I'm glad you enjoyed the art at least but this is pretty rough to hear, honestly. Although, I think authorial intent is usually irrelevant when engaging with media in my opinion, I do want to address some of these criticisms mostly to assess my own skills as a writer and trying to see what went wrong. It seems that the main issue is that... It was sentimental and it felt cheap? Sentiment not Sentimentality? You don't really reference this again so I'm not sure what you mean by this but I'll address everything here...
The first point of Mori feeling detached I do not understand. Being detached from his corpse and showing Memento his past don't seem correlated? Mori had confirmation of eternal happiness which informed his decision to at least help Memento. If anything, he's even more detached from his body because at that point he doesn't really care about the physical world anymore as he, in his mind, believes there's paradise after. It was a choice born of progressing the plot, but I don't see how it's forced or unearned?
And, no, I have never read Discord nor have to made any intentional references to this Neil Gaiman. The framing of a play is more slightly inspired by the performance from Bojack Horseman's View From Halfway Down though it was given a more classical, theatrical aesthetic. As for Memento, I can see how some of his characterization can be inconsistent. Memento understands stuff like a flower or a sunset as bringing people happiness, but Mori describes a more visceral kind of happiness to Memento. Memento's view on it is surface level and it's Mori's lived experience that shows him the deeper nuance to it.
As for Stella, I dont' see where the parallel to Memento comes from, personally. She's intended to show Mori's decaying connections with people and how he pushed people away. She was a dear friend to Mori, showing Memento was sorrow is while alluding to Mori's own past, and also them leaving on the worst of terms with no real resolution making Mori more regretful and truly alone by the end. The rest of that section of the criticism I don't understand? "She's perhaps being given an excessive response but the burden of caring is sorta with the living, not the deceased" I don't know what this means? She's... Caring for Mori? And she said things that might've been inappropriate at the time? That was the intention of that scene, that Stella had good intentions but it's clear she didn't truly understand. So... I don't know what to make of this section?
Also, Memento doesn't necessarily fawn over Mori. He's just naturally affectionate and kind, as he mentions that he allows dog lovers to give him belly rubs. He wants to be approachable and comforting and the exaggerated expressions are part of that. There was no real way to make their romance a typical one, so I was aiming for Memento actually experiencing these emotions for the first time and it being overwhelming as opposed to it being a legitimate romantic relationship. As Mori put it, it was one last performance together, and he simply wanted to be with someone at least. Though, caps lock is a mistake on my part and I'll def refrain from using it in the future. It does not seem to be a popular choice. The chase scene was also one I greatly enjoyed writing, but I never really felt the need to make it more than that. I added a moment of foreshadowing this aspect of Memento in the beginning and I think that was appropriate as this is a shorter form visual novel and I feel having three separate instances of it would've reduced the impact of when Memento fully showcases that aspect of his personality. He IS death and he WILL take Mori and, to me, that scene lasted as long as it needed to. It was intended to be longer, but I don't think we needed more explanation from Mori of him running or Memento telling him it's futile.
Mori wanting a dog was more so just a little thing that connected to his loneliness and the desire for someone close to him. And Memento selecting Mori is outright said as just a 'random thing'. Memento says he could've chosen the last one or the last one but he decided this one for no other real reason. Sometimes, we just decide it's time to do something. Memento says reapers evolve over time and it came to the point where Memento had acquired enough human experience to begin questioning things. Mori just so happened to be the person he asked first. I don't think there really needs to be a deeper meaning to his selection. This is Memento's first time actually engaging and trying to understand a person for an elongated period of time. He has seen endless people, but this time he's witnessing it for himself and it's what pushes him over the edge. He's actually feeling a growing human connection for the first time in millions of years.
I hope I did not come across as rude here, but I've seen a lot of criticism that I don't understand or are answered in the text and it's been somewhat frustrating. Maybe I could have made my points more overt but I worry about making things unsubtle which Purkka mentioned was an issue that it wasn't subtle so... I don't know. I do have a thin skin when it comes to criticism so I guess I just need to toughen up in that regard, but I did want to say SOMETHING at least because some of these criticisms I find hard to understand. Caps lock being bad? Yeah I get that. Maybe I could've made Memento's familiarity a bit more consistent? Maybe showed he does understand some of it, but only at a surface level. But stuff like Memento selecting Mori feeling forced or Stella being a foil to Memento I just... Don't understand. It's disappointing to hear that the sentiment of the story felt unearned. Things being unearned and forced seem like the hallmark of amateur writing so I'm pretty ashamed of myself that it came across that way. I guess I'll just have to do better in the future but thanks for reading and I'm glad you at least enjoyed parts of it.