German developer Fishlabs is known for its high quality 3D games, notably its signature Galaxy on Fire space trader/combat game.

But even it has to deal with the free-to-play model; a subject CEO Michael Schade covered in his GDC Europe talk Galaxy on Fire 2: from triple-A premium on iOS to freemium on Android.

"If you create something that's outstanding, you should be able to charge more for it," Schade argued over the game's price on iOS (ranging from $6.99 to $9.99).

Indeed, the Valkyrie add-on update cost $4.99

"It worked because we were upselling to the original players and getting new users thanks to Apple Game of the Week feature," he added.

More ways to pay

However, even Fishlabs decided it had to deal with in-app purchases, adding the ability to buy in-game credits. These linked into the use of energy cells as the only consumable, while credits can also be used to buy new ships and update them.

The option to add general repair/damage into ships and a second currency were debated but not implemented; the former for concerns about user reaction to the existing gameplay.

The financial result of these changes was that the DLC (Valkyrie add-on) generated 20 percent additional revenue, while the addition of credit packs (IAP) generated 30 percent of revenue.

The future and beyond

All these learnings are now being employed in a new add-on. Called Supernova, this includes as much story as contained in the original game.

It will be priced at $6.99, while the company will also introduce a VIP card that will give you a 50 percent discount on various high-priced in-game items.

This is backed up with vanity ships, which don't provide gameplay advantages, and some high-end ships which have to be unlocked before they can be purchases (using in-game credits, which can also be bought).

The other side

This situation is for iOS versions of the game. When it comes to Android, the situation is rather different.

The initial paid version of Galaxy on Fire 2 wasn't a success, suffering from high levels of piracy, combined with a low conversion rate for in-game purchases.

For this reason, there will be a completely overhauled free-to-play version of game - including the two add-on content packs - for Android.

This is likely to include upkeep consumables such as ship repair, fuel, energy and some forms of ammo, with Fishlabs focusing on alternative monetisation methods such as incentivised video advertising to get around Google Play issues of IAP conversion and support.