Man, this was an amazing first part. Just too much to write about. Though I will do my best to note the parts I liked and disliked the most.
I really liked how Cecil ends up being contrasted between Iggy in that Cecil is the better friend to Gidget than Iggy is, his selflessness contrasted against Iggy's selfishness...even though he's slowly coming to terms with that. The attention to detail in the writing, like how pre-revelation (as in "before their final confrontation with Cecil") Gidget described instructing the Iggy dolls as "programming" them instead of, say, "commanding" them. The "we're not doing 'lethal vs. non-lethal' choices again, you sadist" joke made me laugh hard :D . I also like how you took the animation lessons you learned from Our Fantastic Wonderland and applied them here - the novel has never looked so animated.
Speaking of which, shame no-one seems to remember the events of Our Fantastic Wonderland. Having Orlam, now surely fully-aware of Wonderland's abilities, take his revenge on Jerry for, just one loop, taking over his self-made role of King of Wonderland would be F U N. In an Orlam kind of way. That and Hunar revealing he and Bucks used to play D&D together would've clicked more with Iggy, being like, "Oh, so that's why one of the loops had Wonderland become a D&D session," and in hindsight, making Our Fantastic Wonderland akin to a standalone Bucks arc.
Speaking of Orlam, darn you, crispy critter! You made me think, at first, Orlam had something to do with Gidget's out-of-character acting being a result of his interference rather than something self-inflicted, what with her (that's what I'm pronoun-ing pre-revelation Gidget so as not to confuse myself) mannerisms, way of speaking, and the choice of music being suspiciously similar to the choices used for Orlam's.
On a minor note, it's a shame there weren't more sound effects in parts. Though I do understand that the (likely) very tight budget regarding third-party asset licensing for the assets you can't get for free likely is a factor there.
Finally, given the intro narration to this arc, I can't help but wonder if there'll be a choice to make at the end: chop down the tree because we humans are inherently flawed, and the poor tree needs to be put out of its misery, or have Bucks surrender the baby to the tree, no blood sacrifice needed, so 1) the baby can be raised by a better parent (sorry, Bucks :( ), and 2) so it can heal and maybe figure out how to live in a world of flawed, guilty, and impure humans?
Looking forward to the conclusion!!!