The odd thing is that even understanding that difference, a lot of reviews for Infection are complaining that the film is a bit "confusing", "disjointed", or more charitably, "non-linear". That's to be expected from a viewer who hasn't seen a lot of Asian horror yet. But oddly, those comments are often coming from viewers who seem to love the genre. It's odd, because the genre is characterized by being more non-linear. Compared to the typical U.S. horror film, Asian horror has many of the same differences that European horror from the late 1960s and early 1970s had--it tends to be more surreal and poetic. Rather than a focus on transparent literalism, there is a focus on metaphor, symbolism and dream logic. For anyone familiar with academic philosophy, the difference is reflected there. U.S. horror is equivalent to analytic philosophy, European horror to continental, and Asian horror seems rooted in Zen, Taoism, and so on.
Thus, when you begin watching a film like Infection, you have to expect something different than what you'd expect from, say, Cursed (2004) or Valentine (2001). Although in many ways, Infection is more straightforward and spends more time providing explanations than the typical Asian genre film. It's nowhere near as inscrutable as Charisma (aka Karisuma, 1999) or Chaos (aka Kaosu, 1999), but it's not as transparent as Dark Water (aka Honogurai mizu no soko kara, 2002). Rather, it fits nicely in the middle of the two extremes.
The story is set in a small Japanese hospital. Right from the start, we see that they're having odd problems and things are beginning to get out of control. The hospital is understaffed and quite a few employees do not seem to be as competent as they should be. Meanwhile, we see an ambulance that keeps announcing that it has a patient with a possibly dangerous infection who needs to be seen immediately. We're not sure who they're broadcasting this to. After a while, it becomes clear that they're broadcasting it to no on in particular. Eventually, The ambulance drops off its patient despite protests from a doctor about not being able to handle the case. The patient has a bizarre, possibly fatal infection, and it seems to be spreading.
Although infection makes a fair amount of sense on a literal level, much of the film is meant as an extended, in-depth metaphor for infections, and not just literal biological infections. Director/co-writer Masayuki Ochiai and co-writer Ryoichi Kimizuka stress a phenomenon that's more like meme theory--they're looking at how ideas, or any kind of information or state, starts with a seed that's passed on and evolves/transforms over "generations". Since this is a horror film, a lot of the focus is on how that can go sour.
At the same time, the film works just as well on another level--an unabashed series of cringe-worthy horror set pieces. All of these layers co-exist happily, and most viewers can choose to engage (or not) with the film on any or all of Infection's modes. Like most artworks, you get out of Infection whatever you put into it. That means that this isn't really for passive viewing.
Just as would happen in an infection, or under the various infection-like phenomena that are being symbolized, Ochiai gives us a gradual transformation in style, structure and content. The opening scenes are normally lit, the hospital is well populated with relatively normal folks, and the patients' problems seem only slightly odd. At the very beginning, the film could just as well turn into something of a hospital "soap opera". But imperceptibly from moment to moment (it's only perceptible when you take a step back for a "broad" view), the lighting and color schemes change, first becoming a bit darker, then emphasizing pinks, reds, yellows and finally greens and blues--a color transformation not unlike a minor inflammation leading to bruising, sickness and strong nausea, and finally death.
At the same time, our cast of characters--both medical professionals and patients--gradually dwindles until we're left with only a small core or normality. Infection becomes increasingly claustrophobic, and Ochiai makes a similar transformation in his physical threats--from "hard", external problems, to a gradual getting under the skin, to complete bodily dissolution. At the same time, a ghostly presence becomes more prominent. These kinds of infectious progressions imbue every aspect of the film and are quite ingenious.
But wait--there's more! Ochiai has also given us a mind-bending "rubber reality" film. He makes a philosophical point about color perception early on that ends up being correlated with the changing color schemes on a completely different level, rooted in the mental. This aspect comes as something of a twist near the end, and imply a recontextualization of the whole to that point, although the point may just be the role of the mental in "infections". But just so we don't forget the ultimate aim, Ochiai gives us a small horror set piece tag at the very end that exists only for its own sake.
My love of this film might also have personal roots--just about the only things that disturb me in reality are medical in nature--doctors, hospitals, treatments, sickness, etc., so films like this hit close to my phobias. At any rate, for me, this is one of the best Asian horror films of recent years, right up there with Ebola Syndrome (aka Yibola bing du, 1996), Battle Royale (Batoru rowaiaru, 2000) and Suicide Club (Jisatsu saakuru, 2002). Don't miss it, but go in with the right frame of mind. And bring penicillin.