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 Go! the gameplay and was not overly bothered by the in-app purchases. "Tech2" did not like the energy system, which only allows you to play five races with a bird, after which they are locked unless you wait or unlock with crystals (which are slowly earned in-game or with an in-app purchase) and did not like the vehicle upgrade process using in-game currency that is slowly earned by racing or with an in-app purchase for coins. Angry Birds Go! Angry Birds Go! is a kart racing game and the eighth game in the "Angry Birds" video game series. The game was