So I've been playing some other fetish games, and a few things are clear, 1 there is too much rpg maker, and way too many of them are being used as rpgs,
grinding isn't fun, don't make me grind for the release. there's also a lote of visual novels and I think that's for a similar reason as to the rpg maker games, it's acessable, you don't really need to learn how to code to make one, you just need some good assets.
What I think is the crux of what is fun for most of these games, including abdl is picture getting progressively more fetish, this works in multipule differnt facits, I've sene a clicker game where every think you upgrade goes though five pictures of them losing material,
I've seen an rpg maker game where there were various pictures of someone being more and more pregnant, and a visual novel game where people get more and more bimbo,
none of them would be fun as games themselves, but that picture changing thing that's the shit,
I also tried a framing game where they suggested some transformations, though mostly it stayed the same, and that kept me going more than I thought possible
So really it's just, picture sequences as rewards, is your meta loop for sccess, just need to make a game that's fun to play to tack onto it.