Belle
So first off, thank you for the game, it is awesome. This is my first post on these forums after playing 5-6 different renpy adult games.
Pros:
Your story is awesome. The flexibility in choices/relationships is awesome. The puzzles/investigation mechanic is awesome. The realistic looking and acting characters are awesome. Belle is awesome. Lack of meaningless grind is awesome. The ability to not play the endgame until you want to is awesome.(I hope that isnt temporary)
Cons:
Character animations are basic to non existent. Easy to get lost, side-tracked, and forget what you need to do. Background animation usage is basic to non existent. Lack of variety in NPCs, mostly physical, but plenty of leeway for personalities too.
Things I see you need, purpose is to appeal to the widest audience as possible... The purpose for that is so you get as much recognition as possible, for all the hours and work you have done. I cant see that any of my suggestions will take away from the game, but could add many hours of work for you depending on how the infrastructure was built. I am not a coder, or game developer, my opinion is strictly from the perspective of a gamer, who loves games. I am only going through the trouble of writing this because you went through the trouble of making it. I do not mean to dissuade anyone from playing, it is a great game.
Suggestions:
Using background animations to make the world seem more alive and 3d seems easy, and it might be lite on resources. Essentially make your background the same, just zoom in the camera a little and move it around the background as the scene develops. I think I saw this technique used a few times in your game for small things, like zooming in on things.
A hints mechanic would be wonderful. However you implement it, it should be multiple clicks to get to it, so it isnt easy to use all the time. Maybe have it character based, instead of quest or event based, so the hints can be more vague eg "Have you seen Callie lately?" instead of: "Look for letters on her table while she is gone to change clothes." The point is, us who like puzzles, dont like easy answers... but when we get stumped, we like even less reading through all the spoilers a guide/walkthrough provides. At the same time, not everyone enjoys puzzles, so adding this mechanic will allow them to still enjoy your game. If you really want to get complicated, you could have Belle give out hints based on the time since an objective tree has been touched... but that would be really cool. eg "Are you EVER going to get around to asking Primrose about her lie in the writing room?"
Your foreground animations leave too much imo to the imagination of the player. Moving a body, or worse the camera, back in forth a few times to represent sex is only slightly better than looking at an unmoving picture. I am not sure if you are allowed to borrow ideas from other games, but 'A House in the Rift' does these animations really well. Maybe you dont need it that good, but you can probably get some low cost and fast to implement ideas from it. The animations in that game are probably so good because they use really crappy/simple models.
Variety in physical features... I am not one, but some players enjoy unrealistic breast sizes. Others prefer the thicker ladies. This is an adult games, and players have expectations for their fantasy woman. Nell checks both the asian and petite boxes. Primrose is also petite, but less so than Nell. Callie checks the redhead box, but could easily be modified to check the huge breast one as well. It is an easy adjustment that could appeal to a wider audience.
Closing remarks,
You have a good game, but it could be great depending on how many hours you want to spend. It is all about cost analisys and time management. You can never make everyone happy, so dont try too or you will risk not making anyone happy. Most importantly, you need to be happy. Maybe the game now is a first draft, with polish to come later. If that is the case, I recommend taking a little more time and adding some polish before sharing it to the masses, as first impressions are very difficult to overcome. Thank you for sharing your time and money with us. I hope my remarks have at least been a tiny bit helpful.