Anti-Marshall. the other option for Anti-Marshall is 8.a4 which stops cold any Marshall concepts. The move in the game actually does not but it does take the game out of Marshall theory.
Modern way of Marshall whether you like it or not. It is less researched but it still opens the initiative to black for pawn sacrifice in a way Marshall does.
This is another sideline, I'd say not very successful one as this game will prove again. It has been played by a notable opening theorist Bologan, assuming he knows what he is doing. Dominguez played it as well. Dominguez drew Aronian and Ponomariov in this line, Bologan lost two blitzes to Karjakin and Grischuk.
11. ... Nd4
Black continuation is obviously aggressive. Now white has two options. One is 12. Nxd4 which leads to open game played by Dominguez against Ponomariov and Leko (another Marshall expert) against Yakovenko. Both draws.
The other option and so far less successful one as in the game,
Here we have first new move:
which posses problems to white. Black sacrifices pawn and will spoil white castling pawn structure.
black sacrifices second pawn for the initiative.
18. ...Re8 [this is still home analysis. The option 18. ...Nxc2 leads to a draw by perpetual which is what Tomashevsky did not chose meaning he is confident in his ability to win]
20. Nc5!? [here it would have been interesting to see what Tsky prepared for 20. c3 which seems to be a better move]
20. ...Nd5!? [20. ...Bxc5, 21. Rxc5 Qa1 also leads to a perpetual 22. Qg1 Re2, 23. Qd1 Re6, 24. Qh1 Re2]
[again, it would have been nice to see what Tsky has on 22. c4!? Clearly Kamsky is now interested in drawing this hapless game where he is obviously unprepared]
28. Re3?! [in view what happened in the game 28. Kg2 with perpetual seems more prudent]
30. Qc2!? [there was still time to attempt a draw:
30. b4! Rxb4, 31.Re8 Kh7, 32.Qc2+ g6, 33.Re7 Kg8, 34.Re8 Kh7 and draw repetition. However black could play 30. ... Qc8 or 30. ... Ra8 and avoid the line].
31. b3 Ra8!
and black has more comfortable position.
32. d5!? [desperate attempt to create a "counterpasser" as white realizes his position has become precarious]
34. ...Ra6!? [34. ...Qd6!? could be psychologically stronger: 35. Qd3 h4, 35. f4 Qxf4, 36. Ra4 and even though material is equal the exposure of white king makes it difficult to play for white though this is uncertain double-edge position]
35. b4? [first in series of errors by Kamsky. 35. Qd4 or 35. Re4 is needed for obvious reasons.]
36. Qd4? [now Kamsky changes his mind but it is too late, 36. b5!? was more resilient]
37. Kf1?! [walking into mate but the game is lost either way.]
Trying to avoid Marshall but getting into Marshall-like position for which you are also not prepared, cannot be called successful opening.