Angry Birds Opera

Angry Birds Opera was a version of Angry Birds available for PCs using the Opera web browser, the game was released on the version 12 alpha of Opera Next on October 13, 2011, and closed it's servers one day later on October 14, 2011, as a result, the domain was also closed for a while until it finally expired sometime in the late 2010s, the game was located on opera.angrybirds.com.

The game was announced by The Register on October 11, 2011, and was meant to be available two days later on October 13, 2011, it released and was able to be playable for one day until October 14, 2011, when Rovio closed the game's servers without telling anyone

Episodes
Poached Eggs (the first episode of Angry Birds and has appeared in a lot of webgames)

Trivia

 * The game was released for a day on October 13, 2011, apparently and closed it's servers one day later on October 14, 2011
 * The game wasn't finalized probably due to there being a lot of games to work on for Rovio and was the first Angry Birds webgame to use HTML5 before Angry Birds Chrome switched to it in 2012 onwards
 * The domain opera.angrybirds.com seems to be co-owned by Rovio and Opera seeing that this game was meant to be played in Opera browsers only

Angry Birds Opera