They grow up so fast, don't they? Angry Birds - the physics-puzzler from Rovio that truly needs no introduction - turns two years old today.

What was once a humble game about "reclaiming eggs from some pesky thieving pigs" is now a worldwide sensation. The game features 740 stages, the series has been downloaded half a billion times, and there's more merchandise than you can count.

To celebrate the meteoric rise of this uber-popular phenomenon, we're counting down the ten milestones from the past two years - from releasing on the App Store to its 500 millionth download - that made Angry Birds what it is today.

December 10th, 2009 - Angry Birds launches on iPhone and iPad


In December 2009, a 59p physics-puzzler called Angry Birds landed on the iPhone and iPod touch.

Developer Rovio and then-publisher Chillingo gave the game the sort of inauspicious launch that you'd see for any old 59p app, and not the ceremonious birth of a global phenomenon that would go on to sell half a billion copies.

The first App Store description for the game described it like this: "the survival of the Angry Birds is at stake. Dish out revenge on the green pigs who stole the Birds’ eggs. Use the unique destructive powers of the Angry Birds to lay waste to the pigs’ fortified castles."

It only had 63 levels (now the same game has 258 stages to play) and a few basic birds, but it set the foundations for what was soon to be a towering franchise of mind-boggling proportions.

February 11th, 2010 - Angry Birds gets its first update


By February, nimble-fingered bird fans had already blitzed through the 63 levels on offer - and they wanted more. Rovio responded in kind, doling out a free update with the Mighty Hoax episode and 42 new levels to go with it.

The update also provided leaderboards and achievements through Crystal (Angry Birds would later go on to accommodate Apple's own Game Center), and "New block shapes, including triangles". Ah, times were so much simpler back then.

The vanilla Angry Birds has continued to be updated until this day, with 21 app updates, a further five episodes, an extra 153 levels, the golden eggs, new birds, and the Mighty Eagle in-app purchase. Phew!

March 8th, 2010 - Angry Birds starts to gather momentum


Angry Birds had a quiet launch, but it quickly grabbed people's attention and soon spread like a infectious disease amongst iOS gamers. By March, just three months after the game hit the App Store, Rovio was celebrating half a million sales.

"Chillingo is really the App Store kingmaker," Mikael Hed, CEO of Rovio, said in a press release at the time. "No other company has managed to repeatedly raise previously unknown titles to the top of the App Store charts, making them into leading game brands as they have done with Angry Birds."

Little did Hed know, but by the end of the year Rovio would be leaving its "kingmaker" publisher behind. "We will not use Chillingo again," company chief Peter Vesterbacka told TechCrunch in October 2010. "You don’t need publishers," he said. Rovio now handles its own games.

October 20th, 2010 - Angry Birds Seasons launches


Angry Birds got its first proper sequel close to the franchise's first birthday. Seasons - then called Angry Birds Halloween - was a holiday special, dressed up in ghouls and pumpkins, that Rovio was asking another 59p for.

Much like the first game, this seasonal spin-off has seen its fair share of updates. The app soon turned into Seasons, as Rovio dropped 25 Christmas-themed levels for the winter season. It was subsequently updated with every holiday occasion under the sun during the following year.

We celebrated Valentine's Day with "Hogs and Kisses", St Patrick's Day with "Go Green, Get Lucky", Easter with "Easter Eggs", the balmy middle months with "Summer Pignic" and the Chinese mid-autumn celebrations with "Moon Festival".

And now the title has come full circle, with new Halloween and Christmas level packs for the new year.

January 3rd, 2011 - Angry Birds flies the mobile coop


Angry Birds was born on iPhone, and throughout 2010 the series flocked to various other mobile devices. Nokia's Ovi got a version as did Palm's webOS operating system and any phone running Symbian 3. iPad got a supersized HD edition, and Android got an ad-supported free version in October.

But as soon as the bells rang for 2011, Rovio's ambitions grew. In January, the original Angry Birds game (with its original 63 stages) was released as a PlayStation mini. This let smartphone-challenged gamers sample its addictive taste on PSP and PlayStation 3.

Other versions are reportedly in the works. An Xbox 360, Wii, Nintendo DS, and extra-dimensional 3DS version have all been promised, hinted at, or rumoured to be in development.

March 21st, 2011 - Angry Birds teams up with Fox for Rio


Is Angry Birds an advertising platform? "Absolutely, absolutely, absolutely, absolutely, absolutely," Rovio CEO Peter Vesterbacka told Business Insider. And Rio, the game's third iOS app, certainly proved as much.

The game was released in March as a marketing tie-in with the 20th Century Fox film Rio, featuring characters and locations from the kids' flick.

It was even seen at the Super Bowl. During the famously expensive ad breaks, a Rio commercial sent players to a special level in Angry Birds to unlock a golden football.

This wasn't the last time that the birds were trotted out to sell something. Those pesky avian assassins have been used to flog Nokia phones, Samsung tablets, Google's Chrome browser, Microsoft's Bing search engine, and even Wonderful Pistachios.

November 2nd, 2011 - Angry Birds hits half a billion downloads


Half a billion people have played Angry Birds. That's half the population of India, and eight times the number of people in the United Kingdom right now. 1/14th of the globe's population has played Angry Birds. That's a lot of people.

Along with that eye-popping stat, we found out that gamers around the world have played a total of 200,000 years of Angry Birds, and Homo sapiens - in total - spend 300 million minutes a day launching birds at smug pigs.

More than 266 billion levels of Angry Birds have been played, and 400 billion birds have been launched into rickety wooden shacks. Over 44 billion Stars have been collected in the process.

November 11th, 2011 - The official Angry Birds shop opens


You thought the M&Ms World shop in Piccadilly Circus was bonkers? In Helsinki, Finland, an entire store has been opened up to sell Angry Birds merchandise. That includes the likes of - deep breath, everybody:

Angry Birds plush toys, keychains, beanie hats, pillows, Christmas stockings, iPhone cases, backpacks, lunch boxes, drawstring bags, shoulder bags, fridge magnets, flip flops, socks, ties, Halloween costumes, cookbooks, baby clothes, boardgames, T-shirts, hoodies, badges, money banks, alarm clocks, and a hell of a lot more.

November 25th, 2011 - Angry Birds goes retail


Angry Birds has always been digital. Whether it's as a smartphone app, a browser-based game, or a PSP download, Angry Birds has always shipped on 0s and 1s. But, in November, the game went physical.

You can now buy Angry Birds on a CD and in a box from a shop, for those that really want to play Angry Birds but don't have an internet connection. You'll have to pay £6.99 for the privilege.

December 11th, 2011 - Angry Birds celebrates its second birthday


500 million downloads, three games, endless different versions, eight birds, 740 levels, and who-knows how many man-hours wasted, and the Angry Birds franchise is celebrating its second birthday on the App Store.

There's an update for the original game - offering 15 new levels with special achievements, plus all the episodes have been unlocked - as well as promotions in Barnes & Noble; Toys R Us; the Apple store in Ginza, Japan; and Forbidden Planet in London.

So, what does the future have in store for Angry Birds? 2012 will see as many as four new games featuring the birds, and we might get closer to seeing that movie adaption of this now global phenomenon.

Want more? Check out our 18 other Angry Birds features!