Mate in 20: Can you play like Gotham Sub?
The king is trapped; the dark squares are covered by the pawns and the light squares are covered by the knight. Blacks only good moves are to move the bishop back and forth because the e4 knight is pinned and moving the f2 knight would lead to a checkmate. Your mission is to remove the bishop to get black in Zugzwang.
The key is to triangulate the king and make sure not to run into a knight fork that forces white to take and lose control of the c6 and d5 squares. Therefore the king has to take a long journey up to the g6 square.
There are alternatives for some of the moves due to the forum puzzles only allowing one specific line so try a different move even if you get some right ones wrong.