Ironically, after I spent a fair amount of time analysing the sac, he lost the game on time!

My analsysis was not conclusive, but seemed to give black an overwhelming advantage. As far as I can remember, the opening involved an alekhine advance or an obscure french, but not a main line, or even a named line of either opening.My Bxf2 sac was speculative - I analysed after intuitively playing the sac, not something I would recommend!

I used the safety net technique to make sure I wasn't throwing away a nice game - I could fork his rook and queen, but my main intention was to go on a King hunt.

What happens after 2. Ke2.

A) 2. ... Rf2+ 3. Ke1 Qh5 4. g3 Nxg3 5. hxg3 Qxg3 (Qxh1 6. Kxf2 looks no good for black) 6. Ne2!

B) 2. ... Nf2 3. Qh5 (threatening Qxh7) g6 4. Bxg6 hxg6 5. Qxg6+ Kh8 6. Bg5 Qe8 7.  Bf6+ Rxf6 8. Qxe8+ game over

C) 2. ... Qh5 (threatening mate on f2) 3. Bxe4 Qxe4+ 4. Kd2 Qxg2+ 5. Ne2 Rf2 6. Re1 looks like black is out of firepower.

Of course, I could be missing plenty.

In line B:

After 2...Nf2 3.Qh5 is impossible (the king blocks the path). So 2...Nf2 3.Qe1 Nxh1 4.Nf3. Black's down 2 pieces for a rook and pawn... a bit worse.

Yowch, good catch on the Nf2 line, I guess my visualization still needs some work. :-)