1.e4 e5 2.Nf3 Nc6 3.Bc4 Bc5 4.c3 Bb6! 5.d4 because Black’s Bishop is no longer on c5 and, therefore, not under attack from the white pawn on d4 Black is not obliged to capture!
5…Qe7 Threatening exd4 followed by Qxe4
6.0–0 Nf6 7.d5
Though this drives the Knight back to b8 it also blocks the Bishop’s path to f7. Worse still it also opens the path for Black’s Bishop to f2!!
7…Nb8 8.Bd3 d6 9.h3?
DO NOT make unnecessary pawn moves in front of your castled King.
9…h6! 10.Qe2 g5 11.Nh2 g4!
Black opens lines for his army to capture the white King.
12.hxg4 Rg8 13.Bxh6?
As Irving Chernev says, “DO NOT grab pawns at the expense of development or position!”
14…Nxh2 15.Kxh2 Qh4+ 16.Kg1 Qh3
And here White resigned. The remaining moves are what might have happened had White played on.
17.g3 Rh8 18.Bb5+ Kf8 19.Bh6+ Rxh6 20.Qh5 Qxg3+ 21.Kh1 Rxh5#