Updated: Feb 12
In the Philidor Counter Gambit black counters white’s sacrifice with a counter sacrifice by making the move f5. Both the players have an opportunity to either go for a lead in development or recover the sacrificed pawns in the first instant.
In the Fyfe Gambit and Philidor CounterGambit, white goes for an immediate sacrifice of the white pawn getting only the advantage of immediate piece advances in the game. If black succeeds to foil the immediate piece developments and is able to stabilize the positions then the endgame is much favourable for black and will be able to successfully get and advantage in the endgame. But this move of 3.d4 is not that recommended at a decent level of a chess game.