Hardware cloning (1970s–2000s) Cloning of video games came early in the
arcade video game industry shortly after the release of
Pong by
Atari in 1972. Its success led to numerous companies buying a copy of the arcade machine to try to make their own versions. Atari's
Nolan Bushnell called these vendors "jackals", but took no legal action and instead focused on making new games to try to outpace them. Bushnell also maintained contractual agreements with
Bally Manufacturing and
Midway Manufacturing; in the case of Midway, Atari providing Midway with a licensed
Pong design that Midway released as
Winner. The base ideas of a home video game console were developed by
Ralph H. Baer while working at
Sanders Associates, where in 1966 he began work on what ultimately became his "Brown Box" prototype. After securing approval of a proposal for his idea from his superiors, Baer worked with Sanders engineers Bill Harrison and Bill Rusch to execute its design while keeping it within a low cost target. By 1967, the optimized design was ready to be shopped to other manufacturers as Sanders was not in that market area. To protect the idea, Sanders applied for and received three patents in Baer's, Harrison's, and Rusch's names, covering their "television gaming apparatus"; this included the 1974 reissued U.S. Patent RE28,507 for a "television gaming apparatus", U.S. Patent 3,659,285 for a "television gaming apparatus and method", and U.S. Patent 3,728,480 for a "television gaming and training apparatus". Sanders eventually licensed the technology and the patents to
Magnavox, which used it to make the
Magnavox Odyssey, released in 1972. In 1974, Magnavox sued several companies on patent infringement for creating and distributing table-tennis arcade games including Atari and Midway. Atari settled in 1976 and agreed to pay Magnavox for a perpetual license to the three patents and other technology sharing agreements, allowing them to continue to release their home version of
Pong. This case was ultimately decided in Magnavox's favor against the remaining defendants in early 1977. However, just as with the arcade version, the home version of
Pong drew a number of third-party hardware manufacturers to make
Pong clones on the market, to a point where it was estimated that Atari's
Pong console represented only about a third of sales of home
Pong consoles. Magnavox continued to pursue action against these
Pong clones using the three patents, estimated to have won over in damages from suits and settlements through the lifetime of the patents. Threats of lawsuits did not prevent more clones of the home console systems from being built, as these dedicated consoles were relatively risk free and easy to manufacture. This led to a flooded dedicated-game console market, and creating the industry's first market crash in 1977. File:TeleGames-Atari-Pong.png|The original Atari
Pong home console, labeled with
Sears' "Tele-games" brand File:Турнир-Game-Console.jpg|The Russian "Турнир" ("Tournament")
Pong clone File:Magnavox-Odyssey-Console-Set.jpg|The Magnavox Odyssey File:Inter Electrónica S. A. - Overkal.jpg|The Overkal, made by
Inter Electrónica S.A. in 1974, a clone of the Magnavox Odyssey for the Spanish market Eventually, home consoles switched from built-in games to programmable
microprocessor-based systems that operated from software stored in
game cartridges within the
second generation, making it more difficult to clone at the hardware level. However, off-brand manufacturers attempted to make bootleg copies of these consoles that has a similar form as the known console, but typically could only play built in games frequently on a
liquid-crystal display (LCD). Other bootleg consoles would take the workings of older systems and repackage them in a newer housing that appears like the known consoles capable of playing the games from the original system. The latter was particularly true of consoles that attempted to clone the
Nintendo Entertainment System (known as the Famicom system in Japan), which was not available in some countries in the Eastern European and Chinese regions, leading manufacturers within those nations to make
numerous bootleg versions, knowing that it would be near-impossible for Nintendo to seek legal action against them. File:Nintendo-DS-Fat-Blue.jpg|The Nintendo DS File:Neo Double Games.JPG|Neo Double Games, mimicking the design of the DS, but games are played on a
segmented LCD screen File:Nintendo-Super-Famicom-Set-FL.jpg|The Nintendo Super Famicom console File:Pegasus_console%2Bpad%2Bgame.jpg|The
Pegasus, sold only in Eastern European states, was a Famicom clone though styled after the Super Famicom system. Closed consoles were not the only cloned systems. The
ZX Spectrum had been released in the United Kingdom in 1982 and its low cost compared to other home computers helped give birth to the video game sector in the UK as well as Western Europe. The system could not be imported into the
Eastern bloc countries, but enterprising companies found ways to clone the ZX Spectrum hardware at even lower cost. With teenagers and young adults able to afford these hardware clones, they too were able to begin developing their own games and helped to launch the video game industry within these countries.
Early copyright protection (1980s) While hardware itself became difficult to clone, the software of games were subsequently used in unlicensed copies for other systems. Cloning of
arcade video games was popular during the arcade's "
golden age" in the early 1980s. Arcade games, prior to mass production, were made in limited numbers for field testing in public spaces; once news got out that a new arcade game from industry leaders like Atari was out in the open, third-party competitors would be able to scope the game and rush to make a clone of the game, either as a new arcade game or for home consoles; an occurrence which happened with
Missile Command in 1980. This ultimately diluted the market for new arcade games. An early legal question was whether video games were even eligible for intellectual property protection, as both industry and legal experts were unclear on whether copyright law applied. One such game was
Breakout, which inspired many games, including
Arkanoid, which itself inspired many other clones. When Atari decided to register its Copyright in
Breakout,
Register of Copyrights Ralph Oman refused to register the work because it "did not contain at least a minimum amount of original pictorial or graphic authorship, or authorship in sounds". Atari challenged Oman's decision not to award the game copyright protection, and courts sided with Atari that even simple video games could become copyrightable works, as they were both
fixed and original expression. Courts sided with Midway that aspects of an arcade game were copyrightable, even though the images that appeared on the screen were transient.
Stern Electronics, Inc. v. Kaufman similarly decided that the look and feel of a game was fixed, and thus copyrightable, despite differences in the images between different player playthroughs. Thus, it became widely established that video games were eligible for copyright protection, against potentially infringing clones. Clones and variants numbered in the hundreds for
Space Invaders and
Pac-Man, more than a hundred for
Frogger, and dozens for
Donkey Kong. They were programmed by professional and amateur coders for platforms ranging from desktop microcomputers to
graphing calculators.
Nintendo estimated a loss of over to
Donkey Kong clones on various different platforms despite attempts at litigation to stop them; the matter was further complicated by the
Universal City Studios, Inc. v. Nintendo Co., Ltd. case where
Universal Studios who claimed ownership over
King Kong attempted to take action against
Donkey Kong and its clones, notably the
Tiger Electronics handheld electronic game King Kong, but the court ruled in Nintendo's favor along with ordering Tiger to pay damages to Nintendo.
BYTE reported in December 1981 that at least eight clones of
Atari's
arcade game Asteroids existed for personal computers. The magazine stated in December 1982 that that year "few games broke new ground in either design or format ... If the public really likes an idea, it is milked for all it's worth, and numerous clones of a different color soon crowd the shelves. That is, until the public stops buying or something better comes along. Companies who believe that microcomputer games are the
hula hoop of the 1980s only want to play Quick Profit". The degree of cloning was so great that in 1981, Atari warned in full-page advertisements "Piracy: This Game is Over", stating that the company "will protect its rights by vigorously enforcing [its]
copyrights and by taking appropriate action against unauthorized entities who reproduce or adapt substantial copies of ATARI games", like a home-computer clone. In
Atari, Inc. v. Amusement World, Inc. (547 F. Supp. 222, 1982),
Atari sued Amusement World claiming that its video game
Meteors violated their copyright on
Asteroids. The court did find twenty-two similarities between the two games, but ruled against Atari's claims, citing these elements as
scènes à faire for games about shooting at asteroids. Between October 1980 and December 1981, the
Pac-Man game alone generated $150 million in sales.
Philips was one of several developers who attempted to create their own maze game, resulting in
K.C. Munchkin! released in 1981. Courts later barred other clones of Pac-Man, including
Packri-Monster by
Bandai,
Puckman by Artic International, and another similar game called
Mighty Mouth.
Jerry Pournelle wrote in 1984 that "Atari bought itself about a million dollars worth of unfavorable publicity by bullying some very nice teen-aged programmers; surely they could have been smoother about it".
Loosening of protection (1988–2012) The Atari v. Philips decision established that video game clones could be held liable for copying other games, because
K.C. Munchkin! had substantial similarities to
Pac-Man. However, the court also noted that several aspects of the games were standard or common, and thus not protected by copyright. By the late 1980s, courts began to take a more permissive approach with video game clones, deciding that many elements of creativity cannot be protected, such as
generic concepts, functional rules, and
scènes à faire. In 1991, game developer
Capcom released
Street Fighter II. Its popularity led to an explosion of interest in the
fighting game genre. Other companies rushed to capitalize, and
Data East released their own one-on-one fighting game called
''Fighter's History in 1994. As it was later revealed, Data East created design documents that referred to Street Fighter II
several times. Capcom soon sued Data East for copyright infringements, in both America and Japan. Capcom also sought a preliminary injunction to stop Data East from distributing Fighter's History''. Data East used the argument that had previously been used to thwart their 1988 lawsuit against Epyx, that none of the elements that were similar to Capcom's
Street Fighter were protectable under copyright. Capcom U.S.A. lost the case on grounds that the copied elements were excluded from copyright protection, as generic scènes à faire. The case was one of several that made it difficult for a copyright holder to win a lawsuit against an alleged clone, and also allowed game genres to develop based on imitation and iteration. With the costs of filing a lawsuit being very high compared to the expected outcome, many video game copyright holders became hesitant to sue alleged clones. Most lawsuits about alleged clones were settled between the mid-1990s through to the mid-2000s. Some
video game genres are founded by archetypal games of which all subsequent similar games are considered derivatives; notably, early
first-person shooters were often called "
Doom clones", while the success of the open-world formula in
Grand Theft Auto led to the genre of
GTA clones. The genre of
endless runners is based on the success and simplicity of the game
Canabalt. Such cloning can also cause a relatively-sudden emergence of a new genre as developers attempt to capitalize on the interest. The
battle royale genre grew rapidly after the success of ''
PlayerUnknown's Battlegrounds and Fortnite Battle Royale across 2017 and 2018, while Dota Auto Chess'' released in January 2019 spawned several commercial games in the
auto battler genre by mid-2019.
is an open-source clone of the Civilization'' series. Another type of clone arose from developers in the
modding,
open source, and
indie game communities, where these developers seek to recreate the mechanics of a popular title through
reverse engineering, sometimes using their own original assets, and releasing the game typically for free and in homage to the original title. This allows the teams and users to expand upon original elements of the commercial game, such as software bugs that were not fixed, improving gameplay concepts, support for different and newer computers or console platforms, or adding new ideas to the base gameplay principles, as well as easing game extensions through user-created mods or add-ons. Some examples of these clones include
Freeciv based on the
Civilization series,
Osu! based on
Osu! Tatakae! Ouendan, and
Frets on Fire based on
Guitar Hero. The open source nature of these clones also enable new utilities, such as developing
artificial intelligence agents that have learned and improved their play in
Freeciv which in turn can help advance artificial intelligence research. Such games must be careful not to redistribute the original game's assets or they could face legal issues.
OpenSC2K, an open-source recreation of
SimCity 2000, was shut down by
Electronic Arts after it was found that
OpenSC2K used assets from
SimCity 2000. Some projects that started as reverse engineered
game engine recreations, faithful enough to directly use separately acquired assets from the original game by players who own it, may later become game clones by including the original game assets when the rights owners release the game as freeware, as did
OpenRA, a
Command & Conquer: Red Alert clone. It even incorporated code from the original game after Electronic Arts re-licensed it under the
GPL later, as was the case for many game engines in
ScummVM, which subsequently has been used for official re-releases by numerous companies, starting with
Revolution Software's
Sold Out label budget release of
Broken Sword: The Shadow of the Templars. For cloning of original indie games by other indie developers, while such practices do exist, indie developers tend to rely on an informal
code of honor to shun those who do engage in cloning. Clones may also be used as commentary or parody of the original game, usually in a manner considered transformative to qualify as
fair use.
Pyst is a parody of the adventure game
Myst, taking place on seemingly the same island as
Myst but vandalized by numerous groups.
Hatetris became a variant of
Tetris where the next tetranomial provided is the worst possible for the current board.
New developments (2012–present) New concerns related to cloned video games came with the rise of
social network and
mobile games, typically which were offered as
freemium titles to entice new players to play. The rising popularity of these games with casual players led to widespread clones. The game
Mino featured the same approach of using falling
tetromino blocks to form complete lines on a playfield and score points. While there had been many
Tetris clones over the years,
Mino was eventually downloaded more than six million times, culminating in The Tetris Company filing a lawsuit against Xio Interactive in December 2009. Legal and industry experts agreed this signalled that United States courts were becoming more willing to grant broader video games for specific visual arrangements. Though copyright would not limit the imitation of standard game elements, this decision would have the greatest impact on games that copied exact shapes and colors. For example,
Flappy Bird had been cloned dozens of times due to programming code clearinghouses offering templated code to which others could easily add their own art assets. While
2048 had been originally published freely and under an open-source license,
Ketchapp developed an ad-supported version of
2048 that charted on the App Store. Following its sudden rise to popularity at the start of 2022,
Wordle saw a number of clones appear on the App Store in early January, only to be removed in the wake of users criticizing the clone developers. The developers of
Vampire Survivors fast-tracked the development of a mobile port of their game as a response to a number of clones that appeared on mobile app stores with stolen code and assets from the original game;
Vampire Survivors itself was inspired by a mobile game named
Magic Survival. Another major area of concern for software clones arises within China. From 2000 to 2015, the Chinese government had
numerous restrictions on imports of hardware and software, and access to non-Chinese storefronts. While this allowed gaming on personal computers to flourish within China, the cost of acquiring both hardware and software was too expensive for many, leading to Chinese developers to create low-cost clones of popular Western and Japanese titles for the Chinese market, which persist today. Thus, it is common for popular games from both Western and Japanese markets to see near-exact clones appear within China, often within weeks of the original game's release. A notable example is a clone of
Blizzard Entertainment's
Hearthstone called
Sleeping Dragon: Heroes of the Three Kingdoms created by Chinese developer Unico, released within a few months of
Hearthstone beta release. Blizzard was ultimately successful in suing Unico for in damages in 2014. In other cases, clones are made to address elements of the original game that are unsuitable under China's content restriction laws; for example,
Tencent, which operated the publishing of ''
PlayerUnknown's Battlegrounds in China, was forced to pull the game due to content related to violence and terrorism, and instead replaced it with a clone, Game for Peace
, which otherwise reused assets from Battlegrounds'' but removed blood and gore. ==Legal aspects related to clones==