Hi,
The source code is not available for sale, the APK is the full game for Android. Note that it's not updated, the latest version is only available for PC. I'll update the Android port later next month.
The game is made with Unity and the latest version uses the latest OSVR-Unity SDK.
What do you want to do? This game is here for players only. If you want extra licence or anything else, please contact me by mail.