Nice Problem
Zigzag
As Per Me This Is The Zigzag
As per me this is hardly a zigzag (edit: well it is a simple one but not as a systematic movement as in #1). It's not even a valid puzzle since white can win with both 5. g5 and 5. Kc2. It is a good demonstration of Grigorievs endgame skills though, as many players might have missed the subtle 4. Kd3!
There are many ways to reply and they may not all be to your liking. Don't refer to your coach but take responsibility for the content of your own posts. Otherwise let your coach post them himself. 4. Kd3 is definitely not a zigzag move, but the whole manoeuvre Kc4-Kd3-Kc2 may be seen as a simple zigzag as your coach probably explained but you didn't understand. The problem is that your diagram is posted as a puzzle for us to solve while it is actually a game fragment. This game fragment is unsuitable for a puzzle as it has more than one solution, a common error on chess.com. The solution given also devaluates the zigzag manoeuver since the moves Kc4-d3 and Kd3-c2 are not contiguous (though they could be) as in zigzag puzzles like post #1.
Indeed, I have been critical, but I saw reason to be critical. In my part of the world that is not the same as being rude.
Edit: You may be a kid and feel that kids shouldn't be talked to like that, but understand that this is not a site for kids. Nobody knows you are and you should expect to be treated as a grown up. If you don't like it, then don't post here or explain who you are. There is a separate kid site on chess.com and it may suit you better.
With the idea of the famous problem "Excelsior" by Sam Lloyd we are here a composition from the same period, of which we should see if Denis Julien would be able to maintain his claim. (See The Loyd 's Excelsior).
The first question is: What piece will be mate?
The second is: How does the white mate in 7 moves?
SOLUTION
Note that it is also possible the variant 6.dxe7+ Kc7 7.exd8=Q#. Personally I think for the most beautiful composition and forced to nice end, Meier could have put a white pawn on b6 in the initial position, so as not to allow 6 ... Rc7.