Uncharted 4 : " There is a world before and a world after this demo "

[Aerys]

 

Its about the second part of the demo behind closed doors :

It's definitely a return to Uncharted 2's sense of scale and action, recreating the thrill of that game's helicopter chase. But on a level so far above that, and what other games have achieved, that it's a literal game changer (I said there'd be hyperbole). The scale, speed, and sheer ambition of the sequence genuinely has the potential to redefine what's possible, drawing a line in this generation's games and not so much raising the bar as firing it into orbit. 

 

http://www.gamesradar.com/extended-uncharted-4-e3-demo/