I'll cut straight to the chase: Angry Birds on Facebook is basically a huge slice of Angry Birds with a competitive leaderboard and purchasable content dabbed on top.

On paper, that doesn't sound like enough to get fans of Rovio's immensely successful series excited, but this simple re-focusing away from grabbing stars and towards chasing high scores turns the physics-puzzler into a far more vicious game than the one you'll be used to.

Sparrowhawk

Angry Birds on Facebook - which took flight earlier today - comes with three sets of levels: two from the first game (Poached Eggs and Mighty Hoax), and one exclusive bunch for Facebook called Surf and Turf.

All have the first level unlocked from the start, so there's no need to slog your way through the familar green fields of Poached Eggs before you reach the new batch.

As with the original iPhone game, Angry Birds on Facebook operates a 3-star scoring system based on how much damage you manage to inflict on the pigs' structures and the number of swine you kill. Bonus points are handed out for any unused birds standing behind the slingshot.

There's also a separate scoring system reserved for the Mighty Eagle. Should you use this level-beating power-up (you get a few tries for free when you start the game), then the amount of destruction is measured in feathers instead.

Leaving the nest

So far, so Angry Birds on your smartphone. It's at this point, however, where the Facebook version starts to go down its own path: one that will likely act both as an incentive to play and as a deterrent for purists.

When you launch the game for the very first time (and on every consecutive day you log in), you're given a bunch of power-ups to use during the level. These aren't as powerful as the Mighty Eagle, thankfully, but on the flip side, they will help boost your score in some way or another.

The most obvious ones are the Super Seeds, which make your birds bigger and stronger than normal; and the King Sling, a powerful slingshot that sends your feathered friends farther and straighter than the usual sling.

Birdquake, on the other hand, is fairly useless, but it does apply a nice blurring effect to the screen when you use it.

I am the winger

Importantly, the emphasis of Angry Birds on Facebook is firmly on beating your friends' scores. To keep track of the competition, a leaderboard is displayed down the side of the screen, which updates in real time and shows you just how much you need to get in order to the claim the prized crown for that particular level.

Should you move past an opponent (either through pure skill or by using a naughty power-up), you can instantly send a "brag" to them by hitting a button by their name. If you're not quite as mean as that (you will be after a few levels, trust me), there's also the option of sending a free gift across to help them improve their score.

One thing that is interesting about the game is how real-world money is implemented into the experience - rather than advertise the price of an item in Facebook Credits, Angry Birds charges in dollar denominations.

Also of note is the relatively cheap pricing of the items compared to other Facebook games: 20 uses of a single power-up will cost you a reasonable $1, for example, while 15 uses of every power-up available will set you back $3 (bought in a bundle).

Have I felt compelled to pay? Not really, but given time (and more competition), I can see quite a number of people paying a few coins to one-up their mates.

With avatars promised for the future alongside the almost-inevitable content updates (read: further levels from the smartphone series), Angry Birds on Facebook appears to be another shrewd expansion of Rovio's gaming behemoth.

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