njchess: Without overdoing it, both GMs play the open for maximum flexibility. White even going so far as to sacrifice a pawn for better piece play on move 7. Black elects to protect the pawn with 8. ... Nb6 and that sets the tone early on. Both players are still in opening preparation through move 12.
Black's 13. ... Rxf3 is a deep move and a bit of a gamble. At this point, Black has little if any piece play and Aronian just exchanged away his most active piece. He is gambling that his minor piece play activity can trump White's rook play in this position. In more concrete terms, he believes that 15. ... Bc6 together with the half open f-file is worth losing a rook.
Rather than countering Black's strategy with center strengthening moves, White pursues tactics which only help Black's position. 15. Qe4? is a poor move, maybe even a blunder from a strategic point of view. In general, when your opponent is leading or blockading with pawns, counter with pawns unless you are prepared to sacrifice material for positional gain. Here, White's queen is unceremoniously pushed out of the center, and really out of the game.
The sequence of move 16 through 19 is also instructive and is really the turning point in the game. White creates threats with his queen and knight to which Black responds with pawn moves that solidify his position culminating in 19. ... d5. The fact that the bishop is cutoff is minor at this point since White cannot penetrate Black's position on the queen-side at all nor can he generate sustained threats king-side without sacrificing more material.
After move 19, the center is effectively locked for the time being and both players now turn their attention fully to the king-side. However, Black now has the initiative since White must first play Nc3. Now, like his queen, White's knight has few good squares to occupy.
After the expected 20. ... Rf8 from Black, White embarks on, in my opinion, a questionable, king-side attack starting with 21. Ne2. The problem I have with Ne2 is that since f4 and h4 are the logical culminations of this sequence, it threatens to open up the center which is disastrous for White. His king cannot stay on g2 if he plays f4. Moreover, the Ne2, Kg2, Rh1, h4 is way too slow. Aronian easily handles this clumsy attack, picking up a pawn in the process.
In all fairness to GM Giri, I'm not sure what to suggest in terms of moves. Clearly, Black has the better position. The focus of his attack is, for now, f3. The strategy for White should be to shore up his position and look for improvements, not unlike Aronian's strategy. Unfortunately, he is saddled with a nearly useless queen, a knight with few possibilities and rooks with no way to get in the game. Nimzowitsch would be proud!
After 25. ... Nxh4+, it is pretty academic. Black starts with probing attacks on the queen-side, playing on White's unconnected rooks. After some cat-and-mouse, as the position opens up, Black infiltrates White's position first with his bishop and then this knight. Throughout, Black's keeps his pieces well coordinated with his knight and bishop leading the attack buttressed by his rook and queen.
By move 34, White is really just marking time. His only threat down the h-file is simply ignored by Black. With White's pieces in disarray, Black decides to open the center on move 37. What follows is an ingenious, crushing sequence by Aronian capped off by the brilliant 41. ... Ne1!!. First, shades of Nimzowtisch, now Capablanca. Great game from Aronian!