loads of the ‘lore’ is currently in the laboratory computers.
The opening could possibly use a mention of the Eastern/Western Bloc tensions, but aside from that the storytelling is probably best in taking the Dark Souls route in which the picture is hazy, fragmented and delivered slowly over the course of one’s explorations.
Hell, I actually oppose requiring in-depth, explicit reasoning and description as to how every creature works, where it came from, what it wants, ect, ect… because at a certain point one is going to need to accept that even the researchers either had no clue because it was just too damn bizzare, nobody has seen it before, or they couldn’t spare the time to write it all down in between panicked running and reloading.