It was the same story we've seen in games 8 and 9: in a position that was level and headed for a draw, challenger Ian Nepomniachtchi made a major and straightforward tactical error that cost him the game. Magnus Carlsen took advantage (though not as cleanly as he could have, or did, in the previous games), and in doing so has won his fifth World Championship match. Carlsen played well in the match, but aside from his win in the epic sixth game, he mostly played good, solid chess and kept his eyes open for his opponent's blunders.
He thus retains the title he won in 2013 for at least one more year. The final score of 7.5-3.5 sets a modern record, as this is the first time the loser of a World Championship match has been doubled up (or worse) since 1910, when Emanuel Lasker defeated David Janowski by the gruesome score of 9.5-1.5. In that match, however, the difference in strength between the players was obvious, while in this match most of the damage resulted from the first decisive game. The conventional wisdom, embraced by Carlsen himself, is that Nepo's losses in games 8 and 9 - and presumably in today's game 11 as well - would not have happened had the challenger not lost game 6.
So that's it: the match finishes three games ahead of schedule, and Carlsen keeps his title until at least next year. Nepomniachtchi is automatically qualified for next year's Candidates, which will take place in June. A reminder: six of the eight slots have already been filled: Nepomniachtchi, Teimour Radjabov (as compensation for his refusing to play in the last Candidates on account of COVID concerns), Alireza Firouzja and Fabiano Caruana (qualified through the FIDE Grand Swiss), and Jan-Krzysztof Duda and Sergey Karjakin (through the Chess World Cup). The last two spots will come through the FIDE Grand Prix early next year, and you can read up on that here. Nepomniachtchi's prep for this match should at least give him an advantage in preparation over his Candidates opponents. If he does qualify for a second match with Carlsen, let's hope that if he loses again it will be because he forced the champion to show his best chess, and not because of any sort of competitive collapse.
Here's the final game, with brief comments.