The game might as well be titled "What shall we worry about today?" as the little things seem to build up for Black, and he suddenly turns over the game.
vlastous - Makaviel , Sandro
Internet, 2017
1.e4 e5 2.Nf3 Nc6 3.Bc4 Bc5 4.Bxf7+
4...Kxf7 5.Nxe5+ Nxe5 6.Qh5+ Ng6
7.Qd5+
The "nudge". I am not sure that it is necessary, or leads to anything more than the direct capture 7.Qxc5 does, but, in my experience it can get Black to take some time worrying "What is he doing?"
7...Ke8 8.Qxc5 N8e7
So - what is going on here?
White has sacrificed a piece for two pawns, and has already moved his Queen three times. He needs development while taking advantage of Her Majesty's options.
Black is ahead in material and development, but his King is stuck in the middle of the board, at least for now. He needs to design a route to safety, when he can then use his advantages.
9.O-O b6
This is a reasonable move, opening up the a8-h1 diagonal for his Bishop - or, as in the game, the a6-f1 diagonal.
Also possible are 9...d6 and 9...Rf8. There are game examples in The Database.
10.Qc3
A small improvement over the retreat 10.Qe3, which I have used in a couple of wins: perrypawnpusher - Lark, blitz, FICS, 2009 (1-0, 59) and perrypawnpusher - jdvatty, blitz, FICS, 2010 (1-0. 28).
From c3 the Queen threatens Black's g-pawn, which is probably enough to cause the defender some anxiety, although in the long run it is probably risky for White to play Qxg7 as long as Black is able to play ...Rg8, with dangerous pressure on the file against White's King.
10...Ba6
Black chooses a different development, attacking White's Rook at f1. Is he worried about the partially open f-file his King will have to cross in order to castle-by-hand? Possibly.
11.d3 Kf7
Guarding the attacked g-pawn and seeking safety.
12.f4 Rf8
Black's move is all part of his plan, but he would have been more prudent to play 12...d6, as will immediately be seen.
13.f5
Awkward. Where is Black's Knight to go? It turns out that White's Queen was also attacking the e5 square.
13...Nh4
Uncomfortable. Unsafe.
Instead, Black could try 13...Nh8, but 14.f6!? would be a troubling answer, winning the Knight on e7.
Stockfish 8 suggests the pragmatic return of the piece with 13...Kg8 14.fxg6 Rxf1+ 15.Kxf1 Nxg6 which Black probably saw, but which he hoped to avoid.
14.Bg5 c5
I don't understand this move. Perhaps it is played to prevent a possible d3-d4 by White? Possibly better was getting a pawn for the piece with 14...Nxg2.
15.Bxh4 Kg8
Well, it looks like Black's King has finally found sactuary.
Not so! says White.
16.f6
This breakthrough works, even with White not fully developed.
16...gxf6 17.Bxf6 Rf7
18.Nd2 Qf8 19.Rf3 Nc6
Black's two developed minor pieces on the Queenside are out of the action and largely irrelevant.
White now has a brutal attack on the g-file.
20.Rg3+ Rg7 21.Rxg7+ Black resigned
Black will have to give up his Queen (and eventually his Rook, too) in order to avoid checkmate.
