Why didn't the pawn eat the knight?

good but simple

First you should check the position before you upload it here. 
It was game Reshevsky - Ivanovic where black won and mate white like this. 

1. Qh7 Check

Chess.com, you made the puzzle backwards. Black (Ivanovic) won this game. 27...Qxh2! was his sacrifice.

See: http://www.chessgames.com/perl/chessgame?gid=1440942

Note that he could have played the sacrifice a move earlier.

WOW

because it threatens to stop the checkmate with 4...fxg6

easy too easy easiest puzzle

great puzzle.  one of the best that I've seen.

Perty dern gud.

Great puzzle

Nice puzz.

1st 

This is already solved.

What else would black do?

Easy!

the person who said easy must be a retard

nice

one

brilliant mating pattern!!