Sure, but the hyperbole around that fucking matrix demo has to stop.
The only incredible looking part is a fucking cutscene with a limited shooting gallery.
The walking part is nowhere near the level of the gifs that people love to post.
This is from the game and it's pretty awesome.
I think there is a misconception here
the cutscene looked a bit hard to replicate with full controlled gameplay.
That IS gameplay.
We are not in 2K or even 2010 where you had to manually move every object, move every light, add fake effects just for the cutscenes, script every scene, so you have room to do more while there is "no gameplay".
In modern engines, so UE, Unity, in part Cryengine and other stuff from Sony ICE (I don't remember if Decima is ICE or it's just a team inside Naughty Dogs ), you have access to automated "scripts" which, in the end, are all processed in real time like a real game. Most of the job by the CPU is done even when you don't touch the pad.
That's why I find Matrix demo more impressive than the other one with Unity, which was more like an old style demo with "few" routines behind it.
And even in that case, hair physics, muscles physics, light physics, material properties, etc, the CPU has a lot of stuff to do.
EDIT: I just realized someone could say "the demo processed the chase scene in real time and after that there is no need to waste resources on it, so just capture the scene and throw away all the job behind it", which can be true, but I think it's not the case here since the reason why developers do a demo is they need to show the full power. There is no need to fake features to other developers who ALREADY know they could fake a scenes like that.
Always remember the real target of those demos are developers, and they may find impressive some elements that are apparently useless for a gamer.