This is an open-source game engine, primarily used for running and modifying games developed with the GoldSrc engine. GoldSrc is the game engine used by Valve to develop classic games like Half-Life. Xash3D FWGS offers a compatible, cross-platform game engine to let users play these classic games on modern systems, mobile devices, and handheld consoles, as well as perform deep modifications and extensions, such as adding touch controls, voice chat, and renderer options.