In this paper, we propose an AR FPS game that allows a player to use physical obstacles for avoiding enemy attacks and defeating enemies. The use of physical obstacles is intended to make the game more fun and immersive. Physical obstacles are classified into static obstacles that do not move and dynamic obstacles that can move. The game design for utilizing real space includes placing game objects in consideration of static obstacles, using physical obstacles as shields to prevent enemy attacks, and using projectiles to attack a player hiding behind obstacles. We prototyped the game using HoloLens2 and conducted a user study using a questionnaire (N = 14). The results showed that the game itself was highly evaluated, as well as the exercise promotion effect by the use of real space.