1.d4
Nf6
2.c4
g6
3.Nc3
Bg7
4.Nf3
d6
5.g3
0-0
6.Bg2
Nbd7
7.0-0
e5
8.h3
Re8
9.e4
exd4
10.Nxd4
a6
11.Be3
Rb8
Black's development looks strange, but is a well known plan in this line. Black is coiling up, preparing to strike out with c5 followed by b5, with an option of flicking in Ne5. A counter-play-at-all-costs strategy, black is even prepared to lose the d6 pawn.
12.Qc2
Ne5
Black could also play c5 and b5 without this move, it seems the knight will simply be kicked by f4 at some point, so essentially black is giving white the moves b3 and f4 for free. But b3 and f4 tend to do white/^s position more harm than good, weakening dark squares and also f4 can leave the e4 pawn weak, unless white can arrange a good time to play e4-e5.
13.b3
c5
14.Nde2
b5
Usually the white queen stays on d1, so once black has reached this setup, white can play f4. Then Ne5-c6 would be impossible due to e4-e5, so black would retreat with Ne5-d7 and white would be able to play Qxd6. This isn't the end of the story though, because black would be able to play b5-b4 winning the e4 pawn. However this does suggest 12.Qc2 is not the best, since now with no pressure on d6, black gets all his play unhindered.
15.cxb5
axb5
It is not clear that this automatic exchange is a good idea, white might simply be exposing his a2 pawn for nothing.
16.Rad1
b4
Black is probably already better, white has two weaknesses on a2 and e4, white should try 17.Nd5 but after 17...Nxd5 18.Rxd5 Be6 black would still have a good position.
17.Nb1?
Quite a bizarre decision, but white was probably dreaming of Nb1-d2-c4 hitting d6 one day. It turns out this is far too slow.
17...Qe7
18.Nd2
Ba6
19.Rfe1
Bd3
20.Qc1
Ra8
There is simply no way to defend a2.
21.f4
Ned7
22.e5
Rxa2!
The pin on the e-file keeps everything under control.
23.Nc3
Desperately white tries to muddy the waters.
23...Rc2
24.exf6
Nxf6
Black goes a piece down temporarily, but after Qa1 bxc3 he wins it back with interest.
25.Bxc5
Rxc1
Trading into an ending, which should be easily winning for black. White makes it easier by losing a piece almost immediately.
26.Rxe7
Rxd1+
27.Nxd1
Rxe7
28.Nf2
Re1+
29.Kh2
dxc5
30.Nxd3
Rd1
0-1