csmath: Nothing extraordinary in the opening.
[6. Bxf6 is a major alternative and more solid but this is not what Van Wely usually plays.]
[Van Wely usually plays 10. h4]
[This is Kramnik's recipe which is not a bad example to follow]
14. a4 b4?!
[Strange move at the first sight but it has been seen before, black intentions here are to draw even though it looks like a beginning of a serious fight.]
[Played before by Topalov in 2011 Amber Rapid against Gelfand. It is not an impressive move but it is playable.]
[Topalov played 18. Ba3 which is better move and keeps the game about as balanced as possible.
The idea is:
19. Bf3! Rc8
20. Nd2! Nxd2
21. Bxb7 Nxf1
yet another Topalov's exchange sacrifice with full comp-ensation and a blistering attack.
VW "improvement" is not even remotely as good.]
[18. ...Qc7 is alternative, 19. Nd2 Nxd2, 20. Qxd2 Bxe5 with very sharp game and chances for both sides.]
[black is oblivious to position of his king while spending time to get to c4 pawn. If he had any sense of danger he would have opted for 19. Qxd8 Rxd8, 20. Na3 Bxb2, 21. Nxc4 Bxa1, 22. Rxa1 0-0, 23. c6 Bxc6, 24. f3 Nf6, 25. Ne5 Rc8, 26. Bxf8 Kxf8, 27. Ba6 Ra8, 28. Nxc6 with roughly even ending.]
20. Nxc4 Bxh2
[a wake-up call, black is now better.]
21. Kh1 Rd8
[black plays very logical moves, all these moves could have been expected]
[white still does not understand the danger to his king! 22. Qe1 was forced (with a threat of Ba5). 22. ...Rd4, 23. Ba5 Qf4, 24. Ra3 g4, 25. Rd3! Rxd3, 26. Bxd3 Nxc5, 27. Qe2 with a difficult game for white.]
22. ...Qf4! [he should now but it could already be too late.]
After 25 moves white is strategically lost position even though he still has tactical chances, assuming he would be able to find forced moves. Black played perfectly natural game.
[This is a very strange move that loses outright, it is completely senseless. Clearly 26. Rf1 is forced:
27. Qxg3 Bxg3
28. Bc3 Rf8
29. Na5 Be4
30. Bxa6 f5
and white has bleak chances to try to save the game using his queenside pawns. This is probably lost for white but it offers fighting chance.]
27. Rf1 [A bit too late now since after losing c-pawn white has absolutely nothing to play for.]
The game is here effectively over even though it lasted few more moves.
White has "improved" known game in the way that his "improvement" fails against natural play by black. If this is a home analysis then it is one very poor home analysis.
Van Wely has a reputation of a researcher. His practical play is not as good as his researches are. However in this game, if this is indeed his home analysis, his research failed miserably. While Topalov won his rapid game against Gelfand his opening was not truly exceptional and moreover Van Wely "improvement" was clearly worse than that. On a good note one has to say that So exhibited ability to play natural intelligent moves with ease which testifies to his natural talent.
Topalov's idea is foxy and very tricky, easily to be deceptive and therefore warranted. Van Wely deviation/execution is anything but. If offers quite natural and good moves to black while making it real hard to counter them. Failure to find forced moves during tactical game usually spells doom.