See the feature highlights for the Unreal Engine 3 from GDC 2012.
Unreal Engine - Showcase
This compilation video shows off some of the games built wih Unreal Engine technology.
Allegorithmicís Substance Engine for Unreal Engine 4
Allegorithmic's Substance Engine is now available for all Unreal Engine 4 developers.
Unreal Engine 2014 Gameplay Reel
See the highlights of some of the games built with Unreal Engine technology in this gameplay reel.