As in our first game, Black plays aggressively with his knights. So comes the next big decision for White: whether to allow 14. ... NxBd3, giving Black the bishop pair. White can prevent this by playing NxNe5 now, leading to an exchange of queens in the center. Black had already offered an exchange of queens on the previous move; I declined it then, so I decided to decline it here, too.
Rather than react to Black's threat, I decided to threaten something myself.
White must take the knight with the g2 pawn, otherwise the bishop on g5 hangs. This leaves White with doubled f-pawns, which will have a lasting effect on the entire course of the game.
15. gxf3 Qf6e5 16. Bg5f4 Qe5a5
Preliminary positional assessment: a) we are out of book lines and making this up as we go along. b) White has preserved the bishop pair, but at the cost of weakening his k-side. c) Black is actively threatening to break up White's q-side now, too: Black's bishops are strafing the White q-side, and the Black queen & dark-squared bishop are pounding c3, threatening to win at least one pawn there. White must either submit to defending his q-side indefinitely, or come up with a counter-attack. I chose the latter.
17. Bf4xd6 cxd6 18. h4
Rather than go for the undefended d6 pawn immediately, White makes a demonstration against the Black king position. If Black should trade off his dark-squared bishop on c3 and then take the c3 pawn with his queen, White can continue h4-h5, move the king to g2 or h2, depending, and start lining up rooks on an open g- or h-file.
Black avoids the obvious ... BxNc3; 19. bxc3 Qxc3; 20. Qxd6. This would give material equality, but White need not take the d6 pawn, he could pursue the k-side attack with 20. h4-h5, and the absence of Black's dark-squared bishop would make the defence of Black's position problematical. The text move holds Black's weakened d6 pawn, and now threatens White's undefended b2 pawn. Threats and counter-threats.