Black is not familiar with the sharp complications of the King's gambit, and gets mated in 10 moves.

mephisto2    --    bruced8
Veggiecheck  (1)   redhotpawn
2003.09.10     1-0     C30g


1.e4 e5 2.f4 Nc6
Black wants to avoid the gambit lines and declines. More usual ways to decline are Bc5, Nf6 or d6. And of course the Falkbeer counter gambit d5.
3.Nf3 f6?
This move does nothing good defensively, and opens the diagonal h5-e8 as an attack line for white. Better alternatives are: exf4, Bc5, d6, d5, f5!?.
4.Nc3 exf4 5.d4 g5?? (D)

BR :: BB BQ BK BB BN BR
BP BP BP BP :: :: BP
:: BN :: BP ::
:: :: :: BP
:: WP WP BP ::
:: WN :: WN ::
WP WP WP :: :: WP WP
WR WB WQ WK WB :: WR

Black ignores the threat along the h5-e8 diagonal. He needed to develop rather than defending the pawn. Bb4 or Ne7 were good moves.
6.Nxg5! fxg5
Relatively better 6. ... h5 to cover the diagonal. White would play 7.Nh3.
7.Qh5+ Ke7 8.Bc4!
Stronger than 8.Qxg5. White brings another piece into play. That is the essence of the KG.
8...Nf6?? (D)

BR :: BB BQ BB BR
BP BP BP BP BK :: BP
:: BN :: BN ::
:: :: :: BP WQ
:: WB WP WP BP ::
:: WN :: ::
WP WP WP :: :: WP WP
WR WB WK :: WR

The final mistake. He gets mated. White was winning, but it could take a while.
( 8...d5 9.Qxg5+ Kf7 10.Bxd5+ Be6 11.Bxe6+ Kxe6 12.Qf5+ Ke7 13.Nd5+ Ke8 14.Bxf4 Bd6 ( 14...Nxd4? 15.Qe5+ ) 15.Qh5+ Kd7 16.Qg4+ Ke8 17.Qg7 Bxf4 18.O-O Nce7 19.Rxf4 (D)

BR :: BQ BK :: BN BR
BP BP BP BN WQ BP
:: :: :: ::
:: :: WN :: ::
:: WP WP WR ::
:: :: :: ::
WP WP WP :: :: WP WP
WR :: :: WK

and the situation is hopeless for black. )
9.Qf7+ Kd6 10.Nb5# 1-0