Well, Nf6 gives white a free e5, kicking the knight to h7 (unless black goes BxN, but 8. bxN, Ne4? Qd5!, and black has to lose a the knight to save the mate in f7. It's a well-known mate pattern is position similar to this one. One of the shorter games I've ever seen ended with Qd5 - black resigns! well under the tenth move.

I agree. It is to be said, though, that after the proposed line, white's attack is not doomed. 9... Nxd5, 10. exd5+, Ne7, white has to take very quick action because black is unable to reach its own kingside with pieces other than the B (which is unsupported on its accessible squares), and the rook. White may welcome black kinside castling, in fact, but accurate calculation of black's many defences (o-o - Ng6, f6 - Be5...) must be done. I didn't go into all this, but looked at 11. Qd4, threatening g7. Say black castles. White goes 12. Qg4, a normally forbidden square because of black's lsb, and threatens 13. Bxh6. Black cand defend with Ng6, and white can go on with h4 (threatening 14. h5, if it is a threat at all, since after Re8 I don't see how can white win). If black gets scared of this line, he can play h5 (hoping to divert the queen from g7), hoping is 14. Qxh5 to follow with Nf4!. It kind of forces the exchange 15. Bc1xNf4, BxBf4, 16. Bd3 (threatening mate in h7), Bh6, 17. Ng5, d6 (absolutely necessary, or white will go on d6 himself, avoiding black's lsb to develop for the rest of the game), understanding that white won't have any resource to win after, for example, 18. Bh7+, Kh8, 19. Kxf7+, RxN, 20. QxRf7, 21. KxBh7, 22. Re7, Qg5, 23. QxQ (sadly, the best), KxQ, 24. Rxc7 (Re8+, Kf7, Rh8 can be interesting!). Black hopes to hold drawing chances due to the bishop pair. This is, provided that black finds a way to unravel his last pieces. I won't go into it, or this will be overlong, but it's very interesting. I think black can. This would be the starting position:

Very nice tactic from white!

I've gone through 16. Rad1, based on the fact that it almost forces Bd7, and then white has 17. NxNe7, QxN, 18. RxBe7, Qxd7, 19. Qh5 (unpinning the Q and pressing on f7), Rf8, where white is a little unconfortable to stop the BQ's action on the weak queenside (e.g. 20. Rd1?, Qa4!, where white has to find some defence like the passive 21. Qe2 (all the rest fail, included the promising Rd5, QxB, Rxe5+). But your unlikely N sac was much better! 'fen=r3kr2/ppp2pp1/7p/4pP1Q/q1B1P3/8/PP4PP/3R2K1 w q -'

It seems that black is forced, to the least, to return the knight, with something like Nd4.

Ouch! Good find. That would have hurt...I guess it's better to be lucky than good.

Exactly, the combination introduced by 16.Nf6+ fails by 17...Qd4+, 18.Kh1,Qxc4 Good try though!!!

Wonderful. I remember moves like this in problems and studies, but to find it in a real game is a real satisfaction.