More proof of the power of going freemium comes from French studio Godzilab.

It's switched its StarDunk online game to free, which after a slow start as a paid game, has seen the total number of downloads go over 1.7 million.

Of course, getting money out of freemium players is another task entirely; something explained by Godzilab's president Thomas Lachartre.

Pocket Gamer: Why did you decide to go freemium?

Thomas Lachartre: Mostly to have the game played by more players. StarDunk is a game which takes its whole dimension when more than a hundred of players are competing.

Before going freemium, only 10-20 people would be playing at any given time. Now that we've switched, it's mostly around 300-500 and there are peaks around 2,000.

What was the thing that most surprised you when you switched from paid to freemium?

We were afraid the iTunes ratings would go to down a lot when switching to free, especially with the remaining iOS 3.1 users and the 'rate on delete' feature. But, surprisingly, it's held up quite well.

The game's rating is still really high and comparable to the rating when the game was paid, which is quite surprising for a free game.

How are you monetising your audience?

This is where we made a few mistakes.

First we decided to monetise the contests by limiting them and offering a premium version of the game with no contest limitations. Players complained about not being able to play as much as they wanted though, so it wasn't a good choice.

We tried to change this by enabling extra contests every day but it still wasn't ideal. Then we decided to remove the contest limitation and add more adverts. This wasn't well received either as it affected the gameplay experience too much.

So we've just released an update in which we reduce the number of ads and add a new virtual currency to the game, StarPoints.

You can earn these by playing or by buying them if you want to get all the unlockables quicker. It seems a lot of players like this new concept. The revenue is higher and this will probably improve the game's addictiveness too.

How helpful was using the Plus+ network in terms of promotion and IAP?

We are only using Plus+ as the social platform with achievements and leaderboards. We are not using the cross promotion service. Ngmoco mostly uses it to promote its own games.

What plans do you have to continue to support Stardunk?

We have some more ideas in the pipeline, especially being able to customise your balls, new game modes, and, of course, new themes and balls.

Will you be releasing StarDunk on other mobile platforms?

We are mostly focused on iPhone. If we do a port for StarDunk that would probably be for Android where the freemium model has a good chance of working.

Will all your games be freemium from now on, or do you think there's still a place for paid games?

That's a good question which we are still trying to answer, but for now we don't think we will develop only freemium games.

You can still see companies such as Gameloft and EA releasing full paid games with no ads, so there's still a market for paid games.

Also, we can't think of a great freemium model for our next game, iBlast Moki 2, so it will probably be a paid app.Thanks to Thomas for his time.