It has emerged that up to 40% of new Angry Birds users are opting for additional assistance in Rovio’s insanely popular gaming title, paying for the “Mighty Eagle” in-app purchase which allows users to skip a level should it become too hard.

The impressive stat was outed during a talk by Rovio’s own Mighty Eagle Peter Vesterbacka at the GDC Smartphone Summit, where he gave an insight into how Rovio grew to be one of the most popular game developers in the world today.

The Mighty Eagle in-app purchase costs 99c and can be deployed on a single level that proves too difficult for the Angry Birds player. Rovio has been able to market the additional content item to new users at an App Store level, before users buy the app, helping to increase takeup of the option.

However, many existing users will have downloaded the game before the new feature was released and will have made significant enough progress to not need the additional in-app item.

Vesterbacka noted that whilst Rovio is popular and able to work on its own titles today, the company did underestimate the development cost of Angry Birds (its 52nd game project), working on the game between contracted projects over a total of eight months. This gave the developers and designers “time to polish everything” before it was released.

Apple is credited with helping Angry Birds become the global brand it is today, not just for promoting the game but also because it created the App Store platform, enabling Angry Birds to reach a worldwide audience by taking power away from carriers and the “other people [that] decided on our behalf what was a good game and what was a bad game”.

Rovio hopes to increase the number of people buying the Mighty Eagle in-app purchase, raising it to 50% of all users, providing an update to the feature to make it “more relevant to users”.

Pocketgamer reports that sales of the plush toys have already topped two million units, with Rovio also utilising a partnership with the animated film Rio to increase revenues.