Another GameMaker game I made is a gym training game. This is designed to be a mobile game and used with a touch screen. It was really fun to make because it was a great excuse to research mobile games and I learned a lot about the unwritten rules and strategies inherent to the mobile platform.
One interesting tidbit I learned about the mobile design economy is something called taps-per-minute. It’s an important currency for mobile games because user retention is highly correlated with how often they are tapping the screen. This is just a slice of the fascinating philosophy of mobile game design!