Originally released for the first time on iOS in December 2009, Angry Birds was the platform's first major gaming hit. Six versions of physics puzzler later and we've arrived at a cross-roads with the new free-to-play racing game, Angry Birds Go!.

Not only does the new Angry Birds racer forego the $0.99 price tag, it's a different genre of game entirely. Rovio's shaking of the nest is undoubtedly a bold move – but does it work? Read on...

The Same, But Different

Believe me when I say Rovio are still in the business of creating physics games. In fact, a racing game was probably the most logical choice for a development studio that built its name on physics puzzlers. Every racing game needs a physics engine, and this one is no different.

The game takes the level-based gameplay model of Angry Birds and the comic vehicular stylings of Bad Piggies, delivering a fully-3D racing game controlled from a third-person perspective. Each "race" is a level, and you'll need to beat other racers, complete challenges and eventually beat a boss-type character in order to unlock tracks, birds and further your racing career.

Despite being a racer, the game still manages to pack-in a few classic Angry Birds references. Each race is started using the iconic slingshot, for example – requiring you pull back, wait for the timer to reach "Go!" then release to start the race. From there on out, all you'll need to do is steer your kart around the track, avoiding obstacles and other racers. Your kart has no ability to manipulate its position in the air, so much of the puzzle aspect involves taking skillful approaches to bumps in the road.

Each character gets a special power-up, of which the first use is always free. These range from speed boosts to bombs, but if you're expecting a Mario Kart-style red shells and bullets then you're going to be disappointed. The only pickups on the race track are gold coins and gems (the two in-app currencies) as well as challenge objects. There's no accelerator, no brake pedal but the directional controls feel very responsive.

And that's exactly what I mean when I say Rovio are still making physics games. The fact that you're only able to steer left and right reduces driving to its simplest form – much of the time a tumble down a hill making slight corrections. It's still a physics game, and it's actually quite fun.

Each track offers five events – a race, against other competitors; a time attack mode; a "fruit splat" mode, where you must hit a minimum amount of fruit; versus mode, which pits you against a racer of varying skill and the "boss" battle that requires you beat a certain character three times. Once you've beaten this character, they join your "tree" and you can then race with them. Of course, there's a bit more to it than that.

Because of how much you end up racing on one track before progressing to the next, the circuits can get pretty boring pretty quickly. Minor differences in race mode, obstacles and rivals keep it interesting, and thankfully there are a few routes to take on each track, but clearing a track ends up being quite a repetitive process.

Free-to-Play Madness

To answer a question that many people will be wondering: is the free-to-play aspect instrusive? Yes, absolutely. When is it not?

Angry Birds Go! uses a system of "energy" in order to restrict how much you can play the game. Each character – each bird, that is – has a maximum of five points of energy. Start a race, and you'll use one up. Screw up half-way through the race and decide to restart, and you'll use another. Once one bird runs out of energy, you'll need to rest him by waiting a pre-determined amount of time, pay for a recharge using the premium in-app currency (gems) or choose a different bird to carry on with.

After a good few hours of playing, I'm still only waiting about 20 minutes for each bird to recharge and I've yet to use any gems. The game does supply you with gems, but I'm the sort of person who would rather wait the five minutes for something to recharge than use-up some virtual currency I got for free (I know). Unfortunately, this has the effect of making playtime seem finite each time you sit down to play. I'd rather pay for the game outright and not have to worry about janitoring gems or energy levels.

And then there's the overall feel of the game being a bit of a cash grab, like charging $7 for a coin doubler. Coins are used to upgrade your kart and for little else, and many developers provide doublers for far less than $7 – some even award this to users who follow them on Twitter or Facebook for free. Then again it looks cheap compared to the $50 in-app purchase for a kart.

Fifty dollars for an in-game vehicle. You could buy many of the games on our Best iPhone Games page for that sort of money. There are cheaper vehicles available to those who don't want to pay ludicrous sums of money, but you'll be using a lot more energy in a kart with terrible specifications by taking that route (and thus have to switch, rest or recharge all of the time).

Fun But Frustrating

The game portion of Rovio's latest release is good, but the free-to-play model is not. Graphically, Angry Birds Go! looks like a polished console racer, with a delightful colour palette and silky smooth framerate (on an iPad Air). The racing action itself is responsive and at times even satisfying, which is what makes the free-to-play model so frustrating.

The whole time I played I couldn't help but feel that I'd rather pay a few dollars and enjoy the game, rather than worrying about when my borrowed time is going to run out.

Rovio have built a solid yet simple racing experience that's probably going to resonate very well with existing fans of the series. Unfortunately for Rovio, this audience is used to paying their dollar and playing to their heart's content and many will find that the freemium model gets in the way of the game.

Still, it's free – so you might as well give it a go. Just don't expect to be as captivated as the first time you threw a red bird at some pigs.

Download: Angry Birds Go! for iOS / Android / Windows Phone 8 / BlackBerry OS 10

Have you played the new Angry Birds? What do you think? Let us know in the comments.