Describe this topic in more detail, if you want me to personally in the Discord, with pictures and examples, it sounds cool, the game is still being tested, for me it's all new)
Well, let me go by parts: I saw the screenshots of this game and thought "it looks a lot like a Doom wad", which by the way is not a bad thing, I love oldschool Doom/Heretic/Hexen/Strife (they're all built in the same game engine and have similar mechanics).
So that also made me remember that back when I discovered CoC and TiTS, years ago, I thought "this game would be cool in a 3D style", because both CoC and TiTS have similar mechanics, and a lot of porn.
Then around that time, I discovered HDoom, which is kinda a cool concept, but it's clunky and heavily dependant of sprite animations, which the Doom engine is not very friendly with. But, ZDoom/GZDoom made a world of things possible.
So Doom WADs (mods basically) allow the game to be completely converted to pretty much anything anyone wants, but retain the 3D space the Doom engine used. Strife, for example, was the first game to try to make a RPG in the Doom engine, with dialog boxes, inventory management and vendors etc... and it was quite cool for the time. For today, meh, it's quite simple, but has it's charm still. While Heretic and Hexen have some light-RPG mechanics, but are pretty much DnD themed fps shooters (but with the map/hub areas complexity of a RPG game, where you have to solve puzzles to progress in maps.
My idea was to make the gameplay mechanics of CoC/TiTS (char customization, sex interactions in text dialog boxes, and a really basic RPG stat system) into the GZDoom engine, so we would have the player navigating the world spaces in 3D, and fighting enemies like in Doom engine games, but interact with them via text prompts when needed, like talking with NPCs or activating a sex scene, which is kinda how Strife also give quests/missions and such.
Now, why do it in the Doom engine instead of Unity or whatever else? First because it is ALL free (well except for base doom game, but c'mon, Romero and Carmack don't give a fuck anymore if people copy some floppy disks around after all these decades) and supported with great simple tools for making the maps and scripts (the map editor for example is literally just drawing lines and selecting textures and seeing it all being done in real-time in 3D, it can be lots more complex of course, but can be that simple also). Second because it's all very well documented, and quite easy to learn, I myself did a few mods using ZScript and ACS, but don't really have the willpower to do anything actually impressive in scope. And third because, as I said before, something with the 3D freedom of Doom but the mechanics of the porn games could be really fun, not only to actually play and enjoy, but also in the erotic/fap side of things if done right.
So, to have references I would say check out HDoom for the actual sprite porn side of things (that would be pretty much he style of any graphic porn the game would have), Strife for the equipement/interactions/quest style, and Doom/Heretic/Hexen themselves would be the rest of the gameplay (combat, defeating some specific enemies then maybe lead to sex interactions like in CoC/TiTS, etc...)
But that's it, just a dumb idea, I don't have anything concrete apart from the games I spoke. It's not that it all would be a LOT easier to do than any other engine, it would be just a little bit easier if one would go implement all those mechanics in the doom engine rather than making from scratch in any other engine.