Could you describe them a bit more?
The Spinney (Renpy): After a pandemic you're in an isolated area with an asian girl. You meet more girls during the game (Don't remember how many, 7 ? 8 ?) You provide them protection and a place to live. So it also has a light management part.
You can fuck each girl and have a special relation with each one (The submissive one, the girlfriend one, the brat... etc).
The pandemic also affected them to push their Lust and open their mind. There is a corruption part but it's not fully in the game yet, so I have no idea where the dev wants to push his game.
I think the MC is going more dominant at each release/step of the game, but it's my point of view, I don't know if the dev does it on purpose.
I also re-read the thread, he didn't answer the question about pregnancy. No idea if it will be a feature (ask him maybe?) but it seems difficult in a real porn game.
The game is still in development, no idea if the harem will stay full at the end. There is no other male in the game, so it should stay like this.
Fairytale (HTML): It's in "real life", in a city, but you meet a fairy with magical powers. You can influence the girls too, to conquer all of them. The main plot is quite good (You face opponent like a witch for example, and you have to make them submit to you too to expand your influence in the city.).
There are more girls than in the Spinney (No idea how many, but around 20-25 I would say.) However, each girl has more linear story, with less background than the Spinney.
The game is still in development, no idea if the harem will stay full at the end. There is no other male in the game, so it should stay like this, except if the magic part of the game pushes the story in another way.
Both are sandbox.
My opinion:
Fairytale is a really good game but it could be repetitive (find a new girl, corrupt her and add her to your harem.) The story of each girl is not pushed really deep. You have a lot of different models.
The Spinney is the best real porn game I saw on this site. It's a bit slow at the start, but it gives you time to understand the management part of the game too.
You don't have a huge number of girls in your harem, but each girl is coming with a real story and a real personality. It's pretty rare for real porn games, usually dev are just putting lots of scenes without carrying about the story. When you meet a new girl, you slowly corrupt her and grab her in your harem. Usually in real porn games, after a few talks, you already fuck the girl.