Alireza Firouzja failing "easy" puzzle ft. Mohammadreza!

1...g4
2. g3 f3
3. c6 Kf8
4. c7 Kxc7
4. zugzwang

i really don't see any winning move for black.
Edit: king c8 wins

what was the right move?

c8 wins.
Assume the black king only alternates between c7 and c8 from here on, this locks the white king and hence the a pawn in place. If the c pawn pushes it will get taken on c7, and then white is forced to move one of the other pawns.
White g2 to g3 loses after black f pawn takes, and then either white pawn takes. If f pawn takes, g4 wins. If a pawn takes, h4 wins.
White h2 to h3 loses, black just plays h5 to h4 then black has double pressure on g3 and can force white to move here.
White f2 to f3 loses, black just plays h5 to h4 and again has double pressure on g3 which black can force white to move to.
White h2 to h4 loses, black just takes with g pawn and waits for white g pawn to push. White g2 to g4 loses, black takes with h pawn and then takes whichever white pawn pushes next.

Alireza clearly has to work on his endgames 🤣, he should take lessons from magnus

Im actually surprised he didn't get this, how is any pawn move going to help black?

very interesting puzle, the concepts we need to use to solve it are:

1: we are using our king to preven the white king from comming to the b file and opening the way to the pawn promoting, weich means we know that your king needs to stay on c7/c8;

2: we can use the concep of sifting the king from c7 to c8 and c8 to c7 to pass the move to white, eventualy white will have to move the pawns on the a/b/c files;

3: we know need to wait till white is forced to move one of the pawns in the line of fire and capture it, we can do that by keeping the pawn formation in a simetrical formation to the white pawns

king c9 wins

i solved the thumbnail one!

g4 and h4 don't work because of the same reason.

1...g4 2. f3 h4 3.h3 with a blockade
1...h4 2. h3 g4 3.f3
Same position through transposition

By that logic only Kc8 makes sense