Taking advantage of the bishop leaving his post. White only has one move here and leaves both the rook and king with very limited mobility.
14. Rf1e1 Ne7f5
Would be very happy to trade for the bishop, otherwise an outpost on d4 although this would probably end up as a trade.
15. f4 Bh3g4
Pin the knight, many possibilities here, but in the short term makes d4 safe.
16. Nd5e3
White takes up one of many options, electing to threaten the pinning piece.
16... Nf5xe3
Was always going to be happy to trade that knight, so I take the opportunity. Allows me to bring my other knight onto d4 concentrating pressure on his kingside. Have a plan a good number of moves deep at this point.
17. Bd2xe3 exf4 18. gxf4 Nc6d4 19. Be3xd4
White has chosen the lesser of two evils and allows black to take the pawn on f4.
19... Bg7xd4
White's knight is STILL pinned.
20. Kg1h1 Bd4f2
Shifts the rook, now not only is the knight pinned to the queen, but the queen is also committed to defending the knight. The rook is trapped on f1.