[Two-man indie Nimblebit explains to our own Simon Parkin its move to a free-to-play model, detailing how that decision has led to the team's latest iPad game, Pocket Frogs, securing 1.25 million downloads in just 14 days.]

The invasion of free-to-play Facebook games such as FarmVille and Mafia Wars onto the App Store has come as no great surprise. With player bases that dwarf that of most console games, the idea that players would want to take these social games mobile -- and that their creators would want to provide a new gateway from which to profit from them -- is natural.

As a result, these games dominate the top grossing iPad game chart, propelled there by the endless micro-transactions their players make in an effort to get ahead of their friends.

Nimblebit’s Pocket Frogs is a game that, like Zynga’s catalog, is free-to-play, generating revenue from players’ in-game purchases.

Despite being an App Store original, with no established social network audience to drive downloads, Pocket Frogs was downloaded 1.25 million time in the two weeks following its release, and now sits firmly in the Top 40 top-grossing titles on the platform.

At a time when indie developers still seem suspicious of free-to-play games, Nimblebit, a studio run out of a one-room office in San Diego by twin brothers, David and Ian Marsh, has embraced the approach. “We have experimented with the free model in limited amounts in the past,” explains David.

“We converted one of our most popular games, Scoops, into a free-to-play game, and from those results were confident that the model could work just as well as a traditional paid game," he adds.

“After seeing the results of all our past experiments with free apps,” he continues, “we were extremely excited about the exposure that free apps could generate. Pocket Frogs was our first opportunity to release a game that is free-to-play from the start."

"We generate revenue though selling in-game items through in-app purchases, as well as a limited amount of advertising in some of the game sub-menus,” he continues . “The in-game items we sell are targeted towards ‘power users’ who are willing to pay to progress through the game quicker.”

It’s this particular aspect of the free-to-play model that, arguably, deters indie developers, many of whom have ethical concerns over the idea of drawing a player in to a game -- and then withholding content in order to make money. “We were very careful to make sure that these purchases were only a bonus, and not simply a paid way to access a crippled game,” counters Marsh.

How It Works

“Free players can earn the same items through normal play, and from day one until the end of our testing we were tuning the game from the perspective of free players," he explains. "We want everyone to get maximum enjoyment out of Pocket Frogs, whether they choose to spend any money or not.”

The approach is certainly working. “Pocket Frogs is on pace to be our fastest growing and most profitable game to date,” he explains. “Our daily active users count is growing, and this weekend peaked at 350,000. We don't have all the figures to calculate exactly how many users are choosing to purchase in-game items, but we estimate it is somewhere in the ballpark of 2 percent, which is pretty standard for free-to-play games.”

For the Marsh twins, it’s not all about making a profit. Both men previously worked in larger studios, David as a level designer at Troika Games on Vampire: Bloodlines, and at Midway San Diego while Ian worked at Chumby as a flash developer. “We were inspired to strike out on our own after a long string of successive layoffs and company failings that left us very frustrated,” says David.

“We figured that since there didn't feel like there was very much security in working as an employee in the industry that we would try to do it on our own. Just the two of us work here. We don't have any employees, and we don't really aspire to have any in the future. Our goal is not to grow the size of the business, but to sustain our ability to work on our own games for as long as possible.”

The small studio set-up allows the pair to rapidly develop and iterate games. “I usually mock up the games as we are doing our initial design brainstorming and then start feeding art assets to Ian, who starts arranging them into functional pieces using cocos 2d, an Open GL iOS graphics framework."

"One of our favorite things about working together is that we can put games together extremely rapidly," he adds. "Some of our games, like Dizzypad, took just 2 weeks to put together, while more complex titles like Pocket Frogs still take us only 2 months. This allows us to pretty much follow our curiosity as developers, and just start working on whatever strikes us as interesting at the moment without much risk.”

An Easy Decision

The decision to move to a free-to-play model has influenced the way that the team goes about designing games. “It takes some special care to design a free-to-play game in such a way that it does not feel hobbled,” says David, “and that the motivation to pay for the game is to fix it. It is very easy to put roadblocks and tollbooths in a game, but I don't think that it is necessary. I honestly don't think that there is a need to funnel people towards paying for the game. If the game is enjoyable, there will be enough people that will enjoy paying for it of their own volition to make up the difference.”

“Going free-to-play didn't really seem like a gamble at all,” he explains. “It took about 2 months for us to make Pocket Frogs, and for us the worse case scenario would be that lots of people would get to play it for free. That is the main reason we make our games, we want people to play them. So there really didn't seem like a lot of risk there.”

For the twins, the free-to-play model has come to seem like the lower risk option when it comes to development for Apple’s systems. “Many people have always been playing games for free, so much so that paying upfront for access to a game seems backwards to them,” says David. “This is increasingly becoming the way that a large segment of people prefer to play games."

"They want to discover, download and play something in a matter of seconds," he adds. "They don't want to research a game, or try to guess whether it is worth 99 cents or 2 dollars or 5 dollars to them. Many people will simply stick to free games in order to avoid that. There is certainly no scarcity of free games and entertainment.”

Following the gigantic success of Pocket Frogs, Nimblebit is happy to move their operations wholesale to a free-to play model. “I think the majority of our games will be variations on the free-to-play model,” says Marsh.

“All indications from our past experience would seem to indicate that if we had launched Pocket Frogs as a paid game, it would only have been experienced by a fraction of the amount of players that are experiencing it now. If we can give many more people access to our games while still making revenue then there are really no regrets for us to have.”