I think it is not mate if you play 16 Re8.
I agree -- if you play 16 ... Re8 17 Qxh+ Kf8 then you have the f7 square covered with your queen.
But to answer your question, you should evaluate your opponent's threats before making any move. If you had done that, you would've easily won this game. Good luck!
I think 12 ..g6 was a mistake. I was on a roll with chasing the queen, and gaining tempo that I went 1 step too far.
Yea, my mind wasn't even considering protecting that square, since there was such a cramped and immediate mate threat. Should have left the Q in place.
If you really wanted to play defense, you needed to check the white king with your queen on the a1-h8 diagonal. Then you could have slid your queen all of the way back to g7.
From this perspective, your mistake was 17...Nd4+, which blocks that diagonal. Better would have been 17 ...Qc4+. Then when the king retreats to d1 or d2, 18... Qd4+ would have allowed you to safely Qg7 (at the cost of your knight).
As others of said, Re1 would have avoided mate but do you really want to allow the series of Qxh7+, Qh8+, Nh7+ and Bg5+ all in succession, making your king dance for his life? That seems very dangerous.
Jack, the phrase "gain of tempo" is only for a move you wanted to play anyway, like developing a piece or moving a pawn somewhere like E4 or D4. You had no need to play g6, so it wasnt a "gain of tempo" at all.
imirak, yea, I was screwed one way or the other. I should have paid more atetntion to this simple mate comination, is the real answer. And not playing g6 exposing my king
It's not just g6. There will be times that you need to advance your pawns, especially if a coordinated attack on them develops. But just remember that it weakens h6 so you need to be able to deal with the queen going to that square. And knowing that aggressive players will often reflexively move their queens to h6 is often a good way to set a trap early in the game
The real problem is, as you pointed out, that you just didn't see the mate until too late and didn't find a good way to deal with it. No need to kick yourself over that. It's hard to resist the instinct to immediately grab what looks like free material. :)
I didn't look it all of the way through, but having an enemy queen and 2 other pieces pushing your king around on the back rank is something you want to avoid as a general rule. You have to trust that you are not missing something tactically, which is not that difficult to do 4-5 moves ahead.
SCID doesn't do a great job of reacting either.
I was so busy on plundering offense, that I didn't notice the mate threat!