At GDC 2013, Epic Games released the Unreal Engine 4 „Infiltrator“ demo, running 100% in-engine in real time, showing off UE4’s high-end rendering features as well as the latest tools.
Want to see more? Visit http://www.unrealengine.com/insideunreal.
Official Source: http://www.youtube.com/watch?v=dO2rM-l-vdQ&feature=youtu.be