The key gaming engines that I’m aware of are The Unreal Engine and The havoc engine, the Unreal being the most used engine because of how versatile it is in being used for different gaming platforms and the ease it takes to modify gameplay and other aspects thanks to the unrealscript and the developers tools packaged with the engine. The Havok engine on the other hand is a physics engine and allows for almost realistic physics by allowing interaction between objects and or other characters in real time and by giving objects physics based qualities in 3D. The two engines are used widely, mainly due to how cost effective it can be to develop from readymade engines than making one from scratch as well as that it can greatly cut down on development time.
"The engine gods"
Of course though they aren’t the only engines around, some companies have ended up using their own inhouse built game engines. Such games include Dark sector with its evolution engine and Sonic unleashed using the hedgehog engine. The latter shows the advantages of having inhouse technology, the hedgehog engine is a new lighting engine developed to provide much more realistic lighting, it does this by calculating not just the normal aspects of a lighting engine is expected to do but coloured lightmaps for light filtering through transparent objects and reflecting off the world. In a presentation by sega, they were showing off development tools, showing that they may release the engine into third party licensing. Here Sega have a valuable asset at their disposable which they can keep exclusive amping up the company’s repertoire or as I assume they will be doing putting it up for third party licensing, the latter meaning they gain a profit from its use in other games.
"why so blue?"
However the real problem now lies in next gen gaming, as games become much more detailed and realistic, using proprietary engines might not be the best route as new games may need specific engines to work, thus fuelling the need for in house technology.