Just played through the Redux. I'm very intrigued by the more... well, unexplainable parts of the story, and I'd like to write a bit about supernatural in The Long Dark.
Currently there's very interesting balance of realism and fantasy. Nearly everything could be explained without supernatural elements, but in other hand there's a lot of hints that there's a lot of supernatural in the Quiet Apocalypse.
1. The Aurora
There have been a lot of very well thought theories about the nature of the Aurora, and many details could be explained with our current knowledge of solar flares and coronal mass ejections. While I remember reading some theories about the Aurora's effect on animals, those usually rely on very theoretical concepts or very long-winded explanations. Many things just don't make sense, which makes me more prone to think the Aurora as a supernatural phenomena.
For example, the fact that only carnivores seem to be affected by the Aurora. Characters in the story do notice how behavior of wolves and bears has changed, but there's barely any mention of deer behavior being different. It's also only carnivores who glow in the dark during the Aurora.
The First Flare - the one which wiped out the electronics - is very plausible. However questions like "why do the following auroras bring the electronics back" and "why does the flashlight battery charge during an aurora" do complicate things.
There's something wrong with this guy. I think everyone agrees on that. He is in places he has no reason to be. He knows stuff about Will's journeys he shouldn't have any reason to know. He seems to know much more about the situation than anyone else, but he is cryptic and vague. One of the most damning evidence about his weirdness is in Episode 1 where you can first meet him at the Gas Station and quickly after that down the cliff. How did that one old man get down the cliff, set up a camp and start a campfire in a time that it takes for Will to go from the gas station to the rope and climb down? It doesn't add up, and I feel like it's intentional.
So there's usually three possible explanations for Metusaleh: either he is a supernatural being, a figment of Will's imagination or a badly written plot-hole ridden character. Now there's again the very, well, non-supernatural explanation of Metusaleh being just something Mackenzie imagines in his loneliness. Every time we meet Metusaleh, Will is alone, and no other character interacts with Metusaleh or acknowledges his presence. This would explain how he know so much about Will - because he is literally the same person. Of course this would raise some questions about Will's mental health. Another way of explaining this - the one which does not make Mackenzie insane - is to treat him as a supernatural being, some sort of "manifestation" of nature and the Aurora or some weird hermit mystic with a Biblical name.
3. Jeremiah, Old Bear and the spear
Jeremiah doesn't believe in supernatural or the Spence's story about demon bear. However we as the players have a lot reason to doubt this view. Firstly, the Old Bear seems extremely intelligent. For example, he knocks down Will''s train car but leaves soon after, and his tracking skills seem to be very... convenient. He is immune to arrows, gunshots and flares, which ordinary bears are not. Of course you could explain this as gameplay, but even Jeremiah says it in the story: the Old Bear is bullet-proof. Just like the demon bear of the Spence legend. Only thing that brings him down is the legendary bear spear - the same one that brought the original demon bear down. Jeremiah explains that maybe ten inches of cold steel will do what bullets can't, but to be honest that doesn't seem very believable. Bullets are pretty good at killing stuff. Even if Jeremiah says he doesn't believe in supernatural, he still seems to believe in the spear. I find it very possible he does actually believe to the magic of the spear, but doesn't say that to Mackenzie, because that would make him look... well, not very believable.
As conclusion: all of this could be explained without supernatural, but I feel like the narrative strongly encourages you to doubt that. There's just so many elements that feel just a little bit wrong and are so much easier to explain through some sort of supernatural phenomena. This is especially interesting, since everything in the Redux is there very deliberately. Hinterlands had a chance to cut off stuff and really focus on the stuff they think is important, and there's a lot of this weird mysticism going on. This is why I believe many things that could be explained as plot holes - like Metusaleh's quick climb - are very well thought out. They had a chance to fix stuff that wasn't intended - and these are things they didn't change them.
I do think there's a supernatural elements in Long Dark, and that the very core of the story will focus around these fantasy elements. However, it's just my feeling about these things. I'm interested in hearing your theories and speculation about these things.