Moon Patrol

 is a side-scrolling arcade shooter game developed and released by Irem in 1982. It was licensed to Williams for distribution in North America. "Moon Patrol" is often credited with the introduction of parallax scrolling in side-scrolling games. Taito's "Jungle King", a side-scroller released the same month as "Moon Patrol", also uses parallax scrolling.
Gameplay.
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 that travels over the Moon's surface, viewed from the side as it moves toward the right. Craters, mines, and other obstacles on the ground must be shot or jumped over. Two types of flying UFOs attack from above and must be shot down. One of the flying enemies has a weapon which creates a crater when it hits the ground.
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, at 1,000 plus 100 per second bettered; completing an entire course gives an additional 5,000 points plus 100 per second bettered. There are two unique courses: the "Beginner Course" and the "Champion Course". The Champion Course "loops" forever, and each loop is numbered for convenience, up to three. 
Extra lives are given at 10,000 points, and per 20,000 scored up to 50,000; thereafter, no more lives are given. Game ends upon the last patrol car destroyed. The game can be continued, but points scored from one game do not carry over. 999,990 points is the maximum high score that can be achieved; players can exceed this score, if they do, it "turns over".
Ports.
Atari, Inc. released "Moon Patrol" for the Apple II, Atari 8-bit family, Atari 2600, Atari 5200, Atari ST, Commodore 64, VIC-20, IBM PC (as a self-booting disk), and Texas Instruments TI-99/4A. The versions for non-Atari systems were published under the Atarisoft label. The MSX conversion was published by Irem.
Reception.
"Moon Patrol" was among the five top-grossing arcade games on the monthly "RePlay" charts by January 1983.
"Moon Patrol" received a Certificate of Merit in the category of "1984 Best Science Fiction/ Fantasy Video Game" at the 5th annual Arkie Awards. "Arcade Express" reviewed the arcade version in January 1983 and scored it 8 out of 10.
Scott Mace of "InfoWorld" stated that "Moon Patrol" for the Commodore 64 was his favorite Atarisoft game, making good use of the computer's sound. "Computer Games" magazine called the Commodore 64 conversion a "very good" shoot 'em up and the "thinking man's killing game" while noting it has a continue feature like "Vanguard". They later gave the home computer conversions a B- rating.
Legacy.
"Moon Patrol" was included in the retro compilations "Arcade Hits: Moon Patrol & Spy Hunter" for Game Boy Color and "Midway Presents Arcade's Greatest Hits: The Midway Collection 2" for Dreamcast, PlayStation, and Microsoft Windows. In 2006 Bandai released an enhanced version as "Moon Patrol EX" for cell phones. On March 22, 2018, "Moon Patrol" was released for the Nintendo Switch by Hamster as part of the "Arcade Archives" series. A version was announced in 2018 for the Intellivision Amico.
Clones.
A bootleg version called "Moon Ranger" was released in the arcades the same year as "Moon Patrol".
Home clones include "Desert Patrol" for the TRS-80 Color Computer (1983), 
"Gas Hog" for the Atari 2600 (1983),
"Lunar Rover Patrol" for the Dragon 32 (1983),
"Moon Buggy" for the Commodore 64 (1983),
"Moon Alert" for the ZX Spectrum (1984),
"Luna Rover" for the ZX Spectrum (1985),
"Moon Control" for the Amstrad CPC (1985),
"Moonrider" for MSX (1986),
and "Overlander" for the Amiga (1993). "Battle Through Time" (1984) for the Commodore 64 re-themed the gameplay to be about major wars of the 20th century.
Open-source clones named "moon-buggy" and "ASCII Patrol" run in Unix-like terminals.