Do you have a video of other 2700+ players failing to do this? I've watched plenty of live tournament coverage, and it doesn't seem a rare skill. Not claiming they do it as well as the best player in the world, and arguably of all time, but this honestly just seems like table stakes at this level of the game. It's literally their job, every day, to study games and understand and recall new theory.

I thought they actively study and memorise their own games, games of players they currently play against, and games of past notable players. Part of that study and memorising is practising playing the game through from start to finish.

It's not like they accidentally memorised them after they see the game once.

Indeed. I'm willing to believe Magnus is one of the best at this (posted this link because I'm a huge fan!), but it's his job and has been since he was a boy, it's not really magic. And it's just demonstrably not the case that he goes into every game knowing every topical line, not does he really need to.

I'm a big Carlsen fan, he's currently the best chess player in the world, but not all grandmasters think Carlsen or the other top 10 are the best in history.

I can't make an informed opinion myself, but I can retell the arguments I've heard used.

In the past, players like Bobby Fischer dominated their peers, winning tournaments by 5 games or more. Today, super grandmasters play 20 moves of prep from memory and agree to a draw. When they get out of prep they don't play as skillfully as players of the past, pre chess engine era. Today super grandmasters put all their attention into opening theory. (I'm retelling the arguments I've heard, these aren't my own opinions)

I will say I much prefer to watch a super grandmaster blitz or rapid game over a classical game. Not that I watch them live, but I see the occasional video of a grandmaster analysing them in a 10-30 minute video.

I don’t think it’s true that studies show players play less skilfully. At the very least papers like this exist:

https://content.iospress.com/articles/icga-journal/icg0012

But I also think that in a metagame with less equality out of the opening and more blunders, skill was more rewarded in the past - so just look at Magnus’s blitz rating to compare. Either way, the fact is this year Magnus _did_ regularly dominate his peers, despite them all having big teams with thousands of CPU/GPU hours of prep behind them. I know Ben Finegold is never going to be convinced but whatever.

There are a few videos from the same channel with exactly that, and they do worse. But we can easily argue why Carlsen should excel at this -- he played WC matches against Anand, and he would have studied all of this as prep.

Sure, although I've seen Carlsen utterly unprepared against opponents countless times as well (and still win). I am just saying I see Jan Gustafsson (admittedly team Carlsen) doing this on air regularly. Anish Giri does it all the time. I've seen Grischuk do it every time he's in a commentary booth.