Over the course of the last two years, since it's reveal, we've seen a variety of give and take in regards to XCX; animations smoothed out here, lighting simplified there, geometry added here, alpha removed there, etc.
Almost all games go through this as they are developed, as devs play around with how best to spend their limited rendering budget.
It should also be noted that early showings of the game were heavily edited and controlled to show it in the best possible light, while more recent footage contains more candid uncut gameplay, which will naturally be less flattering.