Context: years ago, the MC's father was killed in the service of the king, and she received a form "thank you for your sacrifice" letter. Years later, she now meets the king in person.
King: Have we met before?
MC: We corresponded briefly.
Plot twist: Vashti *is* the antagonist. She's a Daenerys-like character, seeming like a protagonist at first, seeking initially to reclaim her legacy, and later to 'fix' everything that's wrong with the kingdom and the world, but in the end, becomes the evil that she was fighting.
It varies. At some points, the reader is expected to feel "ok this is done and we're not coming back to it" and at others "I wonder if we ever come back to it"
There are going to be questionaires at certain checkpoints. This is of course not a fass/fail test for the reader, but info-gathering for me - was it understandable that X and Y are connected, did Z affect the reader they way I expected it to, etc.
First, I want to know the multiple storylines coexist in harmony and their combination is enjoyable, rather than confusing. Because if that doesn't work, then nothing else matter.
Second, character arcs and emotional continuity and making sure the major emotional beats land as intended.
"The man’s almost-corpse dropped with the heaviness of a boulder"
Perhaps try "The half-dead man dropped, heavy as a boulder"? Neither "almost-corpse" nor "with the heaviness of..." sound natural.
"surrounding him, like a necklace on a girls neck. Still, they did not dare approach"
This...