I'm so glad I reread it in one go; reading it the first time, there were so many things that bothered me, things I thought would never make sense, or were poorly characterized, but now, I've seen the light. :)
To write a story this complex and so multi-layered took a great deal of planning, research and imagination. I'm in awe, really. I do love a story that's so rich in description (although I know we haggled a bit about this--from me, that's the pot calling the kettle black!); you created a world where all of my senses were engaged, and I'm so glad you stuck to your instincts on that point. Description to this extent is not every reader's cup of tea, but it is mine, and certainly is yours as well.
What I admire most, though, it that you had to characterize two separate Snapes, present them both from the beginning, and yet somehow manage to not clue the reader in that that were different. As a writer, I can appreciate how difficult this is, and it's a testament to your skill that I never once suspected until you revealed it in your own time. Of course, we only saw that first Snape through the eyes of others or in Pensieve memories, while we learnt the new one along with Harry.
There were so many times in this that I was frustrated beyond belief; I railed against Snape's stupidity and lack of integrity in honoring his prior character and choices, but it all came together in the end; it was because of the second Snape's integrity that he reacted/acted the way he did.
So many other things I want to mention: the original magic, Endell's story, your original characters, the inclusion of canon characters (also deeply characterized), the detail of the runic garden, the portraits, Kreacher, and the sexual scenes that acted out their relationship on a more subliminal level--all of it done so well, Kayla.
I know the length was a concern, but I'm so very glad you let your heart and mind take you where you needed to go, because it's a great story, a compelling one, the proof of which is that I've thought of it for months, ever since the first time I read it.
Doesn't matter to me what team you're on, kid. You did a wonderful job; you should be proud, and ex-Capitan or not, I sure as hell am. Congrats!