Disclosure: The organizers of the Power of Play event paid my way to Seattle, where I’m moderating a session. Our coverage remains objective.

SEATTLE — When Daniel Cook changed the range of a bullet from 6.5 tiles to 5.5 tiles in his game Realm of the Mad God, fans were outraged. They whined, protested, and raged.

So much for of the power of a game designer to control a game.

Cook, who spoke at the Power of Play game conference in Seattle, said that the online “bullet hell” title Realm of the Mad God had millions of downloads and minimal multiplayer online features. But he was surprised to the extent that players created their own hierarchies, rules, and even governments inside the game. This phenomenon, known as emergent behavior, helped propel the game to millions of downloads and sprout a real fan community.

Image Credit: Dean Takahashi

“As the game designer, you are the god,” said Cook, a designer of games such as Triple Town at Seattle-based game studio Spry Fox. “But no one told you that you can’t use that power.”

Cook offered advice to indie game designers who don’t have huge budgets but still have as good as shot as anyone else at creating a game that fans will make into their own. This kind of game has some huge successes, such as user-generated content games like Minecraft, as well as giant failures like the moribund Sims Online.

“My goal is efficient design, as I work with tiny teams,” he said. “When I get a huge amount of emergence from a small amount of gameplay and game design, I am excited.”

Realm of the Mad God has the rudimentary features for emergence, including communication. It’s also a fun game, with a nostalgic 8-bit style graphics and a simple goal of shooting as many things as you can. It followed the simple rule of gaming economist Edward Castronovo, who observed that if a group of players is more efficient than a lone player, the players will then gravitate toward group play. In Realm of the Mad God, players gang up on artificial intelligence boss characters.

“We had an explosion of government, with groups, hierarchies, laws, punishments, politics, propaganda, power plays, and rebellions,” Cook said. “It was not something I saw in simplistic games, as this is barely a massively multiplayer online game. Once you have this emergence, fans create their own content. And there are millions of them.”

When fans create their own stuff, the developer can jump off the content treadmill, where they have to constantly create new material for the die-hard fans who have consumed all of the content already.

“If you set up a game where groups are more efficient, you will get emergence,” Cook said.

The downside of emergence is chaos. You can see a real Lord of the Flies-style behavior, a reference to the landmark book where a group of boys, stranded on a deserted island, do horrifying things to each other in the name of survival. That’s what happened in Electronic Arts’ The Sims Online, which had a utopian setting but turned into a hell where players created organized crime groups and punished new players by locking them in bathrooms until they died. EA had no way to punish players who did such things.

“We’ve seen the formation of mafia, subversive systems, corruption, giant protection schemes, griefing, and vigilantism,” Cook said. “If you want to see how fast a moral person turns into the biggest scumbag on earth, all you have to do is give them mod privileges” that enable them to modify and create things in an online game.

You can also see emergent good behavior, like the healers who roam across the zombie-killing game DayZ, healing other players. Other groups protect newbies from veteran player killers.

Emergence also happens when you have scarce goods that players can collect, modify, or trade. You can also support the creation of clans, or groups of players. But groups with more than 80 are hard to hold together because they’re too big for players to form bonds of friendship with everyone. In large groups, you need formal rules.

To prevent bad behavior, you have to enforce some rules of behavior by building it into the design of the game. Some companies like CCP (the publisher of Eve Online, the space-based MMO with a Wild West reputation) have deliberately encouraged emergent behavior with crafting and trading systems, where players can create their own goods and make money from them.

If the game designer isn’t ready to handle the demands of emergent communities, it’s easy to head off. Single-player game designers don’t have to worry about this so much. You can also take away persistence (which is returning to a game and finding that all of the things you’ve collected are still there).

Kabam, which runs strategy games like The Hobbit: Kingdoms of Middle-earth, eventually bought Realm of the Mad God creator Wild Shadow Studios and still runs it today. Given the huge load that came from fan emergence, that was a natural outcome, as the indie developers could no longer keep up with the fans.

“These kinds of games are insanely scary, with high variability from what you originally designed,” Cook said. “If you want to create this, you’ll need an agile development team to keep up with it.”