The last mistake is decisive...

I blitzed today an Euwe defense, with both players make mistakes in turn.

1.d4 d5 2.e4 dxe4 3.Nc3 e6 4.f3 exf3 5.Nxf3 Nf6 6.Bg5 Be7 7.Bd3 Nd5 !?

8.Nxd5 Bxg5
This was the first mistake. 8...exd5 would have been much stronger

9.Nxg5 exd5 10.Nxf7 (diagram)
My mistake. 10.Qe2+ Qe7 11.Qxe7+ Kxe7 12.00 f6 13.Rae1+ would have been much stronger

10...Kxf7
The third mistake. 10...Qe7 11.Ne5 00 12.Qe2 would have been equal

11.Qh5+ (diagram)
Fourth mistake. 11.00 would have settled matters immediately.

11...g6
final mistake. 11...Ke7 12.Qe5+ would have given black surviving chances.

12.00 black resigns.

Five mistakes in a twelve move blitz game - guess this is only possible in the Blackmar Diemer !