Angry Birds (video game) was being played, the staff liked the characters, and the team elected to design a game around them. In early 2009, physics games, such as "Crush the Castle", were popular flash-based web games, so the Rovio team was inspired by these games. During the development of "Angry Birds", the staff realized the birds needed an enemy. At the time, the "swine flu" epidemic was in the news, so the staff made the birds' enemies pigs. Angry Birds was the studio's 52nd produced game and on its initial release, the game did not sell many copies. After Angry Birds was a
Angry Birds (video game) in revenue from the advertising that appears in the free Android version. According to Rovio, players logged more than 5 million hours of game time each day across all platforms, with the series having 200 million monthly active users, as of May 2012. In November 2010, Digital Trends stated that "with 36 million downloads, "Angry Birds" is one of the most mainstream games out right now". MSNBC's video game news blog has written that "[n]o other game app comes close" to having such a following. "The Christian Science Monitor" has remarked, ""Angry Birds" has been one of the great runaway