"Duane Barry" is the first of a two-part story, wrapped up in the next episode "Ascension". One can argue that "One Breath" is the third part of the story, although it doesn't feature the character of Duane Barry played memorably by Steve Railsback, as it follows up on the events in "Ascension" and what happens to Scully in that episode.
"Duane Barry" is a great episode on its own. If you took out the ending, which sets up "Ascension" and to a lesser degree "One Breath", it could have been a one-part mythology episode. In fact, the conclusion, with Scully saying "it's almost as if someone was cataloguing him", would have been a chilling climax on its own. Not that I have any problem with this being a multi-part story, given how good "Ascension" is, and the ending to this episode with Duane Barry breaking into Scully's apartment is fine as it is.
This was Chris Carter's first stab at directing. I have no clue if he made any short films before it, but this is the first piece of TV or film which he directed that is available. It's really very good, and he succeeds in creating a really claustrophobic, foreboding atmosphere. The performances are very good, and the surprisingly well-done alien scenes elevate a standard-issue hostage situation to greatness. The excellent script helps, too.
9/10
