17MOONKEYS I'm a fan of UFO, great game with a big focus on milfs that delivers well. This game is in the early stages indeed but I don't see how it will expand too much in any meaningfull direction.
1. No sci-fi / magic / too paranormal or similar
2. Set in a basic house in bumfuck nowhere
3. Focus on mostly one milf character that doesn't look bad, but shes not unique either (there are at least 3-4 games with almost the same head, the only thing thats great is the body, which is great but its the same body as most milfs in your games)
None of these things are particularly bad but taken together they limit where the game's plot and thus scenes can really go. The horror genre as it was already said here isn't gonna be too popular by itself, you should design a hentai game around its scenes and bigger plot milestones, the setting is just there to help with that.
There are a lot of sh0ta 1ncest games out there, most of the popular ones are popular not despite but because they have all of the same usual characters, the mom, older/younger sis, hot aunt, cousins, milf neighbour, teacher etc. You don't need to make too generic of a game but I think you should reevaluate the setting of this one and where you want the story to go, especially in its current state where we're probably not gonna see many characters overall and new ones anytime soon.
If you already want it to be horror/paranormal then either:
1. Make a full horror game focusing on horror very obviously and add paranormal mommies (check out Infinity Realm, simple but the content is good)
2. Mix something similar into the already existing setup here, for example the MC wakes up the spirit inside that doll on the attic, she later on brings him into some underground paranormal coraline like new world and then you have 2 parts to the game, the normal above where later on the MCs family can move in or some neighbours somehow and the crazy world below with different events that would mix the two together depending on what you want exactly etc.
This would add uniqueness to the game with its horror elements and demon mommy type of models while also allowing you to easily add those characters whenever you want into the plot to spice up the updates and keep intrest in your game.
Personaly, I also would like to say that you should never switch your games to be sandbox, and in regards to all of your current and future games I would also suggest adding more:
1. Breastfeeding scenes
2. Choco mommies
3. MC cucking husbands
Good luck.