Very cool. Very bizarre. Very "I'm tempted to dig out my PS4 disc, play offline to get no update and see if I can repeat this before the inevitable disappointment of it not being true".
Regardless of how this turns out, its very cool. Either it's real and there's more of Nier Automata than we're aware of, it's fake and someone has very lovingly crafted this which shows impressive amounts of work and we can see what their talents can be used for elsewhere or it's real, but modded in and the tools are much more advanced than we realised and the modding scene can start to explode.
Although on the other hand, this is a Yoko Taro game and between #TeamReal and #TeamFake I'm on #TeamYokoTaroIsPersonallyFuckingWithUs