It took me a while to get time to finish reading the visual novel and all the letters and the time to sit down to leave a comment. Unlike everyone else my reason is forgetfulness and the grind of fast food work. It's been so long that, and my memory might be wrong, the game description was even changed. I think when I read it last month the description was something along the lines of "understanding your mother's and your own plurality" which made me download the game instantly and rec it to other friends (Hi sesere!)
My first foray, and what got me interested in reading about mother-daughter relationships, was during this big ice storm that hit my city when I was like 14. My mom downloaded a novel called "The Darkest Child" and she gave it to me to read after she finished it, mainly to go "See how bad other girls get mistreated and yet you complain about me!" There was a period when I was a teen where my mom let me read books about girls being abused by their moms, looking back she was very much trying to get someone to understand her even though it usually came with the caveat of her not trying to understand me. My relationship with my mom was similar to Cori and Rose, enmeshment and groping included. Makes me want to recommend Bernadette to her and see what she thinks, even though I probably won't like what she'll say, also she doesn't read visual novels so its a no go, sadly. Also sad since "The Darkest Child" also had a mother forcing her daughter into sex work so it would have a been interesting circle coming together pick.
Getting to the game proper, I genuinely think the game would be incomplete without your letters. The story with context letters is great, but reading your letters on your creative process, your family, and your system just adds so much that the thought of the game without them feels off. I'm not plural, but right from the start when Rose kicks Cori and a gentler alter immediately fronts, the change in hue from a hard red to a soft pink, the character sprites are faceless but I could vividly picture the expression and change in demeanor as Rose, overcome with regret, tended at her Coco-bear. I like how the text color changes to indicate how Cori and Rose shift; it's subtle, but the personality of each alter and the tone of their voice just links together perfectly. Rose is alive in the game, but reading the game and your letters really made me understand how the game is about grief. Not even grief for the end of a life, the grief that comes with the end of certain possibilities. If Rose and Cori were more financially stable their life could have been different; if anyone had tried to give Rose the care she deserved her life could have been different. It feels poetic that one of the final flashbacks in the game, when Red chokes Rose, mirrors the first scene when Rose kicked Cori. Even though the story focuses mainly on Cori, knowing the conditions that lead to plurality, its not hard to figure out that Rose and Cori mirror each other in more ways than one. It's like how in some of your letters where as an adult, close in age to your mother, you reflect on how your experiences mirror her own. I've had the same thoughts as I've gotten older regarding my own mother.
But Mother, You and I Are Not Bernadette Mayer is also about love, as cliche as talking about grief and love are, but they are a pair that come up together a lot. Love isn't uncomplicated, especially love between mothers and daughters, but it's still here. It may not be able to reach the person it's meant for, but the fact its there for them is enough.