After your webmaster (Ed Eusebi) snapped a photo of the position after Black's 22nd move, NSCF coach Ricardo Perez-Billinghurst, a USCF Candidate Master, pointed out that Black's queen had just moved from e4, and that he had missed an instant win.
Mentally take bsck Black's last move, placing his queen on e4 in your mind. Do you see the winning move?
Black wins with 22...Qg2+! 23.Kxg2 Nf4+ 24.Kg1 Nh3#. The queen sacrifice on g2, setting up the common mating pattern with bishop and knight, is a common combinatorial theme that you should become familiar with.
Black soon redeemed himself for this missed opportunity.
The following position arose after White's 25th move (25.Nc4):
White's idea is that 25...Rxe3 loses to 26.Rxd8+ Ne8 27. Rxe8+ Rxe8 28.Rxe8 mate. But White failed to consider what move by Black?
Black won with 25...Rxd1!:
With the idea that after 26.Qxe8+ Nxe8, White can not play 27.Rxe8 mate because the e1 rook is pinned against the king! An absolute pin can cripple the effect of a battery; this is something to keep in mind.
Wait, there's more!
Ricardo Perez-Billinghurst has reconstructed the entire game and made extensive notes on it. You can play it over here.