The gameplay in the Facebook version hasn't changed much, but there are new social elements, brand new power-ups, and Facebook-exclusive levels.
Leaderboards will be automatically generated based on your friends on Facebook, and you'll be able to share your best scores to your Wall. You can also share power-ups via "mystery gifts" with your friends.
Power-ups are crucial to monetizing Angry Birds on Facebook. While you can get some power-ups for free, you will need to purchase new ones once your supply is depleted. Besides, don't you want an edge over your friends as you vie for first place?
"This launch is just the beginning for Angry Birds on Facebook," Rovio's Petri Järvilehto said in a press release. "We have great new features and gameplay lined up for the fans in the upcoming weeks."
You can play Angry Birds on Facebook here. If you play between now and February 16th, you'll get 14 free power-ups.