Games have been used for a long time in teaching and learning. The increasing use of mobile phones makes it possible to link learning outside the classroom with augmented reality (AR). We tested how well the learning of conceptual models can be facilitated by AR games. We present a game designed for the in-service teacher-training workshop to model evolutionary and ecological relationships explicitly. The game, Parasite Race, models the life cycles of three different parasites and allows player to choose between two evolutionary strategies. We tested the game with experienced teachers and revealed a wide range of different gaming strategies: some of the teachers were able to reflect their game strategy and choose appropriate actions right away whereas some of the teachers did not and lost their motivation quickly. We reflect on the experience of programming a simple AR location-based game and on the usability of simple games in the educational context.