I recently played a game at letsplaychess.com in which my opponent made a number of bad captures. This enabled me to obtain a quick victory. My opponent was Padkoos of the United Kingdom. In this game, he played white. I now provide the moves of the game along with my commentary.
1. h4 e5
My opponent's move is unusual. More common opening moves are d4 and e4 which aim to control the centre.
2. d4 exd
3. Bf4 Nc6
To my surprise, my opponent does not play Qxd4 on his third move.
4. e3 dxe
5. Bxe3 Nf6
6. Bg5 Be7
My opponent has developed only one piece, his bishop. I have developed three. He is clearly behind in development.
7. Bxf6 Bxf6
This capture by black is a mistake. My dark-squared bishop now has control of the a1-h8 diagonal.
8. c3 d6
9. Bb5 Bd7
White's pin on my knight is only temporary.
10. Bxc6 Bxc6
This capture by black is also a mistake. My light-squared bishop now has control of the h1-a8 diagonal. Development is also a problem for white. Every piece is on his back rank.
11. f3 0-0
White's last move takes away the best square for his knight. A better move here is Nf3.
12. Qb3 Re8+
13, Ne2 Qe7
If white castles now, he loses his knight on e2.
14. Qd1 Bxh4+
White's queen is forced to retreat. I increase my control of the dark squares with my last move.
15. g3 Bxg3
Black fails to see that I can capture his pawn because his knight is pinned.
16. Kf1 Bxf3
Now white's knight is pinned and his rook is under attack.
17. Rh3 Bxe2+
18. Qxe2 Qxe2+
White does not want to give up his queen, but if he does not, I capture her on my next move.
19. Kg1 Qf2+
White's move is forced. I see that my next move is mate.
20. Kh1 Re1#
White's move is forced. His knight on b1 never enters the game.
My opponent fails to understand that his early captures give up control of two important diagonals of the board. He also neglects the development of his pieces and leaves his king far too exposed. I take advantage of these factors to force an early mate.