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) was developing new ports of the game, this time for devices outside of the mobile phone market. In January 2011, three of those ports launched. First, Sony announced the release of "Angry Birds" for its PlayStation Portable handheld system in the form of a PlayStation mini game that includes nearly 200 levels from the original game; the version is also playable on the PlayStation 3. Next, Rovio announced the release of a Windows version of the game on January 4, 2011, available for sale exclusively from the Intel AppUp center, which included 195 levels at launch and plans for exclusive