This article discusses opportunities and limitations of using immersive augmented reality (AR) with head-mounted displays for gaming and education in museums. We first report on a prototype application for HoloLens 2 that we developed and tested with 109 museum visitors in a recent project for an exhibition with large animal skeletons. The results show that the feedback from visitors was overall positive, while more steps are needed before it can be implemented in a museum routine. Based on the findings, we discuss hypotheses for the planned further development of the approaches towards game-based learning in the real environment of a natural history museum.