13.1.dxe6! wins at least a pawn. In the actual game, Black played 1...fxe6 2.Nd5 Qc5 3.Be3 trapping the Queen. Note that 1...axb5 also drops the queen after 2.Nd5 Qc5 3.Be3 Qc6 4.Ne7+ with a royal fork.
14.1.Qg5 Rxe6 (White was threatening 2.Qf6+) 2.fxe6+ Kf8 3.Rf1+ with mate to follow.
15.1.Kd7 (Better than 1.g7 Rg6+ making matters more complicated.) Rg1 2.c6 Rd1+ 3.Kc7 Rg1 4.Kb8 Rb1+ 5.Ka8! and Black resigned.
16.1.Kc4 (With White already up a pawn, winning either of Black's remaining 2 pawns or forcing a queen trade wins for White. Here, 2.Qd5 picking up the a-pawn is the threat.) Qc1+ 2.Kd5 Qc8 (2...Qd1+ 3.Qd4+ or 2...Qg5+ Qe5+ forces the queens off, therefore, this is the only move to protect the g-pawn) 3.Qe7+ Kh8 (Any other move allows 4.Qe6+ with a trade of queens) 4.Kd4! Black is in zugzwang. 4...Kg8 allows white 5.Qg5+ winning the a-pawn. 4...Qf5 allows 5.Qe5+ with a trade of queens. Any other queen move allows 5.Qh4+ followed by 6.Qxg4+. Therefore, Black Resigned.
17.1.Bd5! hxg4 (Threatening mate. 1...Qb5 2.f5! Qb1 {2...Qg5? 3.Nf6+} 3.Nf6+ Kh8 4.Kxg6 and 1...Rc8 2.Nf6+ Kh8 3.Ne8 are both hopeless) 2.Nf6+ Kh8 3.Be4! Qa1 4.Bxa8 Qxa8 5.Kxg6 Qf8 6.Qxf8 Bxf8 7.Nxg4 and White wins.
18.1.Bg4!! (White now threatens mate with 2.Bxe6+ and 3.Qg7#) Nc7 (1...e5 2.Qd5+ Kh8 3.Rf7 Qc5+ {Any other legitimate queen move allows 4.Bg7+ Kg8 5.Rxd7#} 4.Qxc5 Naxc5 5.b4 and White wins a piece; 1...Ndc5 2.Rf8+ Qxf8 3.Bxf8 Kxf8 4.Qh8+ followed by 5.Qxh7+ gives White a won position; 1...Nac5 2.b4 e5 {The knight can't move! 2...Na6 3.Bxe6+ Qxe6 4.Qg7#} 3.Qd5+ Kh8 4.Rf7 and the threat of 5.Bg7+ followed by 6.Rxe7# forces Black to part with his queen) 2.c5! (The d7 knight and the queen are stuck where they are, preventing Rf8 and Qg7 respectively. Neither piece can take the c-pawn: 2...Qxc5 3.Qxc5 Nxc5 4.Rf8#; 2...Nxc5 3.Rf8+ Qxf8 4.Bxf8 Kxf8 5.Qxc5+ winning. Black's position is like a disease. The knight stuck on d7 leaves the bishop stuck on c8, which leaves the rook restricted to a8 and b8.) e5 3.Qc4+ (The other reason for 2.c5!. Black tried to remove the mate threats on g7, but it now leads to other problems.) Kh8 4.Bxd7! (This is necessary to prevent 4...Qxc5+ forcing a queen trade.) Bxd7 5.Rf7! (White will win at least a piece.) 5...Qe8 (5...Be6 and 5...Qe6 both lose a piece after White trades queens.) 6.Bg7+ Kg8 7.Rxd7+! (Removing the only piece that could counterattack White's queen.) Qe6 (7...Ne6 8.Ne4 Qxd7 9.Nf6+ Kxg7 10.Nxd7 and White wins.) 8.Ne4!! and Black resigned as the queen is poisoned due to 9.Nf6#, and the only legitimate way to prevent mate is 9...Rf8, which loses even more material.
19.1.a4!! (1.Rg7+ Kh8 2.Nf8?? lends itself to a draw after 2...Re1+ 3.Kf2 {3.Kg2 loses to 3...Rxa2+ 4.Kh3 Bf1+ with mate next move} Re2+ and the White king can't go to the 3rd rank as 5.Kf3?? Ra3+ 6.Kf4 Rf2 is mate.) 1...bxa3 (The choice is that or a few useless checks.) 2.Rg7+ Kh8 3.Nf8 and Black has the choice of being mated with the knight on g6, or being mated with the rooks via 3...Rxf8 4.Rh7+ Kg8 5.Rcg7#.
20.1.Rh7+ Kg8 2.Rcg7+ Kf8 3.Rxa7! (with the threat of mate) Kg8 4.Rhg7+ Kh8 (4...Kf8 5.Rgf7+!! +-) 5.Rgf7!! and Black Resigned.
21.1.Qc4!! (Both players are very weak on the back rank. White can't take things lightly as 1...Qxe2! was threatened. Here, however, the White queen is immune due to a back rank mate on e8 if either the queen or rook takes White's queen.) Qd7 2.Qc7!! (Same idea as the last move.) Qb5 3.a4!! (3.Qxb7?? loses to 3...Qxe2!) Qxa4 4.Re4! Qb5 5.Qxb7 and Black Resigned since he can't maintain control of e8.
22.1.Qh3!! (Not 1...hxg3?? Rh7 2.Qxh7+ Kxh7 3.b3 {3.g4 Qh3+ =} Qh5+ with a draw by perpetual check.) Rfg7 2.Qc8+ (2...fxg7?? 3.Rxh3 -+) Kh7 3.fxg7 Rxg7 4.Qh3!! (4.h3 prevents the perpetual check, but this is by far better.) Qxh3 5.Rxg7+ Kh8 6.Rg8+ Kh7 7.R1g7+ Kh6 8.Rh8+ Kxg7 9.Rxh3 and White wins.
23.1.e5+! fxe5+ (1...Nxe5 2.Nxe5 fxe5+ 3.Ke4 a5 4.f6 Ke6 5.f7 +-) 2.Ke4 a5 3.Nd2 a4 4.Nxc4+ Ke7 5.a3 bxa3 6.Nxa3 Kf6 7.Nc4 Ne7 8.Ne3 and here Black Resigned as he is, in effect, in zugzwang. With the scattered pawns, one is bound to fall soon.
24.1.Rxf7! Rxf7 2.Qxe6+ Rd7 3.Bg4 and White wins.