Move 3 e6 (white to move)
FEN: rnbqkb1r/pppp1ppp/4pn2/8/2PP4/8/PP2PPPP/RNBQKBNR w KQkq - 0 3
Comment: Black controls the center and pecks away at White's efforts.

Move 3 Nc3 (black to move)
FEN: rnbqkb1r/pppp1ppp/4pn2/8/2PP4/2N5/PP2PPPP/R1BQKBNR b KQkq - 1 3
Comment: This classical approach is aimed at supporting e2-e4, so that he will have three strong pawns (Pc4, Pd4, Pe4) with which to bludgeon Black. Naturally Black shouldn't allow this.

Move 4 Bb4 (white to move)
FEN: rnbqk2r/pppp1ppp/4pn2/8/1bPP4/2N5/PP2PPPP/R1BQKBNR w KQkq - 2 4
Comment: Nimzo-Indian Defense - very popular in this event

Move 4 e3 (black to move)
FEN: rnbqk2r/pppp1ppp/4pn2/8/1bPP4/2N1P3/PP3PPP/R1BQKBNR b KQkq - 0 4
Comment: White recognizes the need for further piece development and begins a slow build-up. There is also the possibility of Ng1-e2 and a2-a3 to force Bb4 away, thus keeping Black cramped.

Move 5 O-O (white to move)
FEN: rnbq1rk1/pppp1ppp/4pn2/8/1bPP4/2N1P3/PP3PPP/R1BQKBNR w KQ - 1 5
Comment: Another plan, the Hubner Variation, is to capture at c3, giving White doubled pawns, and then to play the Black central pawns onto dark squares, thereby replacing (to some extent) the missing dark-square bishop. Some players are reluctant to relinquish the bishop.

Move 5 Ne2 (black to move)
FEN: rnbq1rk1/pppp1ppp/4pn2/8/1bPP4/2N1P3/PP2NPPP/R1BQKB1R b KQ - 2 5
Comment: This Rubinstein Variation aims to force Bb4 to trade for Nc3 or to retreat. Trading gives White a small gain with no cost and the retreat leaves Black without sufficient central control. At least that's the Classical take on this position. I think the first part is right, but the second has to be taken with a grain of salt because Ne2 isn't very good and Bc1 is blocked-in behind Pe3. If Black plays ...d7-d5 or possibly even ...c7-c5 then he's probably alright. It doesn't take a lot of pawn moves to control the center.

Move 6 a3 (black to move)
FEN: rnbq1rk1/ppp2ppp/4pn2/3p4/1bPP4/P1N1P3/1P2NPPP/R1BQKB1R b KQ - 0 6
Comment: Curiously, this pawn appears to be a small prod to Bb4, but later it serves as a threat, inhibiting Black from playing ...b7-b5 because of the danger that Pc7 might be kept backward and weak after b2-b4.

Move 7 Be7 (white to move)
FEN: rnbq1rk1/ppp1bppp/4pn2/3p4/2PP4/P1N1P3/1P2NPPP/R1BQKB1R w KQ - 1 7
Comment: Now Black has a pawn controlling e4, so Ne2 is awkwardly blocking Bf1. On the other hand Bc8 is also blocked by another pawn on a light square. Both players have problems to solve.

Move 7 cxd5 (black to move)
FEN: rnbq1rk1/ppp1bppp/4pn2/3P4/3P4/P1N1P3/1P2NPPP/R1BQKB1R b KQ - 0 7
Comment: This seems to me to be a little premature (it doesn't give Black an opportunity to try to solve his own development problems) and that after this Black isn't worse.

Move 8 Nxd5 (white to move)
FEN: rnbq1rk1/ppp1bppp/4p3/3n4/3P4/P1N1P3/1P2NPPP/R1BQKB1R w KQ - 0 8
Comment: Black can't be cramped by e3-e4 if he's trading off minor pieces! But, is he trading the knight? White will only trade on favorable terms, so perhaps ...exd5 is better.

Move 9 g3 (black to move)
FEN: r1bq1rk1/pppnbppp/4p3/3n4/3P4/P1N1P1P1/1P1BNP1P/R2QKB1R b KQ - 0 9
Comment: He's still maintaing coordination of his pieces and maintaining all the options for his central pawns. This makes it difficult for Black to know how to develop or where to counter. White's position is very safe and yet has good offensive potential.

Move 12 O-O (black to move)
FEN: r1bq1rk1/p1p1bppp/1p3n2/3p4/3P4/P3P1P1/1P1BNPBP/R2Q1RK1 b - - 3 12
Comment: avoiding any King Safety problems after ...Bc8-a6

Move 13 Ne4 (white to move)
FEN: r1bq1rk1/p1p1bppp/1p6/3p4/3Pn3/P3P1P1/1P1BNPBP/R2Q1RK1 w - - 4 13
Comment: I think he's rather trade this knight for Ne2 (should it go to c3) or Bg2, but White will avoid those trades.

Move 14 Bb7 (white to move)
FEN: r2q1rk1/pbp1bppp/1p6/3p4/3Pn3/P3P1P1/1P1BNPBP/2RQ1RK1 w - - 6 14
Comment: Why play here when it's not forced and there's no White bishop which can exploit the weak light squares by Bb5 or Ba6?

Move 15 Rfd1 (black to move)
FEN: 2rq1rk1/pbp1bppp/1p6/3p4/3Pn3/P3P1P1/1PQBNPBP/2RR2K1 b - - 9 15
Comment: threatening Bg2-h3

Move 16 Bb4 (black to move)
FEN: 2rq1rk1/pbp2ppp/1p1b4/3p4/1B1Pn3/P3P1P1/1PQ1NPBP/2RR2K1 b - - 11 16
Comment: neither player's dark-square bishop is very good, but Black's serves a defensive purpose, so White chooses to trade them. The curious part is that ...Bd6xb4 forces a3xb4 when it's not clear how good White's doubled b-file pawns might be.

Move 17 Qf6 (white to move)
FEN: 2r2rk1/pbp2ppp/1p1b1q2/3p4/1B1Pn3/P3P1P1/1PQ1NPBP/2RR2K1 w - - 12 17
Comment: This has the benefit of forcing White to move Ne2 (Bxe4 is terrible) and that allows Black to trade Ne4 for the White knight, rather than for Bb4.

Move 20 Qxd6 (white to move)
FEN: 2r2rk1/pb3ppp/1ppq4/3p4/3P4/P1Q1P1P1/1P3PBP/2RR2K1 w - - 0 20
Comment: After this trade White's pieces are in attacking positions and Black's are defending. Pc6 is obviously weak, but White will need to provoke at least one more weakness (the Principle of Two Weaknesses) if he's to find a way to win.

Move 21 a4 (black to move)
FEN: 5rk1/pbr2ppp/1ppq4/3p4/PP1P4/2Q1P1P1/5PBP/2RR2K1 b - - 0 21
Comment: Apparently he wants to open the a-file with a4-a5xb6 and then he can try to make Pb6 the target.

Move 24 Rdc1 (black to move)
FEN: 5rk1/p1r2ppp/1ppq4/Pb1p4/1P1P4/2Q1P1P1/5PBP/R1R3K1 b - - 4 24
Comment: White has the a-file and still controls c5, but Black has gotten Bb5 to defend Pc6 and guard against Ra6. White probably has to trade-off Bb5 with Bg2-f1, thereby weakening a6, Pb6 and Pc6.

Move 29 Qd7 (white to move)
FEN: 1r4k1/2rq1ppp/Rpp5/3p4/1P1P4/2Q1P1P1/5P1P/2R2K2 w - - 3 29
Comment: Again Black has everything defended, so White has to force another trade, to remove perhaps Rb8.

Move 32 Qf5 (white to move)
FEN: 1rr3k1/5pp1/Rpp4p/3p1q2/1P1P3P/Q3P1P1/5P2/2R3K1 w - - 1 32
Comment: Staying "active" this way isn't really beneficial since there is no weakness Black's queen could exploit by herself.

Move 33 g5 (white to move)
FEN: 1rr3k1/R4p2/1pp4p/3p1qp1/1P1P3P/Q3P1P1/5P2/2R3K1 w - - 0 33
Comment: Should White trade-off Ph4 or advance it? Sometimes it's good to pose your opponent with even the smallest of questions (like this) as the game nears the time control. It seems hxg5 can be answered by ...Qxg5 and then ...h6-h5-h4 might well continue to threaten White's king. On the other hand h4-h5 isolates the pawn and might lose it. Technically it's possible both are good because weakening Kg8 can't be good without greater piece activity in that region to defend.

Move 35 Qa6 (black to move)
FEN: 1rr4k/R4p2/Qpp4p/3p2pP/1P1P4/4PqP1/5P2/2R3K1 b - - 4 35
Comment: threatening b4-b5 to smash the queen-side while Black has his queen terribly misplaced at f3 or h5

Move 38 Qg6+ (black to move)
FEN: 1rr5/R4pk1/6Qp/1Ppp2pP/8/4PqP1/5P2/2R3K1 b - - 1 38
Comment: What I found interesting about the Fritz7 notes is that it continued to "believe" the position was equal or only slightly better for White, but when the White plan came to fruition it suddenly "saw" it was clearly or decisively to White's advantage. It's horizon effect was rather distinctly noticable.