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 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