The memory game involved memorizing highlighted circles on a grid so even something ostesibly chess adjacent. Magnus did not do particularly well. Even when playing a blindfold sim against 'just' 5 people (the record is 48) he lost track of the positions (slightly) multiple times and would eventually lose 2 of the games on time.
But where Magnus is completely unrivaled is in intuition. His intuition just leads him in a better direction faster than other top players. This is both what makes him so unstoppable in faster time controls, and also so dangerous in obscure openings where he may have objectively 'meh' positions, but ones where the better player will still win, and that better player is just about always him.