99.4% accuracy, plus a brilliant move!!
I figured 10...Bc5! had to be correct. It gives up the pawn on g7, but surely it must be poison to open the g-file for black. White brazenly took the pawn, and I made proper use of the newly created channel to white's king.
Recently I saw this theme of drawing the king to g2, then following up with Qg4+ check. It can be a way to force a perpetual check, but in this case, it led to a forced mate.
Questions/comments welcome.