I'm going to give some tips, for that coin, an idea of mine.
1- Each game should have a currency difficulty, the most difficult type games the pyramid reward easier than the Flying.
2 - In the game flying should put 2 things, a solution would be every 100 Score a coin ai did not give a lot of money, or else put a competition who makes the highest Score within 5 or 10 minutes wins an amount.
3 - You win a lot of money and great, but there are people who do not accept wins a lot or bull up the game or the currency, earning% on top of that, So I advise you to put lower reward then you will have no problem.
4 - minimum score to get code is 600, every day +100 or one week +200

I think that's too high, some games are quite difficult like silvercell, it takes me so much time to score 100 and above on that game. Why not just 500? And it can increase +100 every week.