Here's what I've been working on for months: a detailed summary of my theories on the series mystery and solutions to the first four games. Despite there being a few bits that I find a bit unlikely, I feel like I've solved this - actually solved it - like nothing that I've seen anywhere else online. (Or I'm horribly wrong. I dunno.)
I have to warn you that this is long, incredibly long. Although EP1-EP4 are covered in this post, there are spoilers for EP5 based on a single playthrough. No knowledge of EP6 has affected this post.