The EALA development team definitely took an already great game engine (the Unreal Tournament engine, licensed from Epic Games) and poured a ton more cool stuff in. Take a look at a partial list of some of the things they added.
Standing Stones' List of Undying Technical Features
based on Epic Games' Unreal Tournament engine
Gouraud-shading for world geometry
Skeletal animation system (moving lips, models that can morph)