MiCrooks: This game was posted on another site yesterday that has a "game of the day" I like to look at GMChess.com. Problem with the site, is that the quality of the games he picks often are pretty poor, as is the analysis of the position.
In this game, Nimzowitsch does not play well at all. He first decides not to take the draw in hand which is fine, but then right afterwards misses 14...Rxg4 15.Be4 Rxg5 16. Bf3 where he appears to be winning comfortably. Instead, he plays to open the h-file with hxg4.
Then a few moves later he misses 21...Qf5 which picks up the loose Bishop on g5 winning. The Bishop cannot move otherwise Qh5+ and g3 leads to mate. And 22. Bh4 Qh5 23. g3 g5 wins the Bishop as well with the attack still rolling.
Finally, in the position as given, the move made 25. e6 which looks good and in fact wins against Nimzowitsch's reply fxe6 as Rxf5 wins a piece and the game. Bxe6 dropped the Queen, but f6! leads to a complicated position where Black is still playing.
Simply Kg1!! however takes away the Queen's only potential flight square so that an eventual Re3 wins the Queen for a Rook and the game. Thing is, this line which is clearly the best was not even mentioned. The only thing shown was the game continuation.
When you are asked to find the winning line, you normally are not allowed to expect the other side to make blunders. This, unfortunately, is a common theme in the positions given at GMChess.
Hurray for Chessgames.com! Sometimes the positions here are trivial, but rarely are they cooked!