The texture downgrades (on pop-ins), and resolution... the fps and microstutter(which seem constant in the video)....
If you have other ways to play this, go that root instead imo.
*edit: surprised so many of the youtube comments seem so positive, mostly mentioning it look great for a impossible port.
I didnt myself see it that way.
*edit2: Im not crazy... went to check on PS4 port videos, and that seems drastically better than this.
So like if you have a PS5,PS4/PS4pro,Xbox One X, Series S/X, or a PC able... any of those would be a big improvement in graphics/fluidity.