4ror I'm not sure how it reached so many downloads, but I did post the link on some indie game forums. I'm thinking of doing some promotions such as ad placement and even physical promotions. In terms of monetary return, I wasn't aiming for anything and would even settle for $5/month. I just let it do it's thing, but it's more than what I thought could be earned from a free game with no IAPs.
— Creating the top score was so complicated and took a lot of research. I couldn't rebuild it if I tried, but I think this site here was helpful: https://www.scirra.com/tutorials/346/on ... -php-mysql
I should probably implement the GooglePlay leaderboard, and I don't believe there is a way to create your own in-game design for it.