This short paper attempts to show a preview of the process in the development of a sustainability digital game. The purpose of this game is to be available in mobile devices to be used in the classroom so the students can learn about sustainable development and mathematic concepts such as rate of change. The technical strategy for this goal is the use of Responsive Web Design or RWD and the mobile first principles. This technique can speed up the development and maintenance of the project, and it is currently one of the best practices in Web Design.