This paper describes how students use a project management simulation game based on an attack-defense mechanism where two teams of players compete by challenging each other's projects. The project management simulation game is intended to be played by pre-service construction workers and engineers. The gameplay has two parts: a planning part, where the player make managerial decisions about his construction site, and a challenge part where the player chooses between typical problems to occur on the opponent's construction site. Playing the game involves analyzing both your own and you opponent's building project for weak spots. The intention of the project management simulation game, is to provide students with an increased sensitivity towards the relation between planning and reality in complex construction projects. The project management simulation game can be interpreted both as a competitive game and as a simulation. Both of these views are meaningful and can be seen as supporting learning. Emphasizing the simulation aspect let us explain how students learn by being immersed into a simulated world, where the players identify with specific roles, live out specific situations, and experiment with relevant parameters. Emphasizing the competition game aspect we can see how play and competition allow players to experience intrinsic motivation and engagement, as well as thinking strategically about their choices, and hence put attention towards all the things that can go wrong in construction work. The goal of the paper is to investigate empirically how these two understandings influence game experience and learning outcome. This question is approached by qualitative post-game interviews about the experienced fun, competition and realism. Specific attention is given to how the understandings of the experience (for instance as a game and as a simulation) is entangled when the students describe their experience. Using the concepts frame and domain it is analyzed how the students conceptualize and make meaning of the particular educational scenario manifested by the project management simulation game. We take as an outset that students interpret the situations in the project management simulation game as relating to one or several domains, especially the domains competition and simulation. Results suggest that the views of the scenario as a competition and as a simulation do coexist, and that these views merge in a subtle way. The players consider the game to be both a realistic simulation of construction site work and a fun competition in which they try to beat their opponents and these two views do not seem to create cognitive conflicts. In the discussion it is explored how aspects of the design affords this double conceptualization (e.g. the "manage mode" and "challenge mode"), and finally it is discussed how we can explain why the players experience the challenges that they pose on each other as a natural part of the gameplay, but not as a realistic aspect of the game as a simulation.