Working on a released free to play title creates a lot of design constraints. Sometimes constraints help to be more creative, but sometimes core elements need to be changed to move forward. In the case of Transit King, a big economy balance and design change had to be made to potentially increase KPIs and create more opportunities for its growth. In this talk we will speak about the process of identifying core problems based on data, evaluating risks and opportunities of potential design changes and see how big alteration in core elements of the game enhanced player retention by 30% and revenue by 40 %