Clones Wars: Video Game Litigation Illustrated

Eric Adler
Oct 22, 2014 · 9 min read

by Eric Adler

Copyright law allows — perhaps even encourages — copying ideas. Ideas are always free to use and modify. What copyright law prohibits is copying the original creative expression of an idea. Since video games are collections of both ideas and expressions, we need to figure out whether the clone copied any “creative expression” from the original game. Some examples might help explain what we mean by separating idea from expression. Let’s start with a case about Atari’s Breakout, and whether it has any protectable “creative expression” at all.

Even Simple Video Games are Copyrightable: Breakout (1992)

Atari, maker of “Breakout” (left) was unhappy with Romstar’s “Arkanoid” game (right). But before Atari could sue for infringement, it needed to register the copyright to Breakout. The Copyright Office initially refused, dismissing Breakout as a mere collection of functional rules applied to basic shapes and colors, and lacking creativity. Atari, feeling insulted, appealed the matter to a young Ruth Bader-Ginsburg (59).

Ruth Bader-Ginsburg appreciated the creativity involved in designing video games. While simple shapes and colors are unprotectable, Atari’s selection and arrangement of simple shapes were copyrightable, especially when paired with creative sound effects. And while game mechanics based on pure physics are public domain, the Breakout game mechanics were governed by creative physics: “The ball’s path in Breakout varies depending on which of four sections of the paddle it hits. Its trajectory does not follow from the laws of physics.” Atari v. Oman (1992). Judge Ginsburg decided that the Copyright Office’s video game philistines didn’t have a “rational basis” to deny Breakout’s copyright registration based on a perceived lack of creativity.

Crazy Kong: Crazy Infringement (1982)

Elcon made a straight-up Donkey Kong clone called “Crazy Kong.” Crazy Kong “embodies audio-video material, including the characters on the screen and the sound, that is virtually identical” to Donkey Kong. Nintendo v. Elcon (1982). Crazy Kong copied every detail of the original Kong, and predictably, got slapped with a rolling barrel of infringement.

K.C. Munchkin: Infringement (1982)

K.C. Munchkin looked a lot like Pac-Man, but it wasn’t an identical copy. This means the judge needed to “filter out” the unprotectable elements before looking for copyright infringement. The judge first filtered out scènes à faire (i.e., stock video game elements):

The maze and scoring table are standard game devices, and the tunnel exits are nothing more than the commonly used “wrap around” concept adapted to a maze-chase game. Similarly, the use of dots provides a means by which a player’s performance can be gauged and rewarded with the appropriate number of points, and by which to inform the player of his or her progress. Given their close connection with the underlying game, K.C. Munchkin’s maze design, scoring table, and “dots” are sufficiently different to preclude a finding of infringement on that basis alone. Atari v. Philips, 672 F.2d 607 (7th Cir. 1982).

The judge then looked at Pac-Man’s “creative expression” — the part of the game protected by copyright. He decided that a maze-chase game “does not dictate the use of a ‘gobbler’ and ‘ghost monsters.’ Those characters are wholly fanciful creations, without reference to the real world.” Atari v. Philips. Finally, comparing only the protectable creative elements, the court found copyright infringement:

The K.C. Munchkin gobbler has several blatantly similar features, including the relative size and shape of the “body,” the V-shaped “mouth,” its distinctive gobbling action (with appropriate sounds), and especially the way in which it disappears upon being captured. An examination of the K.C. Munchkin ghost monsters reveals even more significant visual similarities. In size, shape, and manner of movement, they are virtually identical to their Pac-Man counterparts. K.C. Munchkin’s monsters, for example, exhibit the same peculiar “eye” and “leg” movement. Both games, moreover, express the role reversal and “regeneration” process with such great similarity that an ordinary observer could conclude only that North American copied plaintiffs’ Pac-Man. Atari v. Philips.

Next we’ll compare Pac-Man, a maze game with fictional characters, to a sports game rooted in non-fiction themes and physics.

Karate Champ: No Infringement (1988)

“World Karate Championship” (right) is a clone, more or less, of Data East’s “Karate Champ” (left). The two games have similar graphics and game play. The court first filtered out the elements that were unprotectable under the “merger” rule. Data East could not protect the “idea” of a karate game, nor any game mechanics that necessarily flow from that idea. The unprotectable elements “consist of the game procedure, common karate moves, the idea of background scenes, a time element, a referee and bonus points.” They are unprotectable because “they necessarily follow from the idea of a martial arts karate combat game, or are inseparable from, indispensable to, or even standard treatment of the idea of the karate sport. Data East v. Epyx (1988).

There was no infringement because Epyx only copied the “idea” of a Karate video game, and the non-copyrightable graphics and game mechanics that necessarily flowed from the idea of a karate style fighting game.

Street Fighter II: No Infringement (1994)

After losing the World Karate Championship case, Data East changed it’s stripes. Rather than develop original games, it started cloning games. When Data East cloned Street Fighter II, CapCom cried foul. While Fighter’s History (right) copied most of its details and game play from Street Fighter II, it was careful not to copy the creative game elements. Here’s the judge:

Although Guile and Matlok both have spiky hair and wear similar clothing, they are not identical to one another. Guile is a military figure who wears military garb and has a military base as his home stage. Matlok is a “punkrocker” whose characterization is underscored by his tough appearance and “breakdance” type moves.

Not only did the judge compare the appearance of Guile and Matlock, he compared their magic projectiles:

Their magic projectiles, while similar in appearance, are not identical. In keeping with his personality, Matlok throws a spinning compact disc, the form of which is apparent in some video sequences. Guile, on the other hand, throws a Ch’i mental energy ball and shouts “sonic boom” upon its release. This is in keeping with his military persona.

Some special moves were unprotectable scènes à faire, while other special moves were copyrightable creative expression. According to the court, these 7 moves were not protectable: “(1) Sagat’s ‘tiger knee’ which is a common kickboxing move; (2) E. Honda’s ‘knee bash’ which is a common wrestling move; (3) Vega’s mid-air throw which is a basic fight maneuver; (4) Vega’s floor slide which again is a basic fight maneuver; (5) Balrog’s ‘dashing punch’ which is a simple punch; (6) Zangief’s ‘backwards throw’; and (7) Zangief’s ‘body leap’ both of which are common wrestling moves.” Two special moves were protectable: “Chun Li’s head stomp and E. Honda’s 100 hand slap.”

Since Fighter’s History only copied non-protectable game elements, it was not infringing the Street Fighter II copyright. CapCom v. Data East.

Tetris Infringed by Mino (2012)

Desiree Golden started a video game company called Xio Interactive. Before releasing Mino, a Tetris clone for iOS (right), she carefully researched the applicable copyright law. The judge even acknowledged her research: “Based on this research, Xio believed it could freely copy any part of Tetris that was based on a ‘rule of the game’ or that Xio viewed as being functional to the game.” Tetris v. Xio Interactive (2012).

She understood the gist of the law, but still copied too much. She tried to make a World Karate Champ (copied idea), but ended up with a Crazy Kong (copied expression). The idea of a falling-block puzzle game is not protectable. However, the creative expression of that idea as Tetris is protectable.

The style, design, shape, and movement of the pieces are expression; they are not part of the ideas, rules, or functions of the game. Tetris v. Xio.

Since Mino copied the exact same 7 Tetris shapes, the same board dimensions (10 x 20) and the way the shapes moved through the board, it infringed the Tetris copyright.

Yeti Town: Copyright Infringement (2012)

LolApp cloned Triple Town (left) to make Yeti Town (right). As usual, the copyright analysis starts by filtering out the unprotectable ideas:

The idea underlying Triple Town is that of a hierarchical matching game, one in which players create objects that are higher in the hierarchy by matching three objects that are lower in the hierarchy. Frustrating the player’s efforts are antagonist objects; aiding the player are objects that destroy unwanted or ill-placed objects. Spry Fox’s copyright gives it no monopoly over this idea. Spry Fox v. LolApps (2012).

The court also filtered out unprotectable game mechanics. Using a six-by-six game grid is not an expressive choice. “A grid that is too small would make the game trivial; a grid that is too large would make it pointless.” Similarly, the pricing structure in Triple Town’s marketplace, along with its strategic limits on how many advantages a player can purchase, are functional considerations. Spry Fox v. LolApps.

The court then looked at the remaining protectable game elements, and court decided they were likely infringing. For one thing, “in Triple Town, the antagonist is a bear. In Yeti Town, the antagonist is a yeti… bears and yetis are both wild creatures.” Spry Fox v. LolApps. The judge then compares more specific details:

The object hierarchy is similar. Progressing from grass to bush to tree to hut is similar to progressing from sapling to tree to tent to cabin. Perhaps more importantly, the object hierarchy coupled with the depiction of the field of play comprise a setting and theme that is similar to Triple Town’s. Spry Fox v. LolApps.

The judge also defers to the opinion of video game bloggers: “The bloggers, who are ordinary observers of video games, find Yeti Town and Triple Town to be substantially similar.” Spry Fox v. LolApps. In any event, this case was settled before a final decision was reached. The settlement was confidential, but Yeti Town is no longer available in the app store.


Video game copyright cases turn on whether the clone copied ideas (tolerated) or creative elements (verboten). When looking for similarities between the clone and the original game, we need to mentally “filter out” the unprotectable game elements using several different techniques:

  • Idea-Expression Dichotomy. First we filter out the unprotectable “ideas” from the protectable expression. The idea of a karate style fighting game can’t be copyrighted, but the expression of E. Honda’s “100 hand slap” can be protected by copyright. The idea of a maze-chase game can’t be copyrighted, but the expression of a chomping gobbler antagonized by colorful ghosts (a la Pac Man) can be protected by copyright.
  • Merger Rule. The policy of free ideas is so powerful that if the idea and its expression are inseparable, then the policy favoring free ideas drags both idea and expression into the public domain.
  • Functional Elements. Copyright does not “extend to any idea, procedure, process, system, method of operation…” 17 USC § 102(b). Broadly-defined game mechanics are unprotectable as functional, but more specifically defined game mechanics can be creative expression and therefore copyrigtable.
  • Scènes à Faire. Copyright doesn’t protect cliches, stereotypes, stock elements or standard treatments. For example, Pac-Man’s dots, Street Fighters vitality bar, and zombie-chainsaw-decapitations are all unprotectable scènes à faire. (It’s French for “that which must be done”).

Patents & Technology Law

Practical law for startups, and occasional good news in the fight against patent trolls.

    Eric Adler

    Written by

    Startup and IP Lawyer in Seattle. Also: drones, banjo, bicycles, snacks.

    Patents & Technology Law

    Practical law for startups, and occasional good news in the fight against patent trolls.

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