The Source engine is a 3D game engine developed by Valve Corporation. Its unique features include a large degree of modularity and flexibility, an artist-driven, shader-based renderer, accurate lip sync and facial expression technology, and a powerful, efficient and completely network-enabled physics system.

CuervoSp says

9/10 - Agree (5) Disagree (2)

I think is a good game engine and the games with this engine are really nice. ///9 (Sorry about my bad English)