I can blunder M1 and my opponent misses it and next move I checkmate him.
checkmate after a blunder?
I played the pumpkin and was told I made a blunder. The next move I checkmated. How did that happen?
I saved the analysis but where is it?
If you made a blunder, it just means that you think you played a brilliant move which results in an immediate mate next turn when for example the piece can actually be captured.
You checkmated your opponent because your opponent did not find the best available move (in this case, capturing of the piece).

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I saved the analysis but where is it?
https://www.chess.com/analysis/saved
Thank you. But for some reason it's not there. There's only two of them there

Missed win supposed to be blunder https://www.chess.com/analysis/game/live/21024052229

The computer evaluation doesn’t care about the result (winning), only the decision (hanging a piece). Just because your opponent made a worse decision doesn’t make your decision good, it just means you were lucky.
… and people say there is no luck in chess. Pfft.
I played the pumpkin and was told I made a blunder. The next move I checkmated. How did that happen?
I saved the analysis but where is it?