Honestly, I feel like what Death Stranding is, has been staring us in the face the whole time.
A few more anecdotal observations to support my Silent Hills derivation theory:
1. The first modification Koji-pro's engineers added to Decima was the dynamic fog feature. In hindsight that screams SH to me as it allows real-time transitions between the "normal" and "dark" worlds in open-world setting.
2. Look at the tone of scenes involving the things we know to be called BT's. The entire third trailer showing the void-out has an overt cosmic-horror vibe to it.
3. Bear in mind the main thing that Kojima has been very specifically gunshy about showing are the BT's in their visible form, they have only been shown in Japanese trailers with their appearance being specifically edited out of the last E3 trailer. He's teased us a lot with them being invisible, just leaving oily-looking handprints, but the larger manifestations have been shown very sparingly.
You take away the monsters from Silent Hill, what are you left with? A "walking simulator" by any chance?
I feel like he's been very carefully distancing us from the realization that psychologica horror is a big part of Death Stranding, so we don't catch on, Rather than an abandoned town with scattered survivors to be found, he's just expanded it to being a deserted continent. Rather than sirens announcing the impending arrival of the darkness, we have the timefall, supernatural rain that fast forwards in time everything it touches.
I'm not saying the SF trappings and social metagame aren't important or relevant, just that if you start to distil what we've been shown down to its basic elements, it seems to me to match up surprisingly closely to the Silent Hill experience. We just don't really connect the dots because its been framed in such a way to minimize the spookyness of it all. Despite the fact that its full of pretty tropey stuff, invisible enemies, creepy dolls, spectral figures, "posessed" humans leaking black goo from their orifices...
I'm just saying, if you were to describe what we've seen on paper, it'd come off as pretty damn horrific. Which is crazy really when a lot of people seem stuck on the delivery-guy angle, I mean, hello!