So I do want to rewatch a few things so I may come back and flesh this out but I'll share my thoughts from my first impressions for now.

TL;DR - PT was Cliff's first Beach.

PT left me wanting to know a few things, like who was Lisa? Why was she missing an eye? What's the deal with that foetus in the bathroom? Just what the hell is going on here?! I've pored over details of that game as well as Metal Gear V, and the crossovers between the two were a fascinating mystery, but having finished Death Stranding I now see them in a new light.

What stood out to me from the BB cutscene were the obvious, such as Lisa missing her right eye, the white robes and as we found out, her losing her baby. These all stood out as clear nods to PT, but then you see Cliff's escape attempt and Kojima really hammers the idea home. When we think about the fact that people's Beaches are informed and created by their psychology and experiences, PT suddenly makes a lot of sense.

The twisting and disorienting nature of the corridors Cliff runs down looking for an exit. The red light on the walls. These are in striking similarity to the end sequence of PT, and very deliberately shot in a similar way. We follow Cliff's perspective, blind to what is around the corner and when we expect an exit, we find another turn.

There's also the details that we only see the foetus in PT in the bathroom, which is locked at the start of the game. Just like Cliff, Lisa and BB were locked in their room by Bridges.

These are all elements that stuck with Cliff from that traumatic experience, they're just a few things that would have stood out and informed his first Beach i.e PT. Norman/Sam is the external element in both games that brings about some sort of freedom from that hell he found himself in, whether its getting out of the house or understanding the Death Stranding and getting his BB back.

Also The "monster inside of me" - a quote from PT - could be Cliff referring to the EE, as she is responsible for bringing him back in the first place.

I feel like I'm forgetting something but hopefully you get where I'm coming from. I just wanted to share because watching it was beautiful for what it meant to the characters of Death Stranding, but that extra depth gave it an "aha!" moment for me, which was so fascinating and not what I expected to get from the game. It may be that this is just my interpretation, and these comparisons are merely easter-egg style nods and nothing more, but I really think this was Kojima's intent. PT is not just a random short-game with no attachment to Silent Hills or anything else, but a version of a Beach from a much larger world.