nezhmet: If this game score is correct, black missed a much earlier and shockingly beautiful win. Set up the position after white's 17th move and take a look.
It's really quite nice:
17...cxd4! (17...exd4 also wins, similarly, but Curdo's 17...Rd8? is a bad blunder which doesn't win right away and permits white to fight on, always a dangerous thing to do versus a good player)
18. cxd4 exd4 and now
19. Qxd4 looks plausible but it is crushed by 19...Qb5! winning in all lines.
This is the key motif that returns again and again. Black's octopus-like queen sows destruction in all directions.
The rook hangs and Qh5+ is threatened.
For example, 20. Nd2 defending the rook and now 20...Rd8 21. Qc4 Qh5+ intending 22...Bh3 forces resignation. Black also has the flashier 20...Bf3!! (this position deserves a diagram, I have never seen a tactic like this before) and white goes down the drain. The best he has is 21. Nxf3 Qxf1 with a trivial win for black.
To finish the story of, it only remains to look at 17...cxd4 18. cxd4 exd4 alternatives.
They all lose: 19. Bxd4 loses quickly to our friend 19...Qb5!! (by the way 19...O-O-O in this position also wins quickly with a crushing initiative; black wins material). For example, 19...Qb5 20. Rh1 (ridiculous, but what else?) 20...Qh5+ 21. Kg1 Bxf3 22. Rxh5 Bxd1 and wins.
And the non-capture 19. Bf4 also loses to yes, you've guessed it, our old friend 19...Qb5! and the transfer to h5 is immediately lethal in all lines.