Successful relentlessness: it certainly seems to distinguish him from his contemporaries, although he appears best in short games, too. I’m not familiar enough with the old-timers to know if Carlsen’s—anyone reading this far surely knows—grinding ability is unique.
A mix of Fischer and Karpov. Rip opponents.
Actually I’m a bit surprised that 136 moves is the longest.
Was it all in one day? In Fischer’s day they would seal the move at about the 40th move (so a 136 move game would take 3 or 4 days).
As I recall each player got 2.5 hours, was it? to make 40 moves.