You are Joe, the courier. It is your job, to deliver all the fashion to all the customers. Sometimes, you have to pick up stuff and return it to the warehouse. However, customers keep ordering more and more — and your bicycle only has room for so many boxes… In this talk we want to tell you how the Elm Architecture empowered us to put the “Elm Street 404” game together. We will give you some insight into the algorithms at play and how we applied functional concepts to the domain of game programming. Some of the challenges we were facing include: implementing a path-finding solution, the random generation of the map and game objects, improving the performance and rendering with WebGL.