Herb Gallow’s review published on Letterboxd:
The best way to describe Inferno is confounding. First because if you're looking for a traditional horror narrative, you're not going to really find it, although Dario Argento does seem to remember that he's got a story of sorts in the last ten minutes or so. There's also a temptation to compare this directly against Argento's previous film, Suspiria, and there's enough commonality to begin the task, but not to finish it. I'm usually loath to advise anyone to get high before viewing something, but whatever means you usually employ to get to a place where you can simply be in the moment along with something, do that.
I can't speak to the spirit in which this was meant. I'm not even sure Argento can, as he was laid up with hepatitis for a good deal of production. But based on the product, it seems best consumed as a series of moods and moments. There's not enough comprehensible story to really get invested in a plot. There's some initial threads where people who find out about the existence of The Three Mothers get murdered, but everything leads to a spooky apartment building that's reminiscent a little of H.H. Holmes' murder hotel, and the various unconnected things that occur there. This is, of course, Mater Tenebrarum's (thanks Pixar for making me reflexively think of an unfunny redneck tow truck whenever I hear that) lair, where she doesn't really seem interested in much beyond causing a bunch of weird and malevolent stuff to happen. This is a film where you've got to be content watching things play out for reasons that are not generally clear, to characters that you don't really know.
While a setup like that can come off as amateurish and disjointed, the presence of Mater Tenebrarum in the background does lend just enough thematic scaffolding to make this feel like a singular film. The sinister undercurrents that Argento weaves transform lecture halls and libraries into dangerous catacombs, where knowledge is deadly. That the action takes place amongst books and in living spaces lends this a much different visual signature than the preceding Suspiria. Where the first film was a riot of reds and pinks, this is a quieter blue hue, a much more shadowy and quiet film which induces a much different background feeling than the wanton dance academy. This feeling is what's really sticking with me after watching the film, a strange Witch's Sabbath calm from the still air of after-hours libraries and half-empty reliquary towers. You get the feeling of why someone like the Mother of Darkness, as she's been described anyway, would be into hanging out in this picture.
This is still a Dario Argento movie, though, so you'll get your fill of wild moments. By far the most memorable kill sequence is the antique dealer, first spitefully drowning a wriggling bag of cats, agonizingly slow as he hobbles around on crutches and can't seem to manage the act of submerging. Then he gets his immediate karmic retribution in a tide of starving rats, feasting on him as he flails around in what's presumably the East River or some other foul New York pollution tributary. That was pleasingly gnarly already, but then a hot dog vendor hears his cries of distress and comes sprinting over, only to bury a cleaver in the guy's neck, which is absolutely hilarious in how it comes out of nowhere. If this is the world that Mater Tenebrarum (god damn it) is creating around her, it doesn't seem bad at all to sit a spell and enjoy the antics.