If what you want is a real Role-playing game, I don't know of any that truly qualify. However, there are a few that use RPG elements to drive the story.
The Artifact and
Incest Adventure are both made by the same developer in RPGM and both make use of the engine to add combat sequences to their story. IA actually does have a leveling mechanism, and I am fairly certain that it isn't scaled, so if you didn't earn enough experience fighting you would lose to some of the boss characters. TA doesn't use the same method and actually works more like an action rpg, where you gain skills and fight better in that sense. They have acceptable Incest Harem plots. I wouldn't call them bad, but I also wouldn't put them in a top 20.
As for Dating-Sims... we have kinda strayed from the typical DS model of buying gifts and grinding personal stats to interact in favor of a more streamlined "Life Sim" experience. Life Sims are games like Big Brother or Man of the House. As for good Life Sims I'd point you to
Milfy City (still in its 0.1) This game manages to be a life sim without needless grind. You advance the plot through story rather than the typical one sided affair that is normally associated with this genre. I would also point you to
View of Family. This game isn't quite as well written as Milfy City,
however before MC came out I was putting it up as the contrast to how bad Big Brother and Man of the House are. It does have some grind, however its never so much that you're not interested in continuing. I'd also recommend
Chloe18. This is a Life sim that combines corruption and coming of age to a female protagonist game to allow you, as the titular Chloe to transform from mousy good student into a fun loving slut.
I have nothing for you in the post apocolyptic category that I think is good, unless you want to count
Family Values which takes place after WWIII in a world where a bioweapon killed 99.99 percent of men and the war killed 95 percent of women. Its a fun little incest game.
Other games I would count as great,
Coceter Chronicles In this game you play as Tabitha, a Tainted (half demon half fae) servant to the princess. You are chosen because of the fact that you're the only Tainted who can read in the entire kingdom (because it's not allowed for tainted to be taught to read) and you are therefore the most expendable person who can reliably carry out the mission, to go to the human realm. In this game there is something sexual to do around every corner. It is a must play if you enjoy fantasy at all.
Depraved Awakening This game is a noir detective story in which you work to solve the case of who killed your client. The investigation leads you through the widow to this depraved sex club that seems to be responsible for everything. I don't want to say too much, as it would be spoilers, but this game is amazing.
Wicked Choices This is another fantasy, but this time it's a VN. The author behind this gem is an actual Erotica writer and this game is so fun. The game opens on the main character, after a summer of temptation with his niece, as he finally comes to the choice of whether or not they'll move forward. It is quite the opener, however just as you finish you we are transported to another place, where we see that what appears to be an elf princess just empathetically and telepathically experienced the sex you just had with your niece. The story only gets more interesting from here.
Babysitter This game is really good. I cannot recommend it enough. The writer who came on during the last few updates is amazing. He is who I go to to ask for assistance with my own writing for my games. He is who I bounce ideas off of. He's that great. In this game though, you play a software designer and single uncle to your niece Christine who's come to stay with you as she looks to begin her adult life and become a journalist. What happens from there in a branching adventure is up to you. It is great fun with properly fleshed out villains and hot women.
Parental Love This game does right everything that the popular Dating my Daughter does wrong. Similar Premise, you, the father, were estranged from your daughter for actually 16 years in this story... oh... did I say daughter? I meant daughters. And your hot wife. You come back into their lives after dealing with a drug addiction and putting your life back together. Lucky you, the girls have daddy issues and they're hot as hell, but Mom also misses her husband. Its a wild ride as you come home and begin a new life with them.
My Sweet Neighbor This is the same mechanically as the last two games, however without, as yet, any incest. You play a guy who starts dating his neighbor while he and said neighbors daughter also have a blooming romance. Honestly, the setup for this game is a little complicated to type out, without just telling you exactly how the game does it, so I'll let you play the first bit for yourself and decide.
These games are all great so I hope you'll try them all. If you need more and no one else has what you want, I can offer more, but my notifications are piling up, let me know.
@TCMS if you could move this.
