Heiankyo Alien

Heiankyo Alien

Company type	Video game
Industry	Video games
Founded	1979
Founder	Theoretical Science Group (University of Tokyo)
Headquarters	Japan
Products	Maze video game

, marketed as Digger in North America, is a maze video game created by the Theoretical Science Group (TSG) at the University of Tokyo in 1979. Originally launched as a personal computer title, it was subsequently adapted into an arcade game by Denki Onkyō Corporation and released in November 1979. In 1980, Sega-Gremlin introduced the arcade edition to the North American market, incorporating slight visual modifications.

The title enjoyed commercial acclaim in Japan, securing a position among the top ten highest-earning arcade games in both 1979 and 1980. Since its initial release, it has been adapted for numerous platforms. As an early representative of the maze chase genre, it predates Namco's Pac-Man (1980) and served as a pioneer for a subgenre emphasizing digging holes and ensnaring adversaries, influencing subsequent games such as Space Panic (1980) and Lode Runner (1983).

Gameplay

Players assume the role of a Heian period police officer (), tasked with protecting the capital city () from extraterrestrial invaders by excavating holes to trap them and then refilling these pits to earn points. The faster players refill the holes, the greater their score.

The game comprises nine levels, each escalating in alien quantity. Aliens can escape from holes either over time or if another alien traverses above them. Contact with an alien results in game termination. Each stage includes a time constraint; once expired, alien numbers surge dramatically, rendering level completion nearly unattainable.

After all stages are completed, gameplay cycles back to the initial level. High scores permit players to input their names using a distinctive cursor mechanism where the character walks through letters displayed on the street. A two-player mode is available that supports either alternating turns or simultaneous play.

The arcade version operates on a Zilog Z80 microprocessor and utilizes a system board replicated from Sega's Head On. Due to this duplication, numerous arcade cabinets are essentially "copies of copies," with few original units manufactured by Denki Onkyō still existing.

Development

Heiankyo Alien was produced by the Theoretical Science Group, a team of University of Tokyo students specializing in computer science. Following a decline in the Japanese market after Taito's Space Invaders, Weekly Asahi magazine sought new successful games by visiting computer clubs across Japan. After rejecting several initial proposals, they recognized potential in this group's concept.

The idea originated with Itaru Kawakami, initially involving setting traps for cockroaches but eventually evolving into a Go-inspired board game featuring aliens influenced by the movie Alien. The final setting was established as Heian-kyō, with players embodying a Heian period police officer. This concept was published in Weekly Asahi and first programmed on an Apple II; however, early versions suffered from inefficient optimization and subpar graphics.

Japanese developer Denki Onkyō became interested after reviewing the Apple II prototype and commissioned the group to develop a complete arcade version. Development spanned approximately three months using Z80 assembler language, with iterative testing conducted on ROM boards. Proposed features like a candy power-up were discarded due to complexity; a time limit was introduced to sustain gameplay momentum. The player’s death animation—a floating angel—was added late in development at Denki Onkyō's request. The original subtitle Otoshiana Game ("Pitfall Trap Game") was eventually removed.

Heiankyo Alien premiered at Tokyo's 1979 Amusement Machine Show. A bug was discovered that caused maze sections to vanish if excessive coins were inserted, allowing enemies to escape and leading to data corruption. During playtesting, players reportedly memorized enemy movement patterns. The arcade version launched in Japan in November 1979 alongside a PC edition.

Ports

In 1990, Meldac introduced a Game Boy adaptation in both Japan and North America, featuring a revamped version that included a novel alien species chasing the player. Subsequently, in 1995, Nihon Bussan adapted the game for the Super Famicom under the title Nichibutsu Arcade Classics 2: Heiankyo Alien, building on their previous licensed remake, Kid no Hore Hore Daisakusen. Two additional versions appeared in 2017: NEO Heiankyo Alien by Columbus Circle for the Famicom and an official remastered edition named Heiankyo Alien 3671, launched by Mindware on Steam.

3671 Arcade

Mindware, in collaboration with exA-Arcadia, released an upgraded arcade iteration called Cosmic Digger 3671 in 2021, aimed at audiences beyond Japan. This multiplayer adaptation accommodates up to four players simultaneously and supports both 4:3 and 16:9 display formats, with playfields varying across different stages. Control schemes were enhanced for greater accuracy, and new items were introduced at each level. Players can also select an alternative soundtrack—the Ibojima mix—directly from the title screen.

Reception

Upon release, Heiankyo Alien enjoyed considerable commercial success and was lauded for its innovative design and tactical gameplay. Its popularity was further amplified by the Japanese manga Game Center Arashi, which integrated gaming jargon and player tactics; author Misuru Sugaya has mentioned it as one of his enduring favorites that he continues to play.

Financially, the game ranked within Japan’s top ten highest-earning arcade titles during 1979 and secured seventh place in 1980. Conversely, the Game Boy version received a mixed critical response; a retrospective review from Allgame in 1998 criticized it for lacking long-term engagement and described its concept as monotonous.

Legacy

Multiple arcade variants of the game exist, differing mainly in background colors and sound effects. For example, Taito produced a version featuring a light-blue backdrop that reused numerous audio elements from Head On. This version also came with a distinct cabinet design and instruction card; however, details regarding its licensing remain uncertain. Another adaptation was developed by Hōei Sangyō (currently Banpresto) titled Time Alien, which increased alien movement speed but suffered from input lag during digging or filling actions.

Impact

Heiankyo Alien stands as one of the earliest entries in the maze chase genre, preceding Namco's iconic Pac-Man (1980). It is credited with originating the "trap 'em up" or digging game subgenre, where players bait adversaries into traps dug into the ground. This concept influenced subsequent titles such as Space Panic (1980) and its derivatives like Apple Panic, as well as Lode Runner (1983), which introduced human guards as antagonists. Later examples drawing from this formula include Doraemon Meikyū Daisakusen (1989) and Boomer's Adventure in ASMIK World (1989). Additionally, the VIC-20 cartridge game titled Alien appears to be a direct clone of Heiankyo Alien.

External links

• Official Japanese website
• [1]
• [2]