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) were released, Angry Birds became "Free App of the Week" on the Apple App Store until March 14, 2013, and became an instant hit on the Top Free App charts on the App Store until March 18, 2013, when the app returned to the normal price of $0.99. On June 17, 2013, Rovio teased on its Facebook page that Red, the main protagonist of the game, would receive an ability in a new episode. On June 26, 2013, Rovio released a YouTube video, uncovering three new facts: the episode would be called Red's Mighty Feathers, the update would come in