Google's Chrome version contains an exclusive level today, which connects to a secret microsite where users can then play a different version of the Angry Birds Season game - on top of the 25 advent-style levels.
This is the first time Rovio has designed a bespoke game, and one that allows the top 50 scoring players to win a Samsung Galaxy Note with Angry Birds merchandise.
The fifth level is bejewelled game, where the prizes for the top scores are a 5.3-inch screen based Galaxy Note, with a selection of 10 of the games' toys; a second prize is a Galaxy Note and 5 of the merchandise items; the third prize is a Note and any one of the Angry Birds toys and fourth to tenth winners get three of the toys for each.
Player of the game are also able to send personalised Angry Birds themed Christmas cards, along with a seasonal video.
Head to http://note.angrybirds.com/ to play the game now.