What would you play in this position?
4. ...fxe 5. Nc3 Qf7 6. Ne3 c6 7. d3 exd3 8. Bxd3 d5 9. 0-0 and white is SUBSTANTIALLY better. My weak Shredder iphone computer has white at +1.25. Black better be good at defending, because white is about to unleash a supernova-hot attack on black's centralized king.
I would pick up the board and smash it in pieces over my opponent's head...pretending this move sequence had never occured in the first place....
no really....
although I would never play this opening myself as black, I guess in this position
fxe4 ... with (perhaps idle) ambitions to possibly move bishop to c5 in the near future??!!
what other reason black had to play f5 in the first place, otherwise than to capture on e4?
I think the move is fxe4. No, it's not an even game. Latvian players will argue with you for days siting long lines that end with Black bearley able to make a draw, and sure, maybe Black can make a draw that way. Maybe this is not lost just yet, but it is difficult, very passive, and Black had many better tries on move 2.