41.Qxh8 was still solid.

There is no immediate mate. But there are so many possibilities it is hard to see the best way to proceed. Sometimes it is better not to give check but to make a move that threatens something. For instance, 42.Re6 threatens mate in two by 43.g4ch and 44.Qg3# or 43.Qf3ch and 44.Qg4#. The defence 42...Nf6 delays but one move, as, after 43.Rxf6, the threat is renewed.

The right move. White now has a quick forced mate wherever the Black king goes.

That's true, and 42...g4 won't help either.

43. Qf7+ Kh6 44. Bxg5+ Kxg5 45. Re5+ Kh4/h6 46. Rh5#

Yeah, this is not mate.

Keep it there since it's confined.

This also works: calling in the reserves.

45. Bxg5 should mate soon, e.g. 45... Nd7 46. Bh6+ Nxh6 47. Qf6+ Kg8 48. Re8+ Rxe8 49. Bc4+ etc.

I can see why Mike said, but I don't agree that 45.Bxg5 is the best move as that mate is hard to find. In fact, I would've missed it. Having said, this move is just as good, and I like it the best since Erika has just won a Rook. Thus, even without mate this is almost as decisive.

Good. Mate is on soon.

Slightly better was 47.Qxb8+ winning the Knight as well.

(!) A fine sacrifice that should lead to mate.

Agreed; clever move.

48.Qe8+ would also be very good and had done the same thing. But, mate is even sooner now.

49. Qe8+ Kg7 50. Qxg6 Kf8 51. Re8#. Notice how this was made possible by the bishop sacrifice.

The mate would've been difficult to find, but I agree that 49.Qe8+ was best.

Agreed. White followed up less decisively that she ought to have done: The mate I found - just as quick - was 49.Qe8ch Kg7 50.Rxg6ch Kh7 51.Qf7#

No. 50.Qe8 was still the way to go, even though it's not check.

(?) White is running out of attackers after 50... Nxe7, though the material edge is still enough to win.

For sure.

After 50...Nxe7, White would have had to start all over again, beginning with 51.Qc3ch (to gain time) and then to bring out the unmoved pieces.

Agreed. I would've taken here.