18.Ne4
Muzio Gambit
18... Kg6. One thing about the Muzio Gambit that can be suprising is White's initiave persists after a trade of Queens and can really still be enough for a piece, but I think two pieces here is a bit much.

People who dont know the Muzio gambit would find it very difficult to defend
But the question then has to be Why on earth would you as Black play such a potentially weakening move like 3..g5!?? if you had little or no idea of White's (attacking) idea's after doing as such?
Hey, I like to think I am a optomist (at times) so there maybe one or two who will thrash out 3...g5!?? on the strength of knowning very little about it but thats only one or two. Those who play 3...g5!?? generally as a rule of thumb do so because they have some idea that 4.h4! is going to be the most likely reply
I think Tatzelwurm is right to a degree when he said "The Muzio is irrelevant. 4.Bc4 is a poor move (better are 4.h4 or 4.Nc3), and so is 4...g4 (better are 4...Bg7 or 4...Nc6)". He is right 4.Bc4 is a poor move that (and lets face it) relies on Black making an even worse move with 4...g4.
However on whether or not the Muzio-Polerio Gambit is irrelevant I can't say. There will always be people that will be intoxicated by the draw of attempting to win a game of chess from a peice down so they will continue to use what brain matter and computering power they do have to keep perpetuating their addiction while the rest of us sniff the fumes of their tireless work wondering why so much time is spent on a gambit that can be so easily avoided.
HTH

well if Black doesnt play 3...g4 or something else like Nf6 or Nc6 White could play the very powerful d4! stregthening the center at the cost of a tiny pawn

well if Black doesnt play 3...g4 or something else like Nf6 or Nc6 White could play the very powerful d4! stregthening the center at the cost of a tiny pawn
I really don't want to be rude but how can one with such a rating as yours make such a fatuous statement? What you are dearing to suggest is disputed by known established theory.
As early as the 1986 editon of Korchnoi & Zak "King's Gambit" both the Philidor and Hanstein Gambits where given to be better for Black. Even McDonalds 1998 book on the King's gambit and ECO Volume C supports this view.
The simple fact of the matter is 1.e4 e5 2.f4 exf4 3.Nf3 g5 4.Bc4 is best meet by 4...Bg7 or 4...d6 and the potential of d4 is about as powerful as an American playing cricket.
HTH

People who dont know the Muzio gambit would find it very difficult to defend
But the question then has to be Why on earth would you as Black play such a potentially weakening move like 3..g5!?? if you had little or no idea of White's (attacking) idea's after doing as such?
Hey, I like to think I am a optomist (at times) so there maybe one or two who will thrash out 3...g5!?? on the strength of knowning very little about it but thats only one or two. Those who play 3...g5!?? generally as a rule of thumb do so because they have some idea that 4.h4! is going to be the most likely reply
I think Tatzelwurm is right to a degree when he said "The Muzio is irrelevant. 4.Bc4 is a poor move (better are 4.h4 or 4.Nc3), and so is 4...g4 (better are 4...Bg7 or 4...Nc6)". He is right 4.Bc4 is a poor move that (and lets face it) relies on Black making an even worse move with 4...g4.
However on whether or not the Muzio-Polerio Gambit is irrelevant I can't say. There will always be people that will be intoxicated by the draw of attempting to win a game of chess from a peice down so they will continue to use what brain matter and computering power they do have to keep perpetuating their addiction while the rest of us sniff the fumes of their tireless work wondering why so much time is spent on a gambit that can be so easily avoided.
HTH
Mr .Hadron, 3....g5 is the mainline to the King's Gambit Accepted. Other moves are just alternatives.
experto crede