Sorry, I'm late. But at least that means one more voter.
I must say, you all did amazing with a very, very difficult topic and by far exceeded my expectations. I asked for two choices for the reader as a minimum, but I also thought you all would not go much about this. You did and the quality of your entries is astonishing.
I read the stories a couple days ago when I checked for correct links and haven't re-read any of them, so my feedback will not be as detailed as I would like it to be.
cat: You chose a fairly mundane scene to illustrate how the small choices we make can alter our experiences but my ultimately all lead to the same destination (quite literally as train stops). I really liked the small detail of naiming all the links after - I think - subway stations in London. Unfortunately, the excitement of reading through this adventure is missing. The situation is too normal to create anything like suspense. As a reader, you wait for something to happen - and it just doesn't. That's obviously not what you were going for, but I think a reader expects it in a Choose-Your-Own-Adventure type story.
Frodo: I like the idea of setting the story in two different times. I accidentally read part of a present paragraph after only seeing the part set in the past before and was througholy confused how I would get from one part to the other. You found a convincing way. I'm sad that the curse Anastasia might or might not unleash never really came back after the first part. In the present I was very confused by the dynamic of the characters. We learn that Ana keeps to herself and isn't good with people and still Gunthar seems to know her and acts around her as if they were friends. Even worse, in my first playthrough, I sent Ben away to the library in the first meeting but the later paths of the story do not account for that. Ana and Ben later react to each other as if they spent the afteroon together no matter what. Gunther and Ben also seem to know each other and I have no idea how, because Ben is new to the city.

I also wondered why you put the decisions where you did and then had the same text for a few lines in both choices. In a published book, I'd call this padding.
WHAM: Holy... You did not write one story with different paths, you wrote about thirty different ones. And you hardly ever recycled a paragraph. One of the few (the only one? I can't remember.) I encountered more than once is the one where the protagonist gets poisened after a night in the tavern. The first time I came to this end, it made sense: I had just joked about the nobility and pissed them off. Other times, this ending made a little less sense, for example after I told a story about love or hate (I think - as I said, I haven't re-read and you have a lot of content to remember). I love how diverse the paths are and how evocative your language is. You have a bit of gender confusion here and there, refering to someone as he and than later her. I really loved your ending 51, I'm glad I found the secret path.
Baron: Your story felt the most like an adventure and the most like I could base my decisions on facts provided to me by the stroy beforehand. To a degree, that is true and at the same time it often was not. The very first decision (within walls or beyond walls) has very little clues, if any, and determines the whole outcome of the story. Unless I mis-remember, there is absolutely no way to get a good ending
within walls. Actually, good endings are very hard to come by in your story. I think I saved Katarina once and managed to live somewhat happily with her in the dream world once? That's not a lot. I'm a bit disappointed that there was no way to find more information about Enrico. He's mentioned in both general paths in the very beginning but then not again, like a plot threat that was just forgotten. I like the structure of the dream sequences for a Choose-Your-Own-Adventure story. The fact that each sequence is more or less self-contained makes it managable for both the writer and the reader.
Now, my votes:
Best Character: FrodoBest Atmosphere: WHAM, without a doubt. Not least because it were so many different scenes and feelings the story created.
Best Writing:WHAM, so many scenes, so many pictures in my head.
Best Branching Plot: I was torn here, WHAM's work is amazing, but I come to the conclusion that it is not one story with a branching plot but about thirty different ones that happen to share a beginning. So I go with
Baron here, as the story that best shows how one plot can branch out and find its way to conclusions that are all obviously set in the same story.
And that leaves us with the following results:
WHAM wins the golden diagrem of branches with 6 votes. I tried to draw your structure (not really) but I gave up.
Baron recieves 5 votes for a very good second place.

And
Frodo manages to score 3 points for a bronze statue.
Congratulations to all of you for dealing with this topic as well as you did.
Over to you, WHAM! See you next round.