Angry Birds (video game) crates and rocks are incorporated into the structures, and power-ups may be used to enhance the birds to attack hard-to-reach pigs. Also in the levels, players can unlock bonus levels by collecting golden eggs. There are several different types of birds used in the game, distinguished by their color and shape. In the earliest levels only the basic red bird is available. As the player advances through the game additional types of birds become available. Some birds are effective against particular materials, and some have special abilities that may be activated by the player while the bird is airborne. For
Angry Birds (video game) birds higher and faster. Power-ups can be purchased in-game or given by friends who also play the game. "Surf and Turf" would later be included in the original mobile versions of the game, starting with iOS. The Facebook version features weekly tournaments among your friends, with the top 3 winners earning free in-game "Bird Coins" which can be used to purchase power-ups. There was a unique Green Day themed chapter, however it was removed in December 2012. At the 2012 Electronic Entertainment Expo in Los Angeles, California, Rovio and distribution partner Activision announced plans to bring "Angry Birds" and two