This is the first Star Trek episode where Computer Graphics are used exclusively in battle sequences.
The poem that O'Brien and Bashir quote from on the Defiant bridge as they go into a seemingly suicidal battle, is "The Charge of the Light Brigade" by Alfred Lord Tennyson. The narrative poem details the events of the real-life Battle of Balaclava during the Crimean War in 1854. Britain and France were at war with the Russian Empire, and that battle was one of the bloodiest of the war, and a well-popularized failed military action. 600 British light cavalry were sent to secure guns and artillery abandoned by the Russians, but a miscommunication caused the commander of the brigade to believe their orders were to attack a different artillery group that wasn't yet abandoned, which was a suicide mission for a group of light cavalry (kind of like the 600 outgunned Starfleet ships, without the Klingons and the rest of the Federation, taking on a fleet of Dominion ships twice their numbers in this case). Accounts from the survivors say that most of the men knew it would be a suicide mission, and when they pointed this out to the commander he stated that their duty as soldiers was to obey orders, even if those orders meant certain death. The commander's response is referred to in what is probably the best known line from the poem: "Theirs not to reason why,
Theirs but to do and die". The brigade attacked, but it wasn't long before the men retreated. They suffered heavy casualties, 101 members of the brigade were wounded, 160 killed. The other lines best known from the poem are the ones quoted by O'Brian and Bashir: "Cannon to right of them, Cannon to left of them, Cannon in front of them Volleyed and thundered; Stormed at with shot and shell, Boldly they rode and well, Into the jaws of Death, Into the mouth of Hell Rode the six hundred."
This episode contains the largest battle ever seen in Star Trek, topping The Way of the Warrior (1995), which itself had topped The Die Is Cast (1995).
Gul Dukat leaves makeup on Sisko's baseball after holding it against his lips.
The Prophets' description of Sisko's life as "the game" is a reference back to the series premiere. There, Sisko explains linear existence to the Prophets using a baseball game as a metaphor. They also referred to 'the game' when explaining to Quark why they had taken away Zek's greed in the third season episode Prophet Motive (1995), because he wanted to know the outcome of the game before it was over.