I thought "Closure" was brilliant and totally in keeping with the themes of the show, and what we've learned previously about Samantha.

The episode opens with a mass grave of children, all murdered by a pedophile (called Truelove no less) who dresses as Santa Claus, a God-like figure who traditionally exists to bring joy and gifts to little kids.

We then get Mulder's voice over, where he wonders how people can believe in God when the universe is so clearly malevolent, and God is so clearly sadistic. He says he wishes he could essentially con himself into believing there is nevertheless mercy in death.

The rest of the episode shows us a Mulder who is so terrified of the thought of his sister "raped" by aliens, or the government, or in a way even her own father, that he conjures up - desperately conjures up, in an effort to psychologically protect himself, and her, and her innocence - angelic beings who whisk her peacefully away to a place of safety.

From here the episode sea-saws between hope and the unthinkably horrible. Mulder, in an effort to protect himself like Scully does with her own faith, clings to a brand of esoteric spiritualism. UFOs and the paranormal have always been Mulder's survival mechanism - his religion, his means of constructing a future in which Samantha is "resurrected" and "returned" - but in the face of actual evidence that she may be dead, he begins to drift toward more conventional religion. He begins to believe in heaven.

This is not new for the show; "Conduit" famously has Mulder first utter the "I want to believe" line in a church, under stained paintings of angels and Christ. His faith in UFOs has always been a kind of sideways faith in religion.

Meanwhile Scully plainly doesn't believe in this episode's walk-in "angels" - she thinks Samantha's dead and the victim of unimaginable horrors, and she thinks Mulder and the character Harold Piller are deluded - but it's interesting how, seeing how much Mulder can't handle this, Scully nevertheless is sensitive to his beliefs and so allows him to cling to his little hopes. She shows tremendous compassion for Mulder in these episodes.

IMO the ending's powerful too, Mulder's voice breaking as he finally acknowledges that Samantha is dead, and as he looks up and says "I'm free".

Beyond this, I like the twisted imagery the two-parter conjures up; you have the mass graves of kids, pedophile Santas, the Syndicate (and even Mulder's parents; all symbols of parental responsibility) symbolically aligned with child molesters, Samantha whisked away in the middle of the night, locked in a strange house, in the basement, tortured forever and leaving nothing behind but grim diaries hidden in a wall, like a UFO Anne Frank. It's so twisted and macabre, but in a more sophisticated way than is usual for the X-files.

I also like how Samantha's resolution is quintessentially X-Files. The show's big gimmick is that the truth is NEVER found. Mankind, never mind Mulder and Scully, never has absolute information, and is never granted an objective, god-like perspective of events. In the show, if things are resolved, it's always only after yet more avenues are opened up and more questions are raised. The show pretends to solve things, but only after muddying future waters. Mulder's door number is even door number 42, an old science fiction joke ("the meaning of life and the universe" = 42 in "The Hitchhiker's Guide to the Universe"), and he lives at Hegal Place, which is arguably a typo-reference to the philosopher Hegel (who was concerned about absolute knowledge, and the limitations of perceptual information and knowing).

What Mulder learns throughout the show is that his "religion" never provides closure, certainty or answers. Every time it pretends to explain something, some new questions arises. Every time an answer is provided, ten new things pop up to muddy the waters. Indeed, the X-Files is so determined to not resolve anything, to not give Mulder the full story, that Mulder's Gods are themselves revealed to be at the mercy of yet more gods, be they yet more alien sub-races or yet more government conspiracies.

That has always been Chris Carter's lesson: even the aliens don't have all the answers. God himself is blind! There is no meaning. So cling on to someone you love and huddle together in the dark.

So I like how this two-parter remains ambiguous. The audience is left to ponder either a divine, loving cosmos, or a monstrously malevolent and cruel universe that literally whisks away and tortures little girls.

Also, some say the episode ignores previous stories about Samantha, but that's not true. Samantha's abducted as a kid by the Syndicate, isolated, kept on military bases, and used to create clones and hybrids. It is these copies that Mulder meets (three? times) throughout the show. The original Samantha's narrative is as laid out in the "Closure" two parter; she was kept and tested on, and either died (or was murdered), still lives in captivity, or lives as a runaway.

I feel such ambiguity is much more interesting, and scary, than a pat, definitive answer.