21.? is indeed of insane difficulty K Georgiev vs C Ionescu, 1986  (B40) Sicilian, 53 moves, 1-0 13.? seems as crazy to me K Georgiev vs Kasparov, 1980  (B96) Sicilian, Najdorf, 63 moves, 1-0 I Cheparinov vs Mamedyarov, 2007  (D38) Queen's Gambit Declined, Ragozin Variation, 44 moves, 1-0 Y Wang vs I Cheparinov, 2007  (E87) King's Indian, Samisch, Orthodox, 54 moves, 0-1 A tribute to Fischer Topalov vs Kramnik, 2008  (D44) Queen's Gambit Declined Semi-Slav, 45 moves, 1-0 I Cheparinov vs Ivanchuk, 2005  (A57) Benko Gambit, 44 moves, 1-0 Young Vesko Topalov vs I Miladinovic, 1990  (B46) Sicilian, Taimanov Variation, 28 moves, 1-0 7 games