12. d5 is just answered wih Bxd5+ and nothing changed, except black has opened the way for his lsb and is in position to "threat" a Q's exchange soon after, but white will play Qb3 and Rd1... dark skyes...

...all thanks to the semiopen column h.

Qh5.

I would have played 13.Bd5 I think the best move for white.

Dave, I think you may be right!

I can't see the point of 13. Bd5. After c6, the B is again in danger and black is a step further in freeing his pieces. White would answer b4, trapping the N... it gets complicated!

After all, the less tactic of all possible outcomes has been chosen!

Better for white would have been 15.Ne2

I would play 16.Nh5+

But now, it would be answered just by Kg6, and without the lsb nothing more seems to happen...

16...Bxf4

Well, not only that. He supports a N's incursion in e6, and after BxN, QxB. Or the reverse can be imagined: Qe6, BxQ, NxB+, forking black's Q. It doesn't work right now, because the BQ is protected, but can be a resource in the future. b5 comes to mind, if prepared to play the Q to e6. But if b5, Na5, Qd5... In other words: black must take care of white's best piece: Nf4.

This not only deprives white of his best piece, but exploits an overdued pawn (e3) in order to take d4. Moreover, it opens the e column and the g one. Black can have a heavy counterattack here, indicating that the whole plan Qb3 was the wrong one from the beginning. White's idea was probably that black wouldn't have exchanged his best piece for a N, but underestimated the advantages black will get from the exchange.

18.Qb2 would have been better

The disadvantage of the d4 take is that it exposes the black long diagonal, aiming to the BK. It must be exploited as soon as possible. And the Nc1 belongs to e3's guard for the time being.

good move!

Contrary to the "sacred principles", black opens the game by exchanging pawns. In this concrete situation, it helps him more than white, but this is just because white has not put his Q on b2. In that case, the fight for d4 would have leaded the game.

I would play Kh7 getting him off the a1/h8 highway and releasing KR on the g file.

Fantastic game, as most of the ones in which the attacker turns to be the attacked. Full tension here, impossible to predict the outcome. Many plans seem possible. Kh7 is certainly a good move, for the exposed reasons. The played one opens the way to both Bb7, which threatens e3, Qe7, etc. or Ba6, eyeing Bd3. They are very juicy plans for black too.

better would have been 20.Be3

Maybe 20. Ba3, so if gxc5, Bxc5 keeps active the pressure on the Nd4. If e3, f3 can be played.

I would have been tempted to play 20...c5

Very interesting move! It leads to something like this: