Originally posted by Erekose
A couple of things after a quick look:
18 ... Qxd3+ is probably better than Bh3+. He gets his king over to the queenside with Bh3+. You can probably mate him sooner if you keep his king on the kingside, but I don't see a forced mate.
Also 24 ... Nxc2 25 Kxc2 Qxe4+ followed by winning the knight might go faster, too.
I didn't see any really obvious way to finish things, though.
After 18. ... Qd3: 19. Kg1 Qg3 20. Kf1 Nd4 with win of material and if White fails to defend with Rd1 then Black should mate in little while...
After 28. fe5 Ra3 wins material with 29. Ka3 Nc2: being the stem line 30. Kb2 Na1 31. Ka1 Qf3: 32. Kb1 and after Bf1, Bd3 mate follows in a few...If White is still playing.