Centipede

Centipede
Title	Centipede
Release date(s)	1981
Original Platform(s)	Arcade Machine
Original Publisher(s)	Atari
Developer(s)	Ed Logg Dona Bailey
Category(s)	Entertainment Arcade

History of Centipede

Centipede was one of the defining arcade games of Atari's golden age and one of the company’s most successful attempts to move beyond the space-themed shooters that had dominated the first years of the video game industry. Released by Atari in June 1981, the colorful trackball-controlled shooter was created primarily by veteran game designer Ed Logg and programmer and designer Dona Bailey. Its combination of simple controls, rapidly changing play conditions, distinctive pastel-colored graphics, and an unusual cast of insects made Centipede immediately recognizable in an arcade crowded with spaceships, aliens, tanks, and missiles.

The game also occupies an important place in video game history because of Bailey’s role in its creation. When she joined Atari's coin-operated games division in 1980, she was its only female software engineer. Working with Logg, she helped transform a very simple concept—shooting the segments of a crawling insect—into one of Atari’s most enduring games.

Origins

The idea that eventually became Centipede originated in Atari's internal brainstorming process. Atari periodically collected possible game concepts, many of them only a sentence or two long, for designers and programmers to develop.

Bailey later recalled looking through a notebook containing roughly 30 possible concepts. Most involved familiar themes such as spaceships, lasers, aircraft, or warfare. One proposal, however, described a multi-segmented insect crawling onto the screen and being shot piece by piece. Bailey was attracted to the idea partly because it was different from the military and science-fiction concepts surrounding it. As she later explained, shooting a bug seemed less violent than shooting people or spacecraft.

Bailey had arrived at Atari by an unusual route. Before entering the video game business, she worked at General Motors' Delco division in California, programming assembly-language microprocessors used in automobile systems. Her interest in video games began after a friend introduced her to Space Invaders. Bailey recognized that the game's display was being controlled by technology similar to the microprocessor systems with which she was already familiar. After learning that Atari used the MOS Technology 6502 processor, which she knew how to program, she pursued a position with the company.

Atari paired Bailey with Ed Logg, already an accomplished game designer whose credits included work on Super Breakout and the enormously successful Asteroids. Logg took the lead on much of the game's design, while Bailey performed a substantial portion of the programming and contributed to its visual appearance and gameplay. Logg later estimated that Bailey wrote approximately half of the game's program code.

Development began during the summer of 1980. Bailey recalled that Centipede was developed from approximately July 1980 until it entered production in May 1981.

Building the Game

The basic concept was simple. A centipede would enter at the top of a vertical screen and travel horizontally through a field of mushrooms. When it encountered a mushroom or the edge of the screen, it would descend one row and reverse direction. The player, controlling a small "bug blaster" near the bottom of the screen, attempted to destroy the creature before it reached the player.

That simple idea produced an unexpectedly sophisticated playfield.

Shooting a segment of the centipede caused the destroyed segment to become a mushroom. If a middle segment was destroyed, the remaining portion could split into another independently moving centipede. The player's actions therefore continually changed the environment. Shooting the centipede made progress toward completing a wave, but simultaneously created additional mushrooms that could alter the paths taken by later enemies.

The mushrooms themselves became one of the most important elements in the design. According to Logg, they were initially static obstacles. During an Atari design review, engineering manager Dan Van Elderen asked why the player could not shoot them. Allowing the mushrooms to be damaged and destroyed became an important breakthrough because it gave players another way to reshape the battlefield.

Logg then faced another problem: if players could destroy mushrooms, the game needed a way to replenish them. One solution was to leave a mushroom behind whenever a centipede segment was destroyed. Another was the flea, which occasionally dropped vertically through the screen while leaving new mushrooms behind. This ensured that the mushroom arrangement would not simply become a pattern entirely determined by the player.

Other creatures introduced different threats.

A spider bounced unpredictably through the player's portion of the screen, forcing the player to remain in motion while also consuming mushrooms. Bailey worked extensively on the spider's movement and later remembered experimenting with several unsatisfactory patterns before settling on its characteristic bouncing motion.

A scorpion traveled horizontally across the screen and poisoned mushrooms. When the centipede encountered a poisoned mushroom, it began plunging toward the bottom of the screen, greatly increasing the danger to the player. Atari's own 1981 description emphasized how these interacting enemies caused the game continually to change as the player became more proficient.

The result was a game in which the playfield was never entirely predictable. The mushrooms accumulated and disappeared, the centipede divided into separate pieces, fleas repopulated the field, spiders invaded the player's territory, and poisoned mushrooms could suddenly send the centipede diving toward the bottom of the screen.

The Trackball

One of Centipede's most distinctive features was its trackball controller. Instead of moving only left and right along the bottom of the screen, the player could move freely within a limited area covering approximately the lower portion of the playfield. Rapidly spinning the trackball allowed the bug blaster to dart away from enemies with a responsiveness difficult to duplicate with an ordinary joystick.

There are slightly differing recollections concerning when the trackball entered the design.

Logg later remembered the trackball being used from the beginning, noting that he already had experience with trackball controls from Atari's Football. He considered it especially well suited to Centipede because it allowed both direction and speed to be conveyed naturally.

Bailey remembered the process differently. She recalled that the game was tried with other control arrangements, including a joystick, and that she strongly preferred a simple, natural control system rather than numerous buttons. She said the trackball proved far more comfortable and intuitive and ultimately became the production control.

Whatever the exact development sequence, the trackball became inseparable from the arcade version of Centipede. Combined with a single fire button, it produced an unusually accessible control scheme: a new player could understand the fundamentals almost immediately, while skilled players could develop extremely precise movement.

A Different Look for the Arcade

Centipede also looked strikingly different from many contemporary arcade games.

Bailey took a particular interest in its color palette. She later recalled that the game initially had a much more limited appearance and that she pushed for brighter and more varied colors. During experimentation with the game's display hardware, a technician adjusting the color circuitry produced an unusual combination that Bailey immediately liked. She continued experimenting with the palette, ultimately helping give Centipede its distinctive mixture of vivid and pastel colors.

Against the dark environment of an early-1980s arcade, the pinks, blues, greens, purples, yellows, mushrooms, and animated insects gave the cabinet an appearance unlike the stark space imagery associated with games such as Asteroids, Space Invaders, or Defender.

Bailey later rejected the simplified story that Centipede had deliberately been designed as a "game for women." Her stated goal was broader: she wanted the game to look attractive, to be easy to control, and to appeal to anyone who encountered it. She did, however, hope that its familiar creatures, bright appearance, and approachable trackball control would distinguish it from the predominantly space- and combat-oriented games surrounding it.

The resulting game did become notable for attracting a broader audience than many contemporary arcade shooters, and its association with female players became part of its historical reputation.

Testing and Release

As development progressed, Centipede went through Atari's usual internal review and testing process. Employees played prototypes and offered suggestions, followed by more formal marketing evaluation and field testing. Bailey recalled that Atari conducted a focus group and then placed the game in a Mountain View, California arcade for several weeks to observe how actual customers responded.

The game entered production in May 1981. Atari offered Centipede in upright, compact "Cabaret," and cocktail-table configurations. The arcade hardware was built around a MOS 6502 microprocessor, with an Atari POKEY chip providing sound. The production game used a vertically oriented color raster display and its now-famous optical trackball.

Atari promoted the game aggressively. A June 1981 issue of the company's Atari Coin Connection trade newsletter described Centipede as a game whose difficulty continually changed as additional creatures appeared and the action accelerated. Atari even offered arcade operators a promotional kit containing posters, T-shirts, advertising material, radio scripts, contest ideas, and other items intended to help publicize the machine.

The company also selected Centipede as the official tournament game for its $50,000 Atari World Championships held in Chicago from October 29 through November 1, 1981, further demonstrating how quickly Atari had come to regard it as one of its major titles.

Gameplay and Lasting Appeal

A major strength of Centipede was that its rules generated increasingly complex situations without requiring a complicated explanation.

Destroying a centipede segment could make the immediate threat smaller but also create another mushroom. Mushrooms redirected later centipedes. Fleas created still more mushrooms. Scorpions poisoned them. Spiders forced players away from comfortable firing positions. As the game accelerated, these independent systems began interacting in ways that made each play session slightly different.

The player was therefore doing more than simply shooting targets. Skilled play involved managing the mushroom field, anticipating the centipede's route, deciding when to clear mushrooms near the bottom of the screen, avoiding the spider, and reacting rapidly when poisoned centipedes began descending directly toward the player.

Logg later attributed much of the game's balance to extensive tuning of the timing and speed of its different elements. A planned grasshopper enemy was never needed because the spider already accomplished its intended purpose of forcing the player to move. Interestingly, graphics for the unused grasshopper remained hidden within the game's diagnostic graphics.

Centipede Comes Home

The arcade game's popularity made Centipede an obvious candidate for Atari's home systems.

Versions eventually appeared for the Atari 2600, Atari 5200, and Atari 400/800 computers, along with versions for other contemporary systems. Each conversion faced the difficult problem of translating a game designed around a vertically oriented arcade monitor and precision trackball to home machines normally controlled by joysticks.

The Atari 5200 version was particularly well suited to reproducing the arcade experience because Atari offered a separate Trak-Ball controller for the system. Atari's marketing material described the 5200 edition as closely resembling the coin-operated game and specifically promoted compatibility with the CX53 Trak-Ball controller. The 5200 cartridge was released in February 1983.

The home conversions helped keep Centipede visible long after its initial arcade success and introduced the game to players who had never encountered the original cabinet.

Millipede and Later History

Atari followed Centipede with Millipede in 1982. Again designed by Ed Logg, the sequel retained the basic insect-shooting concept while introducing additional enemies, more complex attack patterns, and other refinements intended to challenge experienced Centipede players. Millipede never eclipsed its predecessor's cultural recognition, but it demonstrated how durable the underlying design had become.

Centipede itself subsequently appeared in numerous compilations, remakes, licensed adaptations, and retro-game collections. Its basic design also inspired a large number of unofficial imitations on home computers during the early 1980s.

The original arcade game remains immediately identifiable more than four decades later. The descending segmented centipede, mushroom-filled playfield, bouncing spider, chirping sound effects, pastel colors, and rapid movement of the trackball produced a combination unlike almost anything else in the arcades of 1981.

It also represents an important moment in Atari's development culture. Ed Logg brought to the project the game-design experience that had already helped produce Asteroids, while Dona Bailey brought a different programming background and aesthetic sensibility to Atari's largely male coin-operated engineering department. Their collaboration transformed a brainstorming note about shooting a segmented insect into one of the best-known video games of the early 1980s.

For Bailey, Centipede would remain her principal contribution to commercial video games. She began another Atari project, Weather War, but left the company before completing it. Her relatively short career in the industry nevertheless produced one of its enduring classics.

For Atari, Centipede joined Pong, Breakout, Asteroids, Missile Command, and Tempest among the games that defined the company's early arcade legacy. More importantly, it demonstrated that an arcade action game did not need spaceships, military hardware, or alien invaders to create tension. A garden full of mushrooms and insects—and one exceptionally well-designed trackball was more than enough.

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