The Rf1 line brings about defeat much more quickly. Play it out a few moves and you'll see it is much more direct.

The pawn pushes (g4, g5) also seems to give the engines trouble.

Analyze

1q3k2/5p1b/5B1p/3pPPP1/1p1p4/1PbP1Q1P/r7/5RK1 b - -

versus this

q7/5p1k/5Bpp/4Pb2/1p1pNP2/rPbP1Q1P/6PK ...

Thanks for all the posts guys. Very interesting. It appears that Nxg7 is not easy to spot.

My dev version of Stockfish running on a i7-3970X @ 3.5GHz took about 10 minutes to see this line.


Engine: Stockfish 151013 64 SSE4.2 6CPU (4096 MB)
by Tord Romstad, Marco Costalba and Joona

21/28 0:01 0 ...

[Event "nTCEC - Stage 2 - Season 2"]
[Site "http://www.tcec-chess.net"]
[Date "2013.10.14"]
[Round "17.4"]
[White "Hiarcs 14"]
[Black "Gull 2.2"]
[WhiteElo "2999"]
[BlackElo "3061"]
[ECO "C77"]
[Result "1-0"]

1. e4 e5 2. Nf3 Nc6 3. Bb5 a6 4. Ba4 Nf6 5. d3 d6 6. c4 Be7
7. Nc3 O-O 8. h3 Nd4 9. Nxd4 ...

Deep Shredder 9.12 also appears to understand this position.