wwall: Or 21...f6 22.Nd6 Bg6 (22...Rxd6? 23.Rxe7 Bg6 24.f5 Bh5 [24...Bxf5?? 25.Re8 mate] 25.g4 and White wins.If 23...Bxb3 24.Nxh8; if 23...Bxf7 24.Rxe7.
If 24.Bxe6+ Kf6 25.Bb3 Ng6 and Black is OK.
Or 25...Kg6 26.Bc2+ Kh6 27.Rxb7 Nxf4.
Or 29.Rg3, and if 29...Rf6, then 30.Rf3+ Kg5 31.Rexf6 Nxf6 32.Rf5+ and 33.Rxf6 wins for White. If 29...Rh8, then 30.Rf3+ Kg5 31.Rf5+ Kg4 32.h3+ Kg3 33.Rf3+ Kh4 34.g3+ Kxh3 35.Bf5+ Rg4 36.Rh6 mate.
If 29...Kg5, then 30.Rg6+ Kf4 31.Rh4+ Ke3 32.Re6+ Kd2 33.Rxd4+ Kxc2 34.Re2+ wins for White. If 29...Rd2, then 30.g3+ Kg4 31.Rg7+ Kf3 (31...Kh5 32.g4+ Kh4 33.Rh6 mate) 32.Be4+ Ke3 33.Bxd5+
Not 30.Rh4+? Kg5, threatening 31...Rf1 mate. Now White has to play 31.Rxe3, then 31...Kxh4.
If 30...Nxg2 31.Re2 (not 31.Kxg2? Rd2+), and if 31...Rg8, then 32.Kf2 Rg4 33.Rh7 Kg5 34.h3 Rh4 35.Kxg2
If 31...Kg4, then 32.Rg6+ Kh5 33.Rxf5+ Rxf5 34.Bxf5
If 32...Rd5, then 33.h4+ Kg4 34.Bxf5+ Kxh4 35.Re4+ Kh5 36.Bg4+ and 37.Rxf8
Or 33.Kxf4 Kxf4 34.Rxf5+ Rxf5 35.Bxf5 Kxf5 36.Kf2 Kf4 37.g3+ wins.
If 33...Rxf3+ 34.Kxf3, threatening 35.g4, winning the knight.
34.g3 Rxf3+ 35.Kxf3 wins the knight, but 34.h4+ is better.