In the extras menu there are 2 menus:

-Soundtrack

-Cutscenes

The Soundtrack menu has the soundtrack from Angry Birds, Angry Birds Seasons, Angry Birds Rio and Angry Birds Space. There is a separate page for ambience. You can mark your favourite tracks and only play those. You can also play through all the tracks and speed them up to 2.0 speed.

In the Cutscenes menu you can watch the cutscenes from this game.

Both the tracks and the cutscenes you have to buy with Bird Coins. One track or one cutscene cost 10 Bird Coins.