Originally posted by jatyap
The correct answer wouldnt be g4-f6 because your king would be in check if the pawn takes the knight.
It should be:
1. g4-h6! gxh6 (or h2... doesn't matter)
Nope. If 1. Nh6 gxh6 then 2. Qd1+ isn't mate because of Kxg6.
The puzzle is in fact a retro puzzle and fetofs showed that 0. ... f7-f5 must have been the last move so gxf6 e.p (you read gxf6 as Nxf6 which it isn't, a lowercase first letter is pawn takes from the file indicated) is playable and mates in two.
Learn chess notation.