Where is the blunder here?
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13.d4 Rhf8? is the blunder, obviously.
There's Qg6 with a playable game.
I meant where's the blunder before move #7. Rest of the game is blundering garbage, where I just finished out to be polite.
I don't know about "blunder", per se, but 5...Nxd5 is simply a bad move (single ? rather than double ??). 5...Na5 is significantly better, and is one of the reasons why 3.Bc4 is said to be dead equal, and inferior to the Ruy Lopez and Scotch if White wants any advantage at all.