The original Angry Birds game was released in 2009. Rovio Entertainment first launched it for mobile devices, with the international iOS release arriving on December 11, 2009, after an earlier soft launch in Finland.
The game was created during a difficult period for Rovio, which had already developed dozens of games and was struggling financially. Designer Jaakko Iisalo proposed a sketch of wingless, angry-looking birds, and the team built a physics-based puzzle game around those characters. Players used a slingshot to launch birds at structures sheltering green pigs.
Angry Birds initially appeared to be a modest mobile title, but it became a major success after being featured on the UK App Store in 2010. Its popularity led to sequels, spin-offs, animated series, merchandise, films, and a much larger media franchise. The 2010 release of Angry Birds Seasons is sometimes mistaken for the original game, but it was the second major title in the series.