On 25.b4, there would follow 25...b6, and there is nothing decisive.
Also not very effective is 25.Kf4 Re8 26.Nxe4 b6 – the black bishop comes out to d7, and Black can defend.

White is trying to weaken the dark squares in the opponent’s camp, so as to organise an attack on the king. But, the weakening of his own construction is something he has not noticed, and Black begins to land counterblows on the light squares:

After 18.Nc3, White has to lose precious time to regain the central pawn: 18...fxe5! 19.Rd1 Be8! (the right square to keep the d5-pawn under attack) 20.Ne4 Rc8 21.Qxe5 Rf5!, and ...Rf5xd5.

This move is not so easy to spot from a distance, when playing 17.e5.

White resigned.