DS9 anticipates an attack from the Dominion, whilst Garak, Worf, and the other prisoners struggle to survive.
This is a strong conclusion with great character moments and good plot revelations.
Several aspects are memorable, but for me the scenes involving Worf, Martok, and Ikat'ika are the most entertaining, as they portray the warriors code of honour very well and develop the characters nicely.
Garak continues the development made in the previous episode and has a meaningful arc that contributes well to the story.
Everything that happens on and around DS9 is tense and well written. I'm not sure what Gene Roddenberry would have made of all the conflict on display, but it makes for good drama. In particular the Cardassian/Bajoran politics with the involvement of Gul Dukat is a highlight for me.
I think all performances are great, especially Marc Alaimo, Avery Brooks, Andrew Robinson, J. G. Hertzler, James Horan, and Michael Dorn.
Visually it's strong in all scenes for me, with strong cinematography and editing, atmospheric lighting and excellent art direction.
Watch immediately after 'In Purgatory's Shadow' for the full effect.