The Unreal Engine is a widely-used game engine developed by Epic Games. First illustrated in the 1998 first-person shooter game Unreal, it has been the basis of many games since, including Unreal Tournament, Mass Effect, Tom Clancy's Rainbow Six 3: Raven Shield, Tom Clancy's Rainbow Six: Vegas, Red Steel, Gears of War, BioShock, Tactical Ops and so forth. Although primarily developed for first-person shooters, it has been successfully utilized in a variety of genres, including 3rd-person stealth (Tom Clancy's Splinter Cell) and MMORPG (Vanguard: Saga of Heroes, The Chronicles of Spellborn).

Its core written in C++, the Unreal Engine features a high degree of portability, supporting a multitude of platforms including Microsoft Windows, Linux, Mac OS and Mac OS X on personal computers and many video game consoles including the Dreamcast, Xbox, Xbox 360, PlayStation 2, PlayStation 3 and Wii. A great deal of the gameplay code is written in UnrealScript, a proprietary scripting language, and as such large parts of the gameplay can be modified without delving deep into the engine internals. Additionally, as with other middleware packages, the Unreal Engine also provides various tools to assist with content creation, both for designers and artists.

The latest release is the Unreal Engine 3, which is designed around Microsoft's DirectX 9 technology for 32/64-bit Windows and Xbox 360 platforms, DirectX 10 for 32/64-bit Windows Vista, and OpenGL 2.0, OpenGL 2.1 and OpenGL 3.0 for 32/64-bit Linux, Mac OS X and PlayStation 3.

Information from, Unreal Engine