1. d4 d5 2. c4 Nf6 Marshall Defence.
3. cxd5 White swaps the c for d pawn
e6 if Nxd5 e4 would build a pawn centre with tempo. If Qxd4 white can develop the knight to c3 with tempo, but after Qa5 this line might be OK. e6 leaves the d pawn behind as a gambit
4. dxe6 White accepts the gambit pawn. Black will try to prove a lead in development is worth the pawn. White will try to build a strong pawn centre and hold the gambit pawn while trading down to an endgame
Bxe6 5. Nc3 White threatens e4
Bb4 Black pins the knight stopping the immediate e4. Black has 3 minor pieces out and is ready to castle, but the bishop on e6 is not particularly useful where it stands
6. Nf3 supports the pawn on d4 which was only defended by the queen. White could now play Bd2 without hanging d4
O-O Black possibly castled too soon. Qa4+ was not a threat due to Nc3. Maybe Ne4,Qd3, or c4?
7. a3 Forces the trade of the bishop for knight strengthening whites pawn centre
Bxc3+ The alternative was Ba5 b4 Bb6 e4 leaving white with a big pawn centre and large queenside space
8. bxc3 c5 A nice move, white can't take the offered pawn because after dxc5 Qxd1 Kxd1 whites king is stuck in the centre and the white queenside pawns should all fall
9. e3 Qc2 trying to get e4 in one tempo probably doesn't work here. Here e3 lets the light white bishop out so that the king can castle, and also supports d4. On the downside it makes the dark white bishop ugly for now, and black could try and blockade the centre e.g. c4,B/Qd5,Ne4, but white has an eventual Nd2 and/or f3 available to break it
Nc6 At this point black has three minor pieces developed, has castled and is about to join and centralise rooks ( however the c6 knight will need to go to a5 or e7 to become useful ) . White has an extra pawn, a strong pawn centre, and the two bishops.
10. Be2 Bb5 would be a waste, since the c6 knight wants to move anyway. Be2 provides protection against Bg4 which would get the queen stuck guarding the knight with h3,g4 the only release if it weren't for the light white bishop
Qa5 Threatening the backwards c3 pawn and joining the rooks
11. Bd2 threatens c4 threatening the queen then d5 forking bishop and knight
Ne4 To capture the bishop if c4 is played
12. O-O c4 may still have been possible here, but is complicated. Potential problems include c4 Nxd2 Nxd2 Rd8 d5 Bxd5 cxd5 Rxd5 Ra2 Rd8 and white is trapped in a passive position where the king can't castle and the kings rook is out of play
Rad8 13. Qc2 Again c4 has potential issues e.g. c4 Nxd2 Nxd2 cxd5 ( and black is materially equal but better developed ) Nb3? Qe5 f4?! Bc8 and white looks lost. Here Qc2 gets the queen out of the line of the rook, attacks the knight and joins whites rooks
Bf5 A very nice move lining up the queen with the immediate threat of the ugly but effective Ng3! winning rook for knight
14. Bd3 The alternatives are moving the queen. This move threatens to trade down the knight
Rfe8 Another very nice move. If white now trades Bxe4 Bxe4 Qd1 cxd4 cxd4 and white is on the back rank while blacks pieces can storm the kingside
15. Be1 attempting to keep the two bishops, Be1 instead of Bc1 keeps the black queen lined up. However this move bloacks the rook on f1 in and keeps blacks potential Ng3 threat alive
c4 An excellent move,and only one response avoids losing:
Bxe4 Bxe4 Qb2? Bxf3 with a material advantage or a fatal kingside attack if the bishop is captured
Bxe4 Bxe4 Qe2? Bd3 Skewering Queen and Rook
Be2 Ng3! Qa/b2? Nxf1 Bxf1 b5
Bd2 cxd3 Qxd3 Ng3 forking Queen and Rook
Ne5 Nxe5
g4? cxd3 Qxd3 Bxg4 etc.

16. Bxc4 forced.
Nd6 if Ng3?! Qb3! when:
Nxf1Bxf7+ Kh8 Bxe8 Rxe8 Kxf1 and white is 3 pawns clear
Re7 h/fxg3 and white is a knight and two pawns clear

Here Nd6 forks bishop and queen.

17. Bd3 protecting both forked pieces
Bxd3 White wants to push e4 or c4 and the bishop at d3 supports that aim
18. Qxd3 Qd5 Consistent with trying to stop c4/e4
19. Nd2 Increasing pressure on e4/c4 and threatening f3
Na5 Opening the c file hoping to pressure the backward c pawn. Also eyes b3.
20. f3 Makes e4 unstoppable. Incidentally frees the rook and opens the e1-h4 diagonal
Rc8 Pressuring c4
21. e4 Finally achieving the d4/e4 pawn centre with tempo
Qc6 Threatening c3
22. Rc1 Protecting c3. Possibly better was Bg3 stopping Qxc3 due to this hanging the knight
Ndc4 Blockading c4 and attacking a3
23. Nxc4 White is happy to trade down being two pawns up
Nxc4 24. Rf2 preparing to control a file
b5 cementing the knight on c4. If instead Nxa3? Ra2 Nb5 c4 etc.
25. Ra1 The b-file can't be controlled because of the knight, so white aims to open and control the a-file
Red8 pins the d-pawn
26. Rfa2 Qg6 pins the g-pawn
27. a4 opens the a file:
if black does nothing then axb5
if b6 then axb5 axb5
if bxa4 then Rxa4
b4 doesnt help

Ne5 Threatens the queen, and less obviously f3 due to the pin
28. Qe2 releases the pin on d4 hence threatening the knight, protects f3, and keeps in line with b5
Nd7 29. axb5 Rxc3 30. Bxc3 h6 31. Rxa7 Nf6 32. Ra8 Rxa8 33. Rxa8+ 1-0