Summary: First person perspective games are an important part of the many genres that make up the multi-billion dollar gaming industry. In this article, we present the design and implementation of a 3D first person shooting (FPS) game. Our main contribution is to suggest proper practices rooted in computer graphics and geometry mathematics that we believe should be used when designing 3D FPS games. These practices are level of detail (LOD) based terrain generation and texture mapping based simulation of sky, water and tree. Besides, particle system and billboard technique, character model and animation, mouse pick and sound are also illustrated.