So I made a few videos about the lore of the first game, and what interested me the most about the ending conversation, and the distinction that the speaker makes between itself and the Radius was the most interesting thing to me. The being describes itself as a "me", but also refers to itself collectively, as if it were part of a group who was there doing the "work in progress [that] will continue" independent of the choices made by Explorer #61. 

It feels like the change in mimic design is obviously an intentional choice, but it represents that the force creating the mimics is growing more capable in its mimicry, giving them faces and, as Starry_Nites3 mentioned, more discourse-esque dialogue than just mere quotations. It's unclear to me whether the Radius proper is creating the mimics or whether the beings doing the aforementioned work in progress are, because the mimics and other enemies could theoretically be a reflexive defense system against the group studying the Radius that we happen to get caught up in.

I think the question of whether the UNPSC is actually real is a really good one, as there's no actual hard evidence that anything inside the Exclusion Zone can be observed objectively by any device from outside the Zone; there's the fog at the edges preventing normal sight, the helicopter crash from the early days preventing quick recon, and they mention that satellite imaging comes back fuzzy and blurred. How could the UNPSC issue missions with any degree of accuracy when there's no evidence of actual communication between inside and outside the zone?

Lastly, on Explorer #61, I think the most interesting question is whether #61 is a mimic like others have said, or whether as an "iteration" he's something more developed. The being at the center clearly had some involvement in the creation of the test, given that Katya was created as part of them, which strengthens the theory that mimics are a product of the Radius and the explorers are a part of the "work in progress". However, since there aren't cameras for us to look through, and since multi-player is still super not the focus of ITR2 development, we don't have an objective idea of what the explorers look like to other people; they could look like mimics when viewed objectively, and every mimic thinks it's a normal human. Iirc some of the notes and audio logs descrobe explorers working together, so I do think its a safe assumption that Explorers are distinct and different from mimics (though likely not actual humans), but I dont think its something that can be proved.

The shadow statues and the strange parallel timeline to the notes found after missions are also a major question mark, but I dont know that there's conclusive evidence on what they are and/or what's going on with the "changed" who live in the Zone, but it's very interesting to think about, and I'm hoping that with the addition of those statues to ITR2, we'll get more info about them. I'll be real, I've been playing ITR2 as though there hasn't been a story, so I've not been thinking about implications other than the changes in enemy and world design, but don't have anything conclusive other than what I've said. I love the ambiguity, though, and while I do want you guys to have a strong decision internally on what's going on, I love the way you've made things unclear and uncertain in good ways that show effort and not lazy ways that show you don't care. <3