It's four years since a struggling eight-man team in Espoo, Finland, released a $1.99 iPhone game on the budget label of a little-known UK publisher-aggregator.

One price cut and a couple of months later, Angry Birds had sold its first million. The franchise has since gone on to do two billion downloads, generating over $500 million in gross revenue, while Rovio in 2013 is a 800-strong company with offices all over the world and an animated movie due in 2016.

Such is the world of mobile gaming.

In that context, the first simultaneous game launch for iOS, Android, Windows Phone, BlackBerry 10 and Amazon Android might not compare.

But thrown in the detail that Angry Birds Go - developed by UK studio Exient - is the company's first from-the-ground-up free-to-play game, not to mention its first 3D game, and the first Angry Birds game in a new genre, then its significance starts to grow.

Something new

Jami Laes, Rovio's EVP of games, is happy to point out that following seven 'classic' Angry Birds releases, the company is now actively looking to take the iconic characters into new experiences.

"We wanted to make a game in a different genre," he reveals.

Of course, any new Angry Birds games have to fit within the existing Angry Birds' universe.

"Never say never, but I think it would be hard to make an Angry Birds first-person shooter," he says.

So, in this context, Angry Birds Go, while being a downhill kart racer, is firmly influenced by what has gone before.

"It's not a kart racer with laps where you try to reduce your [lap] time," he says, when asked how Mario Kart influenced the game's evolution.

"We thought that would be too hardcore. While we think Angry Birds Go will initially appeal to a more core audience, just as Angry Birds was played by everyone, we've designed Go to be accessible to people who haven't played kart games before."

The game also meshes with longstanding franchise themes in terms of how it uses Angry Birds' characters and their power ups in gameplay, something combined with plenty of bird versus pig humour.

Welcome to the new world

Perhaps the biggest innovation for Angry Birds Go, however, is its business model.

While Rovio has released plenty of games with in-app purchases, this is the first high profile release of a true free-to-play Angry Birds game.

As you'd expect from Rovio, the in-game economy is clean and clear.

There's a hard currency - gems - which is used to buy some exclusive karts, refill a character's energy bar, and for items. It can also be converted into the soft currency - gold - which is used to upgrade the components of your kart, and buy new ones. Store purchases range from $2.99 to $99.99.

"When it comes to in-app purchases, we want to take it easy, and make sure we're responsible. We are a 'mum approved' brand," Laes explains.

"But, we're not reinventing how IAP work. We're following what other developers do. I think that [reinventing] would be confusing."

One nice touch, though, is that the energy mechanic is centered on playable characters, which you unlock as you beat them as in-game bosses.

Each character has five energy slots, providing a tactical element in terms of how you use them and their power ups. And, with multiple characters to unlock, the further you progress, the longer you can play before having to wait for each character's energy to refill or spend some hard currency.

"In other F2P games, you effectively end up with less energy the more you play," Laes says.

"With Angry Birds Go, we give you more energy as you play, because you can unlock up to 10 different playable characters. So there our approach is the reverse of the industry norm."

Beam me in

Another area in which Rovio has demonstrated its power is the way Angry Birds Go integrates the company's extensive merchandising operations.

Following Angry Birds: Star Wars IIdebut, Go uses the telepod system, which enables branded toy karts (distributed by Hasbro) to unlock their digital versions within the game using a QR code and the device's camera.

Building on the success of other physical-to-digital products such as Activision's Skylanders, Disney's Infinity and Angry Birds: Star Wars II (which has sold one million telepod units), Laes says it provides an additional option for parents who don't want to enable IAP in their children's games to control the unlocking of new content.

Of course, it's an additional revenue stream for Rovio, which as well as toy karts is selling complete race tracks and a physical Jenga pig pirate ship, which can also be unlocked in-game.

More can be more

Yet, perhaps the most important meaning that can be taken from Angry Birds Go is that after four years, Rovio is now serious about extending its game portfolio.

Same characters, same universe for sure, but while Laes won't go into details for obvious reasons, 2014 will see new games and new genres.

"We want to take the Angry Birds and Bad Piggies brands in new directions, as well as come up with new games and new characters outside of the Angry Birds brand," Laes says.

In a similar context, he says that the Rovio Stars publishing initiative will continue.

"We've released three games in six months. I don't think we want to accelerate this. We're very selective," he ends.

"We're happy with the results, and the developers are happy too."