1.d4 Nf6 2.c4 g6 3.Nc3 d5 Gruenfeld Defense should not surprise anyone, as Sutovsky, Kamsky's second, is one of the greatest expert in this opening and recently Gata sometimes uses it instead of his favorite Slav.
10... Na5 ( Nobody dares challenge Veselin anymore in the complicated lines after 10... Bg4)
11.Bd3 b6 12.Qd2 e5 13.Bh6 ( At the Russian Team Championship in 2008, van Wely played 13.d5 against Kamsky and lost. The game move is not a novelty but judging by the speed of Veselin's play has to be studied thoroughly during the home preparation.) 13... cxd4 14.Bxg7 Kxg7 15.cxd4 exd4 16.f4 f6 17.e5 Bd7 Developing move that connects Black Rooks on the 8th rank. Now fxe5 is a threat and White should determine the situation in the center. 18.exf6+ Qxf6 19.Ng3 Kh8 The defensive setup of Kamsky seems to be sound. He neutralized the f4-f5 threat and Veselin has to find a way to keep the initiative.
20.f5 gxf5 With Kg7 this would not be possible in view of Nh5+
21.Bxf5 (21.Nxf5 Rae8 22.Rac1 Nc6 and Black manages to coordinate his pieces.)
26... Ne5 27.h3 (27.Ng5 is countered by 27... Ng4) ( or 27.Nf6 Ng6) ( Objectively, the best option seems to be 27.Qd2 d3 28.Qc3 Re8 29.Qd4 Qg7 30.Qd6 keeping the position about equal. Topalov is not the kind of player to retreat and he is still looking for forced lines.)
27... Ng6 Kamsky defends in cold blood. He retained his extra pawn and Veselin should be careful.
28.Rh5 (28.Rh5 Kg8 29.Nf6+ Qxf6 30.Qxh7+ Kf8 31.Rh6 Rc8 32.Rxg6 Rc1+ 33.Kh2 Qf4+ 34.Rg3 Rc3 35.Qg7+ Ke8 36.Qg5 is a possible line leading to about equal Rook ending.)
28... Rg8 This should lead to a forced draw, while Kg8 was offering some chances to fight for more.
29.Nf6 Rg7 30.Nxh7 Rxh7 31.Qxg6 Qe3+ 32.Kf1 Qc1+ 33.Kf2 (33.Ke2 d3+ 34.Qxd3 Rxh5 35.Qd8+ leads to perpetual.)
33... Qd2+ 34.Kg3 Qe3+ 35.Kh2 Qf4+ 36.Kg1 Qc1+ Draw agreed. 1/2