f6 should do a little time delaying white's evil attacks followed by knights. and by a few moves he may regains his position castling long. Maybe its unclear whether white will take advantage his positive positions. Well? What do you think guys?
after g6 white has a three tempo lead in development (a dynamic advantage) and dark square holes to exploit (a static advantage - it wont go away). See the holes on h6,f6,d6,b6. I would play Bf4. Whites best answer would probably be e5, but that just adds d5 to the list of holes...
black may not be materially lost, but he is positionally lost. Even if it takes a while to show it
and by a few moves he may regains his position castling long. Maybe its unclear whether white will take advantage his positive positions. 
must defend the pawn first. what would be your next move? 