User research has become an important aspect in game development. Especially, user telemetry, i.e., the remote tracking of in-game behavioral data and its subsequent analysis has attracted increased attention in game development and research in the last years. Unfortunately, case studies of game industry-academic relationships concerning the application of user telemetry methods in practice are still sparse. In this case study we report our experiences from employing gameplay visualizations during the development of a commercial mobile game. In particular, we describe the process of the collaboration and discuss developer feedback regarding the visualization itself as well as issues regarding user telemetry integration into the development process.