Originally posted by Peakite
I was having a look at it last night without much solving it either.
A couple of thoughts I had were:
As stalemate doesn't look an option, white must play Ng4 threatening mate or promotion with check at some point - as soon as black gets to play f1=Q someone has to win.
Bishop move looks unlikely too, I can't see a threat.
So that leaves either ...[text shortened]... show either way as being correct (but did get to see possibilities if black plays both badly).
if 1. g7+, Nxg7 and white quickly runs out of threats.
if 1. gxh7, Kxh7
2. g6+, Kg8 and white quickly runs out of threats.
And I grant that if black played badly enough, this game would end in a draw or possible defeat (if they do something really dumb). But GOOD chess puzzles are designed so that everything is forced after the first move. Not forced as in the other side only has one option to reply with, but forced as in there is a response to every possible move that the opposition could make.