Pawn and Two: Fritz 12 indicates that Schlechter had the better position at move 24, and recommended the following continuation: (.65) (20 ply) 24.c4 Qf6 25.Qxf6 Bxf6 26.Nc3.
Instead of 25.h4, Fritz preferred (.37) (20 ply) 25.Rhc1 Kg8 26.Ra3, or (.36) (20 ply) 25.Rhg1 Kg8 26.Qg2, with a small edge for White.
After 25.h4, 25...g4 26.Qg2 Ne7, or 25...gxh4 26.gxh4 Qe7, the position would have been about equal.
After 25.h4 Qc8, Nimzowitsch indicated he was threatening to win a piece.
However, after 25.h4 Qc8, Fritz indicates White could have allowed Black to win the piece, and White would still have retained an equal position: 25.h4 Qc8 26.hxg5 Bg4 26.Qg2 Bxe2, (.23) (20 ply) 28.f3 Ba6 29.Kg1 h5 30.Rxh5+ Kg8, (.26) (20 ply) 31.Qd2 f6 32.Kg2 Rf7 33.Rah1, (.13) (21 ply) 33...Qd7 24.b3.
Fritz indicates that 29...f5, was not the winning move. Only after 30.fxg4?? fxe4, was White's game lost.
After 29...f5, Fritz indicates Schlechter could have defended with 30.Ng1! f4 31.gxf4. If then, 31...Nxf4 32.fxg4 Nxd3 33.Qxd3 Qxg4 34.Qd2 Rf6 35.Nxh3 Rf3 36.Qg2 Qxg2 37.Kxg2 Rxe3 38.Ng5+, and the position is equal.
After 30.Ng1! f4 31.gxf4, Black could also try: (-.58) (23 ply) 31...exf4 32.Bd2 Be5, (if 32...Bd7 33.Nxh3 Qd8 34.Kg1, and the position is equal), 33.Be1 Bd7 34.Nxh3 Rg8 35.Bb5 Ne7 36.Bxd7 Qxd7, (-42) (21 ply) 37.Bf2 Qe8 38.Qd3 Rb8 39.Rhg1 Rxg1 40.Nxg1 Qh5+ 41.Nh3 Rg8 42.Rg1 Rxg1 43.Bxg1 Ng6 44.Bf2, with an equal position.