That's why people include credits button in the main menu. (people don't really have balls to rebuild your game)
I wanted to learn from your code, Is there any way that we can talk ?
May I ask about the commercial method you have ?
Case you can download any game for free, and it's just about copyright. If you are agree with me then you can add a license to the project.
This will help you get things done much faster + keep earnings.
By the way, I thing in app purchase is the best commercial method cause it's much more in control and also if someone cracks the game then it's not joyful to play.