Multiple evidences in the Technology-Enhanced Learning domain indicate that Game-Based Learning can lead to positive effects in students' performance and motivation. Educational games can be completely virtual or can combine the use of physical objects or spaces in the real world. However, the potential effectiveness of these approaches largely depends on the pedagogical design behind the game and to what extent this design is aligned with the requirements of specific educational situations. This paper focuses on puzzle-based games, as a particular strategy that can foster students' problem solving, analytical and memory skills, and on the role of teachers as designers of meaningful games. The paper presents a model (conceptual model and XML binding) to represent puzzle-based games including virtual and physical elements. The expressiveness of the model is shown with several cases to illustrate that the model covers a wide range of significant puzzle-based games. The results from an exploratory user study show that, except two elements of the model that require revision, teachers understand the model and can apply it to solve design tasks.