The idea of copying a successful game concept and profiting off of your own version is practically as old as the game industry itself—just look at the countless Pong clones released in the wake of the Atari original (which itself may have been copied from another source... but that's another story). The idea of game copying has gained added attention in recent weeks, though, as some high-profile social game companies have released games some say are a little too similar to their existing inspirations.

Tiny Tower maker NimbleBit and Bingo Blitz maker Buffalo Studios both took issue with overly familiar titles recently released by Zynga, making their complaints known through large infographics that show near-identical side-by-side screenshots. But Triple Town developer Spry Fox went a step further, actually filing a lawsuit (PDF) against Yeti Town developer 6waves Lolapps, saying the latter company "unabashedly" cloned its popular social game. The lawsuit takes the matter away from the nebulous moral and ethical questions of what constitutes an "original" game idea to the codified legal realm of guilt and innocence. Yet the nature of copyright law as it applies to games, and the existing case law in the area, suggests Spry Fox has an uphill battle in protecting Triple Town in court.

The expression vs. the idea

"Whenever you have a copyright, you're protecting the expression, not the idea," says Mark Methenitis, a Dallas attorney and author of the Law of the Game blog. "It's a line a lot of people have a very hard time with, especially when you get into games."

To explain the difference, Methenitis gave the analogy of a book, where a single word or sentence probably isn't copyrightable, but a paragraph or chapter could probably be protected (and the entire book is obviously protectable). "When you're looking at a game, what's a word versus what's a sentence versus what's a chapter versus what's a whole book?" he asked rhetorically.

Short of cases where one company copies source code wholesale from another game, courts have pretty wide discretion in deciding the answer to that question, and Methenitis says they tend to take an expansive view of what design features are unprotectable portions common to many games. "The elements that get copied over and over and over are almost more elements of the genre, not necessarily stealing from game one to game two, and we've had the copying of mechanics to that degree for years," Methenitis said. In other words, you can't copyright pressing the A button to jump.

How deep can this copying of game design elements legally go? Spry Fox notes in its lawsuit that Yeti Town's gameplay structure mimics that of Triple Town right down to the virtual currency prices charged for similar items. Yet even this might not be enough to prove infringement.

"If it was completely identical—the names were identical, the graphics were almost identical, then maybe... but really it's just one small element of the overall copyrighted work," Methenitis argues. "So you'd say 'Well, maybe the tech tree has the suggestion of infringement, but these other elements are not suggesting infringement based on their differences from the other work.'" Still, he said it will be interesting to see what the court thinks of this similarity.

Where's the actual expression?

A developer's best chance to make a copyright claim against a cloned game comes through the more traditionally creative elements of the game—things like character models, dialogue, or major story elements. But even if those kinds of elements are incredibly similar, it can be very hard to make an infringement case.

Take Fighter's History, a 1993 fighting game that shamelessly mirrored elements of Capcom's Street Fighter II such as character designs, move sets and even the controller motions needed to perform common moves. Capcom sued Data East for copyright infringement in 1994, and while the court found that some of Data East's characters and moves were "substantially similar" to those in Street Fighter II, they weren't quite identical enough to be infringing. Moreover, the court said that Capcom's iconic Street Fighter characters were themselves based on stereotypical characters and fighting techniques that Capcom couldn't lay a copyright claim to.

Simple social and puzzle games are at even more of a disadvantage on this score, Methenitis says, because there's very little creative expression that differentiates the games from one another. "Looking at some of these games, if they had more meat to them, then I think there might be more of a claim because there are more of these things being copied," he said. "But the more simplistic they get... once you've found the few creative elements that exist on top of the social sub-genre, there just isn't that much left that is copyrightable.

"If you went and grabbed Final Fantasy VI and redrew the whole thing, retold the exact same story, tweaked the dialogue a bit with basically all the same characters, that suggests itself to be more like copyright infringement because there are more elements to the work as a whole that are being taken," he added. "[With social games] there isn't a lot of depth to start with, so figuring out where to draw the line on what's the genre and what's the theme, versus what's this game's specific plot, isn't nearly as clear."

Patents and other protections

So is there anything an up-and-coming developer can do to protect its hard work from being outright copied by a larger competitor? One option is filing for a patent, which can be much easier to defend in court if someone infringes on your ideas. In 2004, Sega used a patent it had for the design for Crazy Taxi to successfully sue the makers of The Simpsons: Road Rage for basically throwing the popular animated characters into the same exact game.

But while copyrights are granted to creative works automatically, getting a patent means going through the arduous process of filing with the Patent Office and proving that your work is wholly original. "At this point that would probably mean creating an entirely new social subgenre that wouldn't be invalidated by prior art—the games that are already existing in this space," Methenitis says.

Perhaps a better way for developers to protect themselves from game cloning doesn't involve the legal system at all, but just requires beating the cloners to the punch. "The only way to really stay ahead of this is to be the most innovative kid on the block," Methenitis says. "If you're the one that's constantly coming up with the newer and better ideas, people will play your game and not their game. There's no real way to copy innovation as it happens, you can only do it after the fact, so if you can always stay a step ahead you will have an advantage."