In the competitive market place for games on mobile, unless you’re already a big name in the industry, there is little chance you can charge the customer upfront 15$ for a title, like Square Enix does.
With the tons of free games being released every month, each one craving for attention, the traditional business model of a 1-time sale with a high-price tag is not sustainable for the small studios or indie developers.
Lately most of the games are released as “free-to-play” and Exp3D is one of them.

It’s free to download

Not charging means there’s no entry barrier, leading to more downloads and so more potential customers.
When playing Exp3D, it’s usually quite easy to pass the first level. The second chapter is just a preview, half-way through the level the player will be presented with the dialog below:

The “demo/full version” model

So one of the sources of revenue is the traditional “try free demo / buy full version” model. It is quite similar to what Shogun is doing, including a preview of the stages which are locked. Except that instead of having 2 APKs on Google Play, Exp3D combines the demo and the full version into the same APK. It makes updates much easier, and it also brings all the ratings and comments of users under the same application on Google Play.
In Exp3D the “full version” is purchased as an in-app purchase (IAP), but it’s actually a 1-time purchase: the transaction is saved on Google servers, you can uninstall the game, change phone and still get back your full version status upon re-install.
The fact that you can upgrade directly to the full version from within the game makes it a nicer user experience and you get to keep all the game progress.

Playing for free

You probably also noticed the “Just let me play for free!” button in the previous dialog.
If you manage to collect 100% of the orbs of the previous level you can actually unlock the next chapter and continue to play completely for free.
This is of course very difficult and reserved to the elite of the players. This concept is actually inspired from Wind Up Knight, I liked the idea of giving away the game to hardcore gamers.
Besides it’s important that the player doesn’t hit a wall “pay now or stop playing”. It’s better to provide some way to progress for free so the player doesn’t feel he is obliged to pay.

In-app purchases

Exp3D features a virtual currency: the orbs. There is a limited number of orbs you can earn at each chapter, no “farming” possible.
These orbs can be used to unlock a new chapter, or to upgrade the weapons of the ship. Orbs can be purchased through IAPs by spending some money.
Several packs of orbs can be purchased, the bigger the pack the cheaper the unit price becomes. Purchasing orbs with real money is in no way mandatory to enjoy Exp3D, especially if you bought the full version the orbs you earn for free by playing the campaign are more than enough to clear the game.
But some people like to play in “god mode” and won’t hesitate to build a very powerful ship if you just give them the possibility.

Advertising

At first I was not planning to use any form of in-game advertising: unless you have a huge audience you’ll make only pennies so I figured ruining the game immersion with ads was not worth it.
When I became aware that Exp3D was becoming really popular in China, I wondered about a way to somehow monetize that success.
There was no possibility to charge directly the customers in China so as an experiment I published an update of Exp3D on Google Play: the updated version would display ads when the game was played in China.
A few days later, the APK was already being redistributed on Chinese markets and I started to get some ads revenue.

The breakdown

So how do these sources of revenue compare to each other?
Here is the breakdown:

Advertising represents 20% of my total revenue, but this is essentially thanks to China, my audience in all the other countries taken together is much smaller.
However, this small audience brings more revenue: the “full version” purchases represent 35% of the income, it’s a 2.9$ purchase which is considered “expensive” by today’s standards for a mobile game.
Exp3D being a niche game, players who love the genre are more willing to pay for it.

And the main source of revenue is IAPs which account for almost half of the income.
Exp3D made me realize the importance of not limiting a game to the traditional model of “free demo/full version”. Some players are more than willing to spend money to have a powerful ship, do not prevent them by having a simple one-time purchase! :)

As for the income itself, the money Exp3D brings every month barely amounts to a tiny fraction of the rent I pay for my appartment in Tokyo.
So, no: it didn’t make me rich in case you were wondering. ;)