Double Fianchetto

HERE is this morning's bottom-board game from round four of the open section of Crewe congress
Barry Hymer (1921/178) - Spanton (1900/168)
Double- Fianchetto Opening
1.g3 e5 2.Bg2 d5 3.d3 Nf6 4.b3 Bb4+!?
I am not sure this really inconveniences White, but it certainly does not hurt Black.
5.c3 Be7 6.Nd2 Nc6 7.Bb2 0-0 8.c4
White's response of 5.c3 to 4...Bb4+!? more-or-less meant he would be obliged to follow up with c4.
8...d4
Black is well-placed to support this advanced pawn.
9.Ngf3 Re8 10.0-0 Bg4 11.h3 Bh5 12.g4!?
This wins the bishop-pair and slightly damages Black's kingside pawn-structure, but at the cost of badly damaging the white kingside pawn-structure.
12...Bg6 13.Nh4 Qd7 14.Nxg6 hxg6
14...fxg6, hoping to use the half-open f file, was a serious alternative, and might have been preferable if a black rook still stood on f8.
15.a3 a5 16.Qc2 Bc5!?
Making it harder for White to move his e pawn.
17.Bc1 Nd8
The f4 square beckons.
18.Rb1 c6
If 18...Qe7, then 19.Qb2, and White still pushes his b pawn.
19.b4 axb4 20.axb4 Bb6 21.c5!?
This surprised me. White gets the c4 square, but Black gets d5, which seems more important.
21...Bc7 22.Nc4 Ne6 23.e3 dxe3?!
Stockfish10 and Komodo10 strongly dislike this, preferring 23...Nd5 24.Bd2 Qe7, when they reckon Black has the upper hand.
24.fxe3 Nd5 25.Bd2 Red8 26.Qb2?!
White prepares to capture the e5 pawn while letting his d pawn fall. This opens the position for his bishops, but Black's pieces become very active. More solid was 26.Rbd1.
26...Nf6 27.Nxe5 Bxe5 28.Qxe5 Qxd3
The engines' 28...Ra2 may be even stronger.
29.Rb2 

Black to make his 29th move

*****
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29...Nd7!
This retreat is powerful because White's queen does not have many squares it can safely go to.
30.Qg3 Nd4?!
Initiating complications, but the engines prefer 30...f6 31.Rc1 Ne5, when the knights are more active than the bishops.
31.Qf2 Ne2+ 32.Kh2 Ne5 33.Re1?
BH must have missed the strength of my reply. White is better after the semi-forcing line 33.Be1 Nc1 34.Rc2 Qa3 35.Rc3 Qa1 36.Bd2! Qb2 37.Bxc1 Qxc3 38.Bb2 Qb3 39.Bxe5 Ra2 40.Qg3 Rdd2 41.Rg1 Qxb4. That is a long line, but most of it is forced, and White emerges with two bishops for rook and pawn.
33...Nc4
The b2 rook has no good square to go to.
34.Rxe2 Nxb2 (0-1, 47 moves)