or 36...gxf6 37.♕f7 ♔h8 38.♖xb2? ♖d1#

The black castle looks somewhat defenseless. This suggests 30.Bxf7+ Kxf7 (else drop a pawn) 31.Qg6+:

A) 31... Kg8 32.Nh5

A.1) 32... Qb2 33.Rc2 Rd6 34.Qe4 Qb3 (34... Re6 35.Qxe6+ Bxe6 36.Rxd8+ Bxd8 37.Rxb2 + - [R+P vs b]) 35.Qxe7 Qf7 (35... Re8 36.Qxg7#) 36.Qxd8+ wins a rook and a pawn.

A.2) 32... Bf8 33.Nf6+ Kh8 34.Qh7#.

A.3) 32... Bf6 33.Nxf6+ Kf8 34.Bd6#.

B) 31... Kf8 32.Rxd7

B.1) 32... Rc6 33.Ne6+ Rxe6 (33... Kg8 34.Qxg7#) 34.Rxd8+ Bxd8 35.Qxe6 + - [R+P].

B.2) 32... Qxd7 33.Ne6+ Qxe6 34.Qxe6 wins.

32.Nh5 Qb2
(32...Bf8 33.Nf6+ Kh8 34.Qh7# )

The anti-intuitive 35 ... Kh7! is clearly winning, even after 36 Nc6+. I couldn't find anything clever for W to tip back the scales. More to the point, neither could the engine. Considering B managed to find 32 ... Qb2! and 33 ... Be8! it's surprising he missed the winning move.

Again, the anti-intuitive 34 Qxe8+ looks like the only move to preserves even a modest advantage. I thought about it while I was trying to solve it, but when saw W played 34 Rxd8 and went on to win I thought I must have been mistaken.

1) +1.04 (26 ply) 30.Bxf7+ Kxf7 31.Qg6+ Kg8 32.Nh5 Qb2 33.Rb1 Be8 34.Qxe8+ Rxe8 35.Rxb2 Red8 36.Rxd8+ Bxd8 37.f3 c4 38.e4 Kf7 39.Rc2 c3 40.Kf2 g6 41.Nf4 Bf6 42.Ke2 g5 43.Nd3 h5 44.Be5 Bxe5 45.Nxe5+ Kf6 46.Nd3 g4 47.fxg4 hxg4 48.Ke3

As others have pointed out, white's 34 Rxd8 should have lost the game:

1) -3.75 (24 ply) 34...Rxd8 35.Qxe8+ Kh7 36.Nf6+ Qxf6 37.Qh5 Rd2 38.Qf3 Nd5 39.Rc1 Qxf3 40.gxf3 Nb4 41.Rc4 Nd3 42.h4 Kg6 43.Rg4+ Kf7 44.Ra4 Rc2 45.Ra7 Ke6 46.Ra6+ Kd5 47.Ra7 Bf6 48.Rd7+ Kc4 49.h5 Kc3

Instead white should play Q e8 at move 34:

1) +0.77 (23 ply) 34.Qxe8+ Rxe8 35.Rxb2 c4 36.Rc2 Kf7 37.Be5 Rc5 38.Bd4 Rxh5 39.Bxb6 Rc8 40.Rdc1 Rb5 41.Bd4 Bf6 42.Bxf6 Kxf6 43.Kf1 Rb4 44.f3 Ra4 45.Kf2 Rb4 46.e4 h5 47.Kf1 g5 48.Kf2 g4

But white is on top after black missed 35 Kh7; after R x e8 white has a small but meaningful lead: 1) +0.88 (25 ply) 36.Rxb2 Nd5 37.Rd2 Rd8 38.e4 Nb4 39.Rxd8+ Bxd8 40.Kf1 Kf7 41.Ke2 c4 42.Nf4 Bf6 43.Nd5 Nxd5 44.exd5 Kg6 45.Bd6 Kf5 46.Ke3 h5 47.f3 Be5 48.Bb4 Bb2 49.f4 g6 50.g3 Bf6 51.Kd2 h4 52.d6 hxg3

White keeps an advantage on and off, until the losing move, which is 49 c3. After white's 49 Nf3:

1) +1.10 (23 ply) 49...Nc3+ 50.Bxc3+ Kxc3 51.e4 Kb2 52.e5 c3 53.Ne1 c2 54.Nd3+ Kc3 55.f4 Kd4 56.Kd2 c1=Q+ 57.Nxc1 Ke4 58.Nd3 Kf3 59.f5 Kxg4 60.f6 Kf5 61.Ke3 h5 62.Ke2 h4 63.Kf3 Ke6 64.Kg4 h3 65.Kxh3

But after 49 … c3 its all over:
1) +3.72 (22 ply) 50.Kd3 Bc5 51.Bg7 Bb6 52.Ne1 Nd6 53.Bxc3+ Kc5 54.e4 Kc6 55.f4 Nb7 56.f5 Nc5+ 57.Ke3 Ne6+ 58.Ke2 Ng5 59.Kd3 Kd7 60.Bd4 Bxd4 61.Kxd4 Kd6 62.e5+ Ke7 63.Nd3