Why is this a mistake?

What about it?

White to play, capitalize on blacks mistake and secure a crushing advantage.

Black M3 I missed from one of my blitz games.

Flagged with mate in 1 on the board 🥲 I'm furious

Why is this brilliant?

What about it?

I’m just defending the pawn for a pawn push. I don’t see why that’s hard to find. As I’m writing this post I realized that I left my knight hanging 💀 I guess the pawn push is a bigger threat than the knight on the board.

black to move (what to move in this situation ) i lost the match after making a bad move , e4

First blitz game

Shouldn't my king be able to take the knight if the pawn is pinned to the king

Double whammy!

My first underpromotion to a knight and the best move! Better than sex

Double whammy!

Proud of this move