Abstract--In this paper, we present a new immersive multiplayer game system developed for two different environments, namely, virtual reality (VR) and augmented reality (AR). To evaluate our system, we developed three game applications--a firstperson-shooter game (for VR and AR environments, respectively) and a sword game (for the AR environment). Our immersive system provides an intuitive way for users to interact with the VR or AR world by physically moving around the real world and aiming freely with tangible objects. This encourages physical interaction between players as they compete or collaborate with other players. Evaluation of our system consists of users' subjective opinions and their objective performances. Our design principles and evaluation results can be applied to similar immersive game applications based on AR/VR.