“The whole project was an experiment,” Crossy Road co-creator Andrew Sum tells me. “We had no idea how the game would perform.”

By most measures, the experiment was a remarkable success.

Sum and his fellow Hipster Whale co-founders Ben Weatherall and Matt Hall launched Crossy Road into the Apple App Store in late November; 20 days later, the free-to-play “endless Frogger” had been downloaded over a million times and grossed over a million dollars from in-game video ads, provided via Unity Ads.

"We far exceeded any financial goals we had," says Sum. "We were aiming to make enough money to fund development of future titles," and now the team -- formed just months before launching the game -- is well-equipped to do so.

What's particularly interesting about their success from a developer's perspective is that the video ads which have been so profitable for Crossy Road are designed to be as inobtrusive as possible -- players can choose to watch one in return for a small payout of in-game currency, or skip them entirely.

That currency (which can also be earned by playing the game, waiting a few hours, or paying real money) can then be spent on "pulls" of a machine that awards the player a random new character, some of which cause cosmetic changes in the game.

“Matt and I aren’t fans of consumables, so we wanted to be transparent with our in-app purchases,” says Sum. The pair wanted a monetization system that was accommodating for players who wanted to spend a dollar, and only a dollar -- they didn’t want to risk turning off people by sticking to (proven) F2P models like forced advertising or energy systems that can be circumvented with IAP.

“We aimed to design something that would be appealing to everyone, rather than a system that only a small percentage would contribute to,” says Sum. “Matt had seen video ads in other games,” particularly Disco Zoo from Milkbag Games and NimbleBit, “so we brainstormed for a while about how they could work in our game.”

What Crossy Road learned from Dota 2

Hipster Whale also looked to other successful free-to-play game developers for ideas on how to smartly monetize Crossy Road, especially Valve. 

"We were also inspired by games like Dota 2, where any real money you invest into the game has no impact on the gameplay," says Sum. Hipster Whale wanted their debut game to be played by as many people as possible, and Sum says all of their design decisions revolved around that desire.

The creators of Crossy Road have been upfront about taking design cues from Skylanders, Temple Run and other successful titles, but Sum says "we were mostly inspired by Flappy Bird and the 'one more go' feeling it invoked."

The team "took away anything that got in the way of that core loop" in an effort to ensure the game hooked as many people as possible, and it seems to have paid off.

"We didn't think we would make a lot of money," says Sum. "But it turns out that players are happy to support the game, so it turns out the experiment turned out to be a success."

In the wake of that success, Sum advises his fellow game developers to keep their players in mind when figuring out how to monetize their work.

"Treat your players with respect," says Sum. "Make a game that people will want to share, and encourage them to come back tomorrow."