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) the top 10 for paid iPhone/iPod apps, while its iPad-exclusive "Angry Birds HD" versions were the top-selling and top-downloaded iPad apps for the year. Mattel also made a few board games based on the app. These were called "Angry Birds: Knock on Wood, Angry Birds: On Thin Ice" and "Angry Birds: Mega Smash". In February 2010, "Angry Birds" was a nominee for the "Best Casual Game" award at the 6th annual International Mobile Gaming Awards in Barcelona, Spain. In September 2010, IGN named "Angry Birds" as the fourth best iPhone game of all time. In April 2011, "Angry Birds" won