Someone cloned your game. What the law protects, and what it leaves open.

A game has appeared that plays like yours. Same loop, same structure, a pace you recognise because you spent a year tuning it. None of your files are in it. It still feels like yours.

A game we shipped was extracted, rebuilt and resold. That is a different injury from a clone built from scratch, and the difference decides almost everything that follows. A reused build is a copyright problem with a known procedure. A rebuilt imitation sits on the most argued line in game law. This page sets out where that line is, using the statute, the U.S. Copyright Office and five court rulings on game clones, and then the routes that remain when copyright does not reach. It explains the law as those sources state it. It is not legal advice, and the places where a lawyer earns their fee are marked.

1. First, check whether it is a clone or a copy

The two get mixed together, and they lead to different places. A copy reuses your work: your build, your art files, your audio, your text. A clone is new work made to play like yours.

Look closely before you decide which one you have. Some games sold as "inspired by" turn out to contain the original's files. Signs worth checking:

• An image, sound or line of text that matches yours exactly, not just closely.
• A mistake you made that appears in their game too: a typo, a misaligned sprite, a bug with the same trigger.
• Level layouts that match yours position for position.
• Your store screenshots, trailer footage or capsule art in their listing.

If any of those are present, you have a copy, at least in part, and the takedown process in our guide to a game being sold under someone else's name applies to those parts. Save the evidence the way that page describes before you contact anyone. The rest of this page is about the harder case, where nothing was lifted and everything was imitated.

2. What copyright leaves open

The Copyright Act protects original works of authorship. In the same section it says protection does not extend to any idea, procedure, process, system, or method of operation, however it is described or embodied.

The Copyright Office applies that to games in three sentences. Its page on games says the idea for a game is not protected by copyright, and neither are the name or title or the methods for playing it. It adds that parts of a game may be protected if they contain enough literary or pictorial expression, such as the text of the rules or the art.

So the following are open to anyone, including the studio that just released a game like yours:

• The rules, win conditions and scoring.
• The genre and the core loop.
• Mechanics, however new they were when you invented them.
• Devices that are standard for the kind of game: lives, coins, a score table, a grid.
• Anything the subject or the hardware forces on every game of that type.

This is hard to read when the mechanic was your idea. It is also the rule that let you build in a genre someone else started.

3. Where five courts drew the line

General rules only go so far. These five rulings are the ones lawyers reach for when a game is cloned, and between them they mark the line from both sides. Each links to the opinion.

Read together, they say three things.

A full reskin of the rules is usually lawful. In the Bang! case both sides agreed the rules were nearly identical, and the original still lost, because everything the players could see and read was new.

Copying the look is not excused by calling it a rule. Xio argued that each visual element of Tetris was tied to a rule and therefore free. The court answered that it is not a rule to have a playfield exactly 20 units by 10, and that Xio could have used one "15 units high by 8 units wide" and expressed the same idea in its own way.

Swapping the nouns does not always work. In the Triple Town ruling the judge wrote that a snowfield is not so different from a meadow, and that bears and yetis are both wild creatures. Grass to bush to tree to hut, set against sapling to tree to tent to cabin, was close enough to argue about in court.

4. Your game, element by element

This table sorts the parts of a game by how those sources treat them. It is our reading of the rulings above, laid out the way we would want it on the day we found a clone.

5. Sort what was taken

Before you write to anyone, do on paper what a court would do. It takes an evening and it will tell you which route you have.

1. List every similarity. Play their game next to yours and write each match on its own line. Be specific: "currency is acorns, shown top left, with the same bounce on pickup" is useful, "same economy" is not.
2. Cross out the rules. Anything that describes how the game is played, won or scored comes off the list.
3. Cross out what the genre always has. If most games of your type share it, it is standard.
4. Cross out what the subject or the platform dictates. A karate game has a referee. A phone game has a portrait layout.
5. Look at what is left, and ask one question of each line: how many other ways could they have done this? The Tetris court leaned on the defendant's own expert, who agreed the game could have been designed in an almost unlimited number of ways. Where the alternatives were many and they chose yours, that line counts.
6. Read the remaining lines together. Courts ask whether an ordinary observer would find the two works substantially similar in their protected expression.

Two cautions on reading your own list. First, the comparison rests on what is similar. In the Pac-Man case the defendants offered what the court called a laundry list of differences, and the court still sided with the original, noting that slight differences do not prevent a finding of infringement. Second, there is no percentage. No rule says a game is safe once it is thirty percent different, and no rule says yours is infringed once seventy percent matches.

If the list is empty after step four, copyright is very unlikely to help. If several specific, arbitrary choices survive, take the list and your side-by-side captures to an intellectual property lawyer. This is the point where one is worth paying for, because the same list can be a strong claim or a weak one depending on the court and the details.

6. The routes that are not copyright

The name and the logo

If the clone's title, icon or logo is close enough to yours that players could think it comes from you, that is a trademark question. Federal law gives a claim against a false designation of origin that is likely to cause confusion, and that section does not require a registration. A registration makes the claim easier to prove and easier for a store to act on. The USPTO's base application fee is $350 per class of goods or services.

The test is confusion about who made the game, which is a different test from similarity. The Triple Town judge dismissed the trademark claim as it had been pleaded and observed that a player might see Yeti Town as a knockoff and still recognise that a different company made it. A clone with a clearly different name and icon is usually outside trademark law.

The store's own rules

Stores can remove things the law would allow. Their rules are often the fastest route for a clone that leans on your identity.

• Apple App Store. Guideline 4.1, Copycats, tells developers not to copy a popular app or make minor changes to another app's name or interface and pass it off as their own, and bars using another developer's icon, brand or product name without approval. Guideline 5.2 points owners to the App Store Content Dispute form. Apple says it will contact the other developer and ask them to work with you directly.
• Google Play. The Impersonation policy prohibits apps that mislead users by impersonating another app or developer, and names titles and icons so similar to an existing product that users may be misled. For a trademark complaint, the Intellectual Property policy asks owners to try the developer first and then use Google's trademark form.
• Steam and itch.io. Steam's onboarding rules bar content the publisher does not own or have adequate rights to, and itch.io's terms bar violating copyright, trademark or other intellectual property rights. Neither publishes a rule against games that only play alike.

Notice what these rules have in common. They reach a clone that borrows your name, icon or look. None of them promises to remove a game for sharing your mechanics.

A contract

Think about how the other studio came to know your game. In the Triple Town case, the complaint said the defendant had been given privileged access to the game under a nondisclosure agreement during business talks that fell through. If the cloner was your publisher, porting partner, contractor, former teammate or a company you pitched, an agreement may restrict what they could do with what they saw. That claim does not depend on copyright at all. Find the agreement and show it to a lawyer.

Trade dress

Trade dress is trademark protection for the overall look of a product. Tetris won on it as well as on copyright. To get there the court required that the look had acquired secondary meaning, which means the public had come to associate it with one source, and that it was not functional. Tetris had decades of sales behind it. A game released last month will find that first requirement hard to meet. A lawyer can tell you whether yours is the exception.

Patents

A patent can cover a game mechanic, and a few large publishers hold some. It has to be applied for before the mechanic is public or within a year after, it costs far more than a copyright registration, and it takes years. For a clone that already exists, it is not a route unless you already hold one.

7. Why a copyright takedown is the wrong tool for mechanics

It is tempting to file a copyright notice anyway and let the store sort it out. Please do not. A notice under section 512 includes a statement under penalty of perjury, and subsection (f) makes anyone who knowingly misrepresents that material is infringing liable for the damages and legal fees that result. A notice that says "they copied my mechanic" describes something the Copyright Act says is unprotected.

There is a practical cost too. The other developer can file a counter-notice, the game goes back up unless you sue, and you have spent your credibility with the store's review team on a claim that did not hold. If you later find a real copy, you want that team to take your next notice seriously. The notice process, and what a counter-notice sets in motion, is covered step by step here.

If your list from section 5 has protected expression on it, a notice limited to those specific elements is a different matter. Name them precisely and include the side-by-side images.

8. When the law does not reach it

Many clones are lawful. That does not make the feeling wrong. The makers of Threes published their development emails after their game was imitated. They had worked on it for fourteen months. They wrote that the first clone arrived 21 days after release, that 2048 followed about ten days later, and that it stung to see their own game called a clone of its imitator.

What follows is our view, not law. These are the things an original has that a clone cannot take.

• Be where the players are looking. Clones do best on the platforms and at the prices the original has not reached. The Threes team noted their game was beaten to a different market within six days. If a port or a free version was on your list, the clone has just moved it up.
• Keep a public, dated record. A devlog, a trailer, a store page with a release date. Players and journalists who go looking for which came first should find the answer in one search.
• Say it once, plainly. A short statement that your game is the original and the other is not affiliated with you is fair and useful to players. Stick to facts you can show. Accusing a named studio of theft when the law treats what they did as permitted creates a risk for you.
• Ship the next thing. A clone copies a snapshot. You know why each decision was made and what comes next. They do not.

9. Before the next release

• Put expression on top of your mechanics. The cases reward specific, arbitrary, recognisable choices. Pac-Man's characters were protected because nothing about a maze chase required them. A distinctive cast, world and visual language give you something to stand on that an abstract mechanic never will.
• Register the copyright inside the three-month window. It does not widen what copyright covers. It decides which remedies are open if protected expression is taken. Our registration guide covers the filing.
• Treat the name as an asset. Search the USPTO trademark database before you commit to a title, and consider an application once you have. Reserve the name on the stores you plan to reach, even the ones you will reach later.
• Get an agreement in writing before you share a build. Publishers, porting houses, contractors and co-development partners should each sign something that says what they may do with what they see.
• Keep dated records as you go. Version control history and old builds prove what you made and when, which matters for every route on this page.

Common questions

Can I copyright my game mechanics?

No. The Copyright Office says the idea for a game and the methods for playing it are not protected by copyright. You can protect how you expressed them.

Is it illegal to clone a game?

Rebuilding a game's rules with new art, names, text and code is generally lawful in the United States, as the Bang! ruling shows. Copying the original's specific look, characters or assets can be infringement, as the Tetris and Pac-Man rulings show. Most real clones fall somewhere between, which is why the element-by-element sort matters.

How different does a game have to be?

There is no number. Courts remove the unprotected elements and ask whether what remains is substantially similar to an ordinary observer. A game can share every rule and be fine, or change many details and still infringe because of what it kept.

The clone uses a name almost like mine. Does that change things?

Yes. A confusingly similar name or icon brings in trademark law and the stores' copycat and impersonation rules, which are usually quicker than a copyright dispute. The Triple Town judge also noted that the choice of a similar title could be weighed as evidence of copying.

They copied my game on a platform I am not on. Can they do that?

Your copyright does not depend on which platforms you ship on. If protected expression was copied, it is infringement on any of them. If only the mechanics were copied, it is lawful on all of them.

Does this apply outside the United States?

This page describes United States law. Most countries also separate ideas from expression, but where they draw the line varies, and some have unfair competition laws that reach further than U.S. law does. If the clone's maker or your main market is elsewhere, ask a lawyer in that country.

Should I contact the other developer?

Save your evidence first. After that, a calm, factual message sometimes resolves a name or icon problem in a day, and Google's policy asks trademark owners to try it. Keep it in writing, state what you want changed, and leave out threats you are not ready to carry out.

This page describes United States law and the stores' published policies as of 8 October 2026. The rulings discussed are from different courts and none binds every court; the linked opinions and policies are the authority. It is general information, not legal advice about your situation.