Decrem heard the news while travelling on business in South Korea on his way to China--coincidentally, the country where the 25 billionth download was recorded. While in China, Decrem visited Apple's flagship retail store in Beijing, where store employees were giving demos of Where's My Water? on the iPhone.

"It was a big thrill," Decrem said.

It was also a gratifying moment for Disney Mobile. Where's My Water? marks the first game developed by the entertainment giant to star an original character created specifically for the mobile market. Previous Disney Mobile efforts involved either movie tie-ins or games developed by other companies that Disney had purchased. (The popular Tap Tap Revenge games, for example, are now part of Disney's portfolio after the . Decrem, in fact, joined Disney as part of that acquisition.)

The key to developing a hit iOS game, Decrem says, is to avoid being derivative--not an insignificant point in an App Store that often feels clogged with Angry Birds knock-offs. Instead, the development team behind Where's My Water? focused on the gameplay. Half-a-dozen people spent time playing with the core mechanics behind the game--for instance, digging with your finger to move water through soil. From there, Disney Mobile was able to build out the story, characters, and world that Where's My Water? inhabits.

"The App Store rewards awesome experiences," Decrem said. "We told the team to build just the best experience you can."