Visual novels aren't the type of game I usually play so I don't think I can give much feedback on how well this compares to others in its genre, but I do think the setting of Hong Kong in the 50's(?) is pretty neat.I played through a chunk and listed some bugs and other things I noticed below.
1. I had some issues with the settings menu as well as backgrounds/pictures loading in the first time I started the game up, but those issues didn't crop up when I continued my saved game starting the game up for a second time (Not sure what happened there.)
2. When I started my saved my game the dialogue mode was in 'auto' but 'auto' was not highlighted in red. I had to click 'auto' to put the text advancement back in manual mode.
3. I didn't initially realize you could scroll the map with W & S. Might be something to add an indicator for in the future.
4. I noticed that the SFX for hovering over buttons has a slight delay to it. Feels odd to me when moving my cursor over stuff and then the SFX comes in slightly after it.
5. There was an instance in the narrative where Hazel is said to feel like she was just something to be bargained for or owned by her husband, Leonard. It's a pretty direct statement about her feelings early on where we don't know much about Leonard and I feel like the story could benefit from maybe implying this through character interaction as opposed to directly telling the player through the second person narration. (More showing and less telling.)
The UI for the game is well-done and everything is pretty readable and easy to navigate. I think the color palette for the game in general does well at setting the mood. The background art is quite painterly and eerie and the map of Hong Kong does a good job of cutting the explorable areas up into chunk while drawing your eye to the various quest markers.
I'm also just realizing as I'm writing this that Undying is an otome game. The vibes I got from playing it now make sense lol. Looks like you've made a lot of them.