The reference to a "Pyrrhic victory" is a metaphor for a victory that is so costly for the victor that it should hardly be termed a victory. It is a reference to the victory over Rome that King Pyrrhus of Epirus won in 280 B.C. However, he lost so many men that his victory should actually be termed a defeat.
Hacker and Humphrey refer to "Draughts" as pun confusing a written plan with a simple game. For American viewers, "Draughts" is the British name for the board game Americans call "Checkers."