As a celebration of the second “birthday” of Angry Birds – the ultra-popular and wildly successful game that so many people know and love, Rovio has released Angry Birds version 2.0. While the update is mainly evolutionary, rather than a full-fledged “Angry Birds 2″, it continues Rovio’s commitment to delivering new content to players.

Angry Birds 2.0 brings 15 new levels to the game, along with modifying how the player progresses through the game. Now, all the “episodes” (sets of levels) are unlocked from the start, allowing new players to jump right into any of set of levels rather than playing them in strictly sequential order.

Angry Birds is available on a multitude of platforms, including all iOS devices (with an appropriately-scaled “HD” version for the iPad), along with Android devices and even a web app available for the Chrome web browser. Angry Birds for iPhone and iPod touch is available for $0.99, and Angry Birds HD is $4.99.