Checkmate in Eight

In a recent game of speed chess at chess.com, I checkmated my opponent on my eighth move.  He was Ffoodd of the USA who played black.  This quick checkmate surprised me because my opponent was not a beginner, but undoubtedly the three-minute time limit affected his play.  Here are the moves along with my commentary:

1. e4 c6
2. d4 d5
3. e5 f6

I usually play Nc3 here.  Black attacks my pawn centre.

4. Nf3 fxe5
5. Nxe5 Nf6
6. Be2 h6

Black makes a bad move.  He prevents Bg5 but this is not critical.  He needs to play g6 to prevent Bh5+.

7. Bh5+ g6

All black can do is delay mate.

8. Bxg6#

In this game, my opponent's blunder on his sixth move leads to his quick defeat.  It weakens his kingside so much that he cannot prevent mate.  His exposed king and lack of development are the reason for his rapid downfall.