15.h4? was bad for White. Black threatens ...Ba4, so White should have played 15.Bc2 to prevent that.
19...f6?! allows White to exchange the inactive Bishop for your active Knight. Move the Knight instead with ...Ng2 or ...Ne6
22...Rc6 looks slow. Perhaps 22...e5 or 22...Qd6 and if 23.Qxb7?? Rb8 24.Qa7 Rxb2 wins for Black
25...e5?! allows White to get counteplay and uncramps his game. Perhaps 25...Rd6 or 25...Rd8 to hold the d5 pawn as the b7 pawn is poison.
26...fxe5 may be OK, but 26...Qxe5 looks better. If 27.Qxb7+, then 27...R6c7 and 28...Bxd2 and 29...d4 should win for Black.
29...d4?! looks weaker than 29...Qc8 or 29...Qe6. After 29...d4, White may be able to draw after 30.c4 and White has some good passed pawns on the queenside. Also 29...d4 allows a good outpost for White's kinght at e4.
30.Be4 may be weak. White could also have played 30.c4 or even 30.Ne4 instead of Be4. 30.c4 may be stronger, followed by 31.b3 with a solid defense on the Q-side.
30...Re6?! allows White to trade off Queens and perhaps draw. Perhaps best is 30...dxc3! and if 31.Bxc6 (or 31...bxc3), then 31...Qd8, threatening ...Qxd2 mate.
31.Qa5?! White should exchange Queens and play 31.Qxe8 Rxe8 32.Nb1 and if 32...dxc3, then 33.Nxc3 and 34.Kc2. Black has to deal with those passed pawns on the queenside.
31...Qc8 protects the Rook on c7, but so does 31...Qb8!, which also threatens 32...Qxb2 and 33...Qxd2 mate.
34.c5?? is the losing move. Black can play 34...Ra1+ as in the game or 34...Rxc5, threatening the Queen first, winning a pawn, and still has mate threats. White should perhaps try 34.Kc2. Now what does Black do? If 34...Bxd2??, then White wins with 35.Qxe5+ Kg8 (35...Kf7 36.Rh7+ will mate) 36.Rh8+. Black has to be careful and not a clear win yet.
I played as black, but feel like I missed some key moves somewhere which would have helped me win faster. What you think?