>>8903859
I'm someone who has "followed" ABDL games for quite a while, which basically means occasionally visiting that foxtalestimes forum, the one thing I really hate are games that don't try to be a fetish game or think about why their audience is even there.
It's usually some shitty combat system where the diaper part is kind of just weirdly stapled on or isn't the spotlight. Usually it's RPG maker slop, but not always.

There is also the thing of diapers being somewhat incompatible with game mechanics. It only makes sense for using diapers to be a fail state, but that's the whole reason you're there. There are many of those slop games I've played where I'm literally going against what's "designed" for something fetishy to happen.

I've always thought the best idea for games are basically visual novels, or something a bit more sandboxy where you're just going around interacting with stuff/people to make stuff happen.

>2D or 3D? Somewhere in between?
As with any indie game, 2D is "easier" but can lead to a shitload of more art work if it's very animation heavy, but a diaper game probably isn't.
>Level of quality
I don't think people have super high quality standards for niche fetish games, at least I don't.
>Story driven, manual scene-driven, or freeform sandbox gameplay?
Seems you already understand my previous point.
>Native exe or in the browser, or even both?
Eh, doesn't matter.
>Assume it would be easily modded
Just make it open source. Don't bother with all of the actual work required to make a real modding system for something like this.