WAdventure Game Studio
WAllegro (software library)
WJMonkeyEngine
WAssaultCube
WAway3D
WBlender Game Engine
WBlitz BASIC
WCafu Engine
WClanLib
WCrystal Space
WCube (video game)
WCube 2: Sauerbraten
WDelta3D
WId Tech 4
WDim3
WGame-Maker
WGlest
WGodot (game engine)
WId Tech 3
WId Tech 4
WId Tech 4
WId Tech 3
WJMonkeyEngine
WLightweight Java Game Library
WMarathon Trilogy
WMultiverse Network
WOHRRPGCE
WOpenMW
WOpenSimulator
WORX
WPlayCanvas
WQuake II engine
WRen'Py
WSpring Engine
WStarling Framework
WStepMania
WStratagus
WStride (game engine)
WThousand Parsec
WTwine (software)
WWorldForge