the bottom one indicates enemies approaching from behind.
At the end of a stage, that time spent is compared to the average, and bonus points are awarded accordingly; completing an entire course gives an additional 5000 points. There are two unique courses: the "Beginner Course" and the "Champion Course". The Champion Course "loops" forever, and each loop is numbered for convenience.