Game Clone Legality
What can you copy?
The legal precedents establishing that game mechanics cannot be copyrighted while specific expressions can, shaped by cases from KC Munchkin to Fighter's History.
Game clone legality encompasses the legal precedents defining what aspects of games can and cannot be protected by copyright. Through multiple lawsuits, courts established that gameplay mechanics are not copyrightable, but specific creative expressions (characters, art, code) are protected.
The British cases, and what they were for
⚠ This entry runs on American precedent alone. In December 1981 Sega brought three actions in the English High Court of Justice under UK copyright law, all over Frogger clones, and won all three:
| Defendant | Clone | Outcome |
|---|---|---|
| Omni Micro Technology (Blackburn) | Leapfrog | “a substantial copy”; seizure orders; written undertakings to the court |
| Computer Video Services | unnamed | successful action |
| London Conversion Company | unnamed | successful action |
Sega “obtained orders to seize infringing goods and documents relating to the title from Omni’s offices”. David Rosen of Sega: “We are particularly pleased with the quick and effective action which has been taken in England to prevent game copying activities.”
And then Omni started selling Frogger legally. Within a month:
Following the lawsuit, Omni appears to have entered into an agreement with Sega Enterprises to properly license and distribute Frogger through their signature Gamepack system, being advertised as early as January 1982 — the following month.
Omni advertised its new licence as a selling point, boasting “the support of the world’s major ‘original’ game manufacturers”. The suit did not remove a competitor; it converted one into a distributor.
Cloning the hardware, not the game
The entry’s precedents are all about what a game is. A different line of cases concerns the machine. In August 1994 Sega sued the Shenzhen-based Shenchu Electronic Equipment Factory in the Shenzhen Intermediate People’s Court over “illegal production and sale of Sega hardware and software”. Shenchu was fined ¥30,000 and ordered “to both cease manufacture of Sega’s products and surrender any existing stock to China’s National Copyright Administration” — and “was found to have directly pirated 15 of the 20 game cartridges it sold”. Console cloning and cartridge piracy as one business.
Fast facts
- Core principle: Mechanics not copyrightable
- Protected: Characters, art, music, code
- Unprotected: Rules, gameplay concepts
- Key era: 1980s-1990s
Landmark Cases
| Case | Year | Outcome |
|---|---|---|
| Atari vs Philips | 1982 | Look and feel protected |
| Data East vs Epyx | 1988 | Gameplay not copyrightable |
| Capcom vs Data East | 1994 | Characters matter, not mechanics |
What’s Protected
| Element | Status |
|---|---|
| Game code | Protected |
| Character designs | Protected |
| Music/art | Protected |
| Story/dialogue | Protected |
| Game title | Trademark protected |
What’s Not Protected
| Element | Status |
|---|---|
| Rules | Not protected |
| Gameplay mechanics | Not protected |
| Genre conventions | Not protected |
| Difficulty curves | Not protected |
The Clone Wars
| Era | Pattern |
|---|---|
| 1970s | Pong clones flourish |
| 1980s | Every hit spawns imitators |
| 1990s | “Doom clones” as genre |
| Present | Mobile clones endemic |
Legacy
These precedents enable genre evolution—without them, one company could own “platformers” or “fighting games.” The balance between protecting creativity and allowing genre development remains contentious, particularly in mobile gaming.