This is the result of, according to the creator, a "little over the weekend project." I'd love to see what he could do with a whole game.
Upon seeing the new teaser trailer for Assassin's Creed Unity -- specifically, the ballroom shown in the first few seconds -- freelance artist Christian Hecht immediately wanted to imagine what the whole scene would look like... in Unreal Engine 4. The result, after a few days of hard work, is about forty seconds of pure eye candy:
Somebody hire this guy, stat.