Down Two Exchanges, But Nearly Winning!

GM Andy Soltis and GM Larry Kaufman have recently devoted writings to the dynamic value of the chess pieces.  That is to say, depending on the position on the board, sometimes a minor piece is equivalent to or even stronger than a rook.  This game is a prime example of that.  By Move 25 Black is down a double exchange (!), but he manages to have numerous resources at his disposal to draw, or at some points, even win the game!