Sally Jane Black’s review published on Letterboxd:
I won't even pretend to analyze this outside the context of the show; I can't imagine this film stands up without that broader context. The strengths of the show carry this - the chemistry between Scully and Mulder, the byzantine mythology, the delightful side characters - while the best parts of being a film come out in the set design at the end. In fact, if nothing else, that's what makes this worth it. Those HR Giger-esque mazes of alien horror and the beautiful reveal of the UFO are worth every twist and turn and frustrating delay. Even in the context of the show, this episode (so to speak) was disjointed at times, feeling rushed despite its length, feeling at times like it was trying to hit certain points in order to get from A to B for the series. But that's easily forgiven in context of the full series.
The main complaint I have here - and for the series - is that it makes no distinction in source material between some of the more dangerous conspiracy theories used as source material and ones that have less weight. FEMA conspiracies have proven fertile ground for right-wing organizing and recent years have shown the unbelievable damage done by vaccine conspiracies (lies), so seeing them referenced in the show and the film is jarring when the bulk of the series is so rooted in the search for truth amidst the lies of the state.
UFOs tend to be dismissed, as far as I can tell, as completely untrue, and the infrequent leaks and press releases from the military or whatever are all fairly transparent appeals for funding different absurd defense contracts (see Space Force), but they're so widely ignored (in no small part because we all have bigger things to worry about). But the series occasionally hits gold (the entire episode about the Cigarette Smoking Man was basically one truth after another). So the lack of distinction between these seems like irresponsible at best and intentional obfuscation at worst.
Still, in terms of scifi horror storytelling, at its best, this show is sublime. As of this writing, I am starting the revival series from 2016, having recently finished the initial run with a friend of mine. While the writing starts to suffer eventually, there are still gems even into the late seasons, and it didn't completely lose me until Duchovny was entirely out of the picture. Returning to this film tonight was a nice reminder of what the film was at its peak, even if this isn't the best example of its peak.