Spoilers for The Heart of the World ahead! You've been warned
I just finished reading your book! I definitely enjoyed it but I'm not sure if my opinion is influenced by the original fic. Ilyn was probably my favorite character besides Frank, I can kind of see what characters you referenced for who but I think you did a really good job with him, the whole thing he has going on with 'Lily's mother' is especially intriguing because it's not something that happened in the fic.
I'll hussle my book nerd friend into reading it when she's back in town so I can see what someone with a fresh pair of eyes thinks.
That being said I do kind of miss some of the plot points you cut (like the whole Therapy plot and terrorizing her adoptive family) but I can see why you'd cut that for the sake of the pacing. Honestly I never realized how long the original fic was but I blew through the book in the three days I've had it. I definitely want to see how it goes from here, what things will remain the same and how far from the original plot we'll deviate.
Lily herself is... Lily, I've always liked the way she's written. I feel like she's more humanized in this story, or at least a bit more sympathetic to others. I'm not sure if that's what you intended or if she just comes across as a bit more normal because we didn't get that long introduction that establishes her as a borderline lunatic (can't think of a more accurate word rn) She's still otherworldly, but maybe a bit more grounded in this story? Then again it's been a few years since I last read the fic so my memories might be exaggerating some things.
I think my favourite moment was when Lenin said "that's not me" when Lily met the younger version of him but I think that the fact that I can predict or remember certain plot twists spoiled the story for me. I still liked it, I'll be buying the next one and I think I'll enjoy it too but I kind of wish I could erase my memories of the fic, just so I can experience the book the way it's meant to be read as an original story. This way, I'm just drawing comparisons between the two and not looking at it as a standalone story but I can't really help it.
Overall I think you did a really good job with this, at certain parts of the plot (like when Lily first enters the magical world, or when rabbit is introduced) I wished there was more time spent discussing the world or what's happening but I'm assuming you had to condense a lot of it. For the most part I don't think it affects the overall experience of the story too much, except for Rabbit. If the years between Lily being 5-12 weren't cut I think it could have been established better what exactly Rabbit is, or I guess his role as a cosmic horror. From eating the bridge club to eating two tasks is a very large jump and I kind of missed that buildup, and the horror of people and things that were important to the story disappearing gradually. It's entirely possible that I'm getting ahead of myself though and this is all the stuff that will happen later on in the next books, or you simply intended to take a different route this time.
I'm kind of rambling and this ask is getting longer and longer, Anyway, good book, I'll be recommending and lending it to my friends to see what they think since they didn't read the fic. Sorry if I came off as if I was complaining at any point, I really did enjoy reading it
The Heart of the World by me (@janedoewrites)
Glad you enjoyed it overall!
There are things I miss from the original as well, but they didn't fit a) the pacing b) the new world or c) the story in general.
As an example, Lily is definitely more humanized in the book, and part of this is to be a bit more sympathetic but a lot of it has to do with the lack of growing up with the Dursleys who are over the top abusive. The Tylors, in the book, are simply indifferent and absent--and that has a bit of a different effect on Lily as a person compared to the fic.
This also resulted in the lack of the therapy arc as, well, the Tylors aren't even around enough for it to make sense/aren't what Lily saw as thoughtless obtuse abusive obstacles who must be made to do her bidding.
Personally, I think the book is better for it, but the bottom line is that I would say the two are different. There's a lot in common, enough so I took the original down to publish, but I think there's more different than a lot of people realize. It's not just copy/replace with names.
Still very interesting to see people point of the differences, and yes, we're still very much in the beginning here with a lot still to go. So, things not covered in book 1 may be coming up in further books.
But glad you liked it! Interested to hear what your friends think.