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) in "Angry Birds Rio" and the introduction of the orange bird that first appeared in "Angry Birds Seasons". The update was later released for Android and Microsoft Windows. The eighth update was released initially to iOS on March 20, 2012 in a lead-up to the release of "Angry Birds Space". The new update included an animated tutorial, enhanced gameplay, all new UI graphics, and the first 15 levels of "Surf and Turf," the "Angry Birds Facebook"-exclusive episode (see below), another 15 levels were added later, with the iOS version receiving the power-ups first seen in the Facebook version. On October