Ideas, you say? Well, the first one that come so my head is a local dating sim. You are in a bathhouse filled with boys (and men) of all sorts and your goal is to talk them into fuck. But the Itch.io is already full of dating simulators and visual novels. So my second thought is a Dungeon Crawler. Something like Soul Knight if you know what is it. You have a rooms with enemies where you being locked down until you defeat them all, rooms with loot, rooms with NPC, rooms with random events, ect. And a boss room of course. But I'm not sure what kind of plot can be made for a bathhouse to make it a Dungeon Crawler. On the other hand a DC in a bathhouse sounds comical and maybe you don't need plot at all. Just go shoot/kick/punch the bad guys (whoever they are) and fuck with the good guys.