keypusher: <Sally Simpson>
Earlier in the game, before ...g5, I was thinking of 5....c6, 6....Qf6, and 11....f6. Not saying the first two are blunders, or even bad, but they just don't like moves a master would make.
I checked the Stockfish engine on the chessbomb website and it disliked both moves, but it hated ...Bf5 even more. Looks like Black just had a bad plan, because presumably he played ...c6 so he could play ...Qf6, and one of the ideas behind ...Qf6 was probably ...Bf5. (Not saying we should always trust the engine, but I think it was right in this case. You don't need a computer to question leaving your king in the center (especially with an open e-file), leaving your king knight at home, and developing the queen early.)
11....f6 looks so obviously horrible that I assume there must be some crushing refutation to 11....Nf6. Probably 12.Qb3. (11...Nf6 is not even one of Stockfish's top four choices, so it must be quite bad.) Anyway, you have to made some serious mistakes to be reduced to such a move so early. Pawns on h6, g7, and f6? Isn't that the sort of thing you see in "master-crushes-amateur" books?
Agree that Rapport made some wonderful in-between moves, e.g. on move 13 he ignores the fact that Black has captured on c3 and plays 13.Nh4.
Better than ...g5, though certainly not good, is ...h5.
Perhaps better than 25...Rc8 is "Resigns." :-)