Rovio the creator of the hit mobile game "Angry Birds," reportedly turned down a $2.25 billion acquisition offer earlier this year from Zynga, the San Francisco-based social gaming developer.

The claim is unconfirmed by Rovio, and Zynga cannot comment since the company is in its pre-IPO period. Sources said that Rovio walked away from discussions of a deal that would've given the start-up about $2.25 billion in cash and stock.

Zynga had reportedly tried to acquire another games company in July, but failed to do so. PopCap Games, the makers of Bejeweled and Plants vs. Zombies, turned down an acquisition offer worth $950 million.

Rovio’s CMO Peter Vesterbacka recently announced that Angry Birds has become the most downloaded game of all-time and fastest-growing game in history, scoring 500 million downloads in less than two years since its December 2009 release.

"This is a fantastic landmark achievement for us, and we're extremely delighted to see such an incredible amount of people enjoying our games," said Rovio CEO Mikael Hed. "We remain committed to creating more fun experiences and bringing exceptional quality to 'Angry Birds' fans everywhere."

The Finland-based company also said that Angry Birds is now the No. 1 game in 79 countries. For those who have never played Angry Birds, the game is simple: players use a slingshot to launch multi-colored birds at structures populated by evil green pigs. Players must eliminate all of the pigs from each level before moving on. There are currently three different iterations of the game, including the original 'Angry Birds,' the holiday-themed 'Angry Birds Seasons,' and 'Angry Birds Rio,' which was released as a promotional tie-in with the 20th Century Fox animated film "Rio."

But even with three games and countless levels, people still want more Angry Birds. The company has been growing in size to accommodate the high demand, developing a long line of Angry Birds-themed toys, apparel, accessories, board games and a cookbook. Recently Rovio opened up its first Angry Birds store in Helsinki, Capital of Finland. The Company also plans to open up shops in China, where the brand is huge - it's Rovio's second-largest and fastest-growing market.

"We're insanely profitable," Vesterbacka said. "We are very, very profitable. We're not a publicly traded company yet but we can fund our own growth."

Vesterbacka believes Rovio is "not ready to file for an IPO tomorrow," but sees his company going public in "maybe a year from now."

Despite reports company employees are dissatisfied with Zynga, the company still hopes to go public by the end of the year. The company aims to raise $1 billion to achieve a valuation between $10 billion and $20 billion.

Zynga has 60 million daily active users who daily play its various games, including titles like FarmVille, CityVille and Words with Friends. The company also boasts more than 269 million monthly active users on Facebook, the platform which gave Zynga immense popularity.