If white should decline the gambit with 1.f4 e5 2.e4, than black can respond with 2...d5 and the Falkbeer Counter Gambit. I use it to transpose to a variation of the King's Gambit again.
1.f4 e5 2.e4 d5 3.exd5 exf4 4.Nf3 Nf6 5.Bb5+ Bd7 6.Bxd7+ Qxd7 and black has a slight advantage while threatening to win a pawn.
Ok I have a question, should black be going for the lines with an early g5 or should he play more solidly?
Personally I like the g5 lines better because they offer the best chances for black. They certainly put white under the greatest pressure.
These lines are after
1.f4 e5 2.fxe5 d6 3.exd6 Bxd6 4.Nf3 g5
The only theory I know is
A sample of the main line
1.f4 e5 2.fxe5 d6 3.exd6 Bxd6 4.Nf3 g5 5.g3 g4 6.Nh4 Ne7 7.d4 Ng6 8.Nxg6 hxg6 9.Qd3 Nc6 10.c3 Qe7 11.Bg2 Bf5 12.e4 0-0-0 13.Be3 Rde8 14.Nd2 f6 15.exf5 Qxe3+ 16.Qxe3 Rxe3+ 17.Kf2 Rhe8 18.Rhe1 Rxe1 19.Rxe1 Rxe1 20.Kxe1 gxf5 and white has a slight edge in the endgame.
Lots of fun for black and it is quite solid 
Yep, that line is about equal. Black will eventually win a pawn back.
Instead of 6.Ne5, 6.Ng5 is a major alternative for white your line.
I like playing Black in the From. Here's a pretty rare line I've played a few times. I know it's not the strongest.
This was in an OTB game I played about 9 years ago vs a 1600. I'm pretty sure this is my quickest ever win in an official tournament game. He resigned after my 10th move.
BTW you mentioned the Falkbeer, that's another favorite of mine where I had some fun games but that's for another thread.
Nice game.
Here is white's alternative to 6.Ne5
For the two pawns black has a strong attack and a powerful position.
I've had 5 e4? played against me, lots of fun....
jontsef, I've not played the From's much (don't face 1. f4 much) but I like the Be7 line and h7-h5-h4 might be a bit caveman, but check out this game. It's not so much about ripping open white as it is just keeping him from completing development.
Yeah, I pulled a quick victory off of an early blunder by white to prevent checkmate. My opponent played 4.g3? an did not stay to watch my demolition of his position.
If white declines the pawn offer with 1.f4 e5 2.d3, black should have no problems.
1.f4 e5 2.d3 exf4 3.Bxf4 Qf6 4.Bc1 Bc5 5.Nf3 d6 and black has a slight advantage.
1.f4 e5 2.d3 exf4 3.Bxf4 Qf6 4.Bxc7 Qxb2 5.Nd2 Na6 and black has a slight advantage.
A simple line for white should he want to avoid the theory, although if the doubled pawns actually outweighs black's bishop pair I am not sure.
I have never seen that line before ogerboy. The reason is that it has a huge hole.
1.f4 e5 2.fxe5 d6 3.e4 Qh4+! 4.Ke2 Qxe4+ 5.Kf2 Qd4+ 6.Ke1 Qh4+ 7.Ke2 dxe5 and black has a significant advantage.
Wait, Nf3 before e4, my bad.
1.f4 e5 2.fxe5 d6 3.Nf3 dxe5 4.Nxe5 (4.e4 Bc5!) 4...Bd6 5.Nf3 is slightly better for white.
A fun option could be 3...Bg4!?
1.f4 e5 2.fxe5 d6 3.Nf3 dxe5 4.Nxe5 (4.e4 Bc5!) 4...Bd6 5.Nf3 is slightly better for white.
That is a just normal From's Gambit accepted -
1.f4 e5 2.fe d6 3.Nf3 de 4.e4 Bc5
I am wondering if white could force through d2-d4 with 5.c3...
Anyway, the position after 4...Bc5 is just a position, black has equalised and both players just play chess. White can follow up with Bc4, d3 Qe2, Be3, Nc3 for example.
Probably slightly better for white, but no more.
Considering the success in the Traxler Discussion thread, I decided to make another one with the From Gambit. This opening does not receive a thorough analysis compared to other openings. Hopefully we can pool our analysis and novelties together to come to a final consensus on the From Gambit.
1.f4 e5