- In this paper we present Virtual Reality Game Interface (VRGI) that is an interface to conventional 3D desktop first-person-view shooting games. VRGI allows players to play commercial 3D first-person-view shooting games in an immersive environment. We also present a new interaction device the Virtual Simulated Rifle (VSR) that is used to play the games in the Virtual Environment. The VSR replaces the mouse, keyboard and joystick found in a common desktop for playing a 3D game. We conducted an experiment to compare performance between playing a 3D game the conventional way, using a keyboard and a mouse, and by playing the same game in a virtual environment using the VRGI software and the VSR. Experimental results show that playing the same desktop 3D game in a Virtual Environment is harder. However, subjects reported greater satisfaction and enjoyed playing the game more in the Virtual Environment.