Jerome Gambit: A Curious Move

The following Jerome Gambit (1.e4 e5 2.Nf3 Nc6 3.Bc4 Bc5 4.Bxf7+ ) game contains a curious 8th move for Black that led to a bit of head-scratching for me in my attempt to understand and explain. I have to say that it didn't faze White, however, who managed a checkmate in under a dozen moves. 

mitchcoleborn - TheWabbitEmu

10 0 blitz, Chess.com, 2020

1.e4 e5 2.Nf3 Nc6 3.Bc4 Bc5 4.Bxf7+ 

4...Kxf7 5.Nxe5+ Nxe5 6.Qh5+ Ke6 

7.Qf5+ Kd6 8.f4 Nf7 

A curious move. What to make of it? Was he playing too quickly?

Black usually answers 8.f4 with 8...Qf6 or 8...Qh5+, or retreats his Knight to g6, or tip-toes his King away with 8...Kc6.

So, is 8...Nf7 an oversight, or part of a defensive plan to return material and then offer an exchange of Queens (see Black's next move)?

For the record, The Database has 8 previous games with 8...Nf7, with White scoring 50%.

Also, here is an assessment from one of my games from about 9 1/2 years ago

Sometimes this Knight move both takes the steed out of danger and provides for the defense of the Black King. In this game, that is exactly what it does, but it should not have.

Yet, the position is not simple. Not even ten moves in, and the Jerome Gambit still has its secrets!

White should now take the Knight with 9.Qxf7, threatening to next to take the Bishop after Qd5+.

Black has a tricky counter-attack with 9...Nf6, covering the d5 square. This seems to give away another piece after 10.e5+ Kc6, but pay attention to White's uncastled King: it is unsafe to now grab material and open both the e- and g-files. White's best is 11.d4, instead, when 11...Bxd4 can be answered with 12.Qc4+ Bc5 12.b4. If Black tries 11...Ne4 instead, White can retreat his Queen with 12.Qb3 or try 12.c4, answering 12...d5 with 13.Qxd5+ Qxd5 14.cxd5 Kxd5 15.dxc5 Nxc5.

Black can also defend d5 with 9...c6, when 10.Qxg7 Nf6 11.Qxf6 Qxf6 12.e5+ Qxe5 13.fxe5+ Kxe5 leads, as with 9...Nf6, to an edge for White.

All of this I learned after the game, with the help of Rybka 3 and Fritz 8.

9.Qxf7 

Yes. This is an improvement over earlier play, where every single player of the White pieces avoided capturing the piece. That includes me, twice.

9...Qe7 

No. This should not lead to an exchange of Queens. As noted above, 9...c6 was the proper response. Again, playing too quickly?

10.Qf5 

Definitely, too quickly, but nothing bad comes of it.

10...Nh6 

When in doubt, attack the enemy Queen. Tempting, but in this position Black needed to find a safe space for his King with 10...c6, or at least offer an exchange of Queens with 10...Qe6.

11.Qd5 checkmate