1) A dev who has ever made a game before. I don't even necessarily mean a good game. I just mean that they've made something, from start to finish, and actually have a sense of how to get things done. This should also mean that they have at least an outline of what they want the game's story to be, a sense of the core gameplay loop they're putting in, and hopefully at least some writing done before they even begin coding the thing. I've seen so many posts from so many people who wanted to get some Patreon money asking how you get started making a game, and that's the wrong fucking way to get this going. Make a complete free game, make mistakes, learn from those mistakes, and only then should you consider getting paid to make a game.
2) Tags. For me, a great game has blood-related heterosexual incest. It's not impossible to make a great game without that, but that's what I'm looking for. No steps, no adopteds, no landladies, etc. And if possible, I would like the development of that relationship to actually tie in some way into the game's story. See: Summertime Saga and Man of the House for this. I wish The Company would do this with the main character's family, but in spite of how much time you spend with them it always seems like a side story, and that kinda bothers me.
Other than that: big-ass tiddies (not the weird plasic ones like in Fasder's "Life," if possible, but preferably with a bit of sag like in SS or Man of the House), and mind control and impregnation are icing on the cake but not precisely essential. No gay stuff, no sex changes, no furries. Not my scene. And yes, a game primarily featuring stuff that's clearly not my scene changes its level of 'greatness' for me. Can't please everybody. Also, I tend to find that games that try to do everything end up shortchanging everybody, because there's only so much development time to go around. Focus on your main audience and make them happy.
3) What do I see: text and/or images. First off, I have enjoyed text-only porn games in the past and, were people to make more of them along the lines I enjoy, I likely would still enjoy them. See Seztworks' games, for example, since technically the text-based part is good enough for me but it also has images which makes things even better. But this requires proper spelling and grammar, good editing skills, and just in general a flare for writing. If you think, for example, that every noun or important word is supposed to be capitalized, text-only isn't for you.
As far as images go, make them unique. Never ever use Honey Select, because Honey Select games all look the same and also all look like dogshit. If you use Daz3d stuff, make the models your own. Change proportions, use non-standard outfits, etc. Or use real life porn star images! Those are great. See The Company for good usage of those.
4) Gameplay: have some! Nothing makes me regret a game download more than seeing that it's all just a big dialogue tree. As long as the gameplay isn't a huge hassle timesink (see: the money- and intelligence-making memory-based minigames in Astaros3D's "My Cute Roommate"; or NLT's incredibly tedious item fetching nonsense in Lust Epidemic) but is actually something the player might enjoy doing or at least has good rewards (LoQO's combat is actually kinda fun, and Summertime Saga's minigames might be a bit of a hassle but they're generally quick compared to what you get out of them), I think these add to the game.
I realize that some people are in love with visual novels and all they want when they sit down to play a porn game is to read a sexy story with some pictures, but I'm not that person. If I want to play a porn game, I want there to be game there.
5) Narrative: this, done well, is essential. To clarify the difference among plot, story, and narrative, see the following from dailywritingtips: "Narrative is the structure of events — the architecture of the story, comparable to the design of a building. Story is the sequence of events, the order in which the narrative occurs — the tour through the building. Plot is the sum of the events, told not necessarily in sequential order, but generally consistent with the story and often considered synonymous with the narrative — the building itself."
All that is to say: I don't give a shit if crazy stuff happens in your plot, and I don't care too much if it's ordered well. I care that the fundamental structure of your game is strong and compelling. I want the game to have a consistent voice, consistent style, and to understand when stuff has changed. If the protagonist got his mom pregnant, I want her to feel some way about it. If the protagonist meets somebody new, I want to have a clear sense of how they relate to one another. If somebody won't bang the protagonist, I want to know why. If something happens in the story, I want the consequences to be clear. Note, however, that I don't think there's anything wrong with clearly presenting a protagonist who's conflicted or bowing to certain porn game cliches. For example: it's fully consistent with the canon of porn games for a protagonist to think they're a totally normal and generally good guy, but also peep on their sister in the shower and try to creampie said sister. I'm fully down with that, think that such a character can be both written well and consistently, and have absolutely no interest in arguing with somebody over whether or not such a character is acceptable in a porn game.
One example of a well-executed narrative: I think Daughter for Dessert's narrative is exceptionally strong, which comes in part from Palmer (the dev) having actually made games before and refined his craft. The characterization is consistent, the relationships are frought and interesting, and everybody has clearly defined reasons for doing what they do. When the game's events unfold, the consequences of those events are clear and sufficiently broadly felt. The pacing is a bit slow as far as the game goes (when comparing length of chapters versus number of sex scenes, especially in the beginning) and not every minigame is the best (bartending in particular is a bit of a dog in I think the second chapter), but there's a reason people like Palmer's work.
Most importantly, though, this is a great game for me, specifically. Other people prioritize different things or think things differently, and that doesn't necessarily mean their ideal game is better or worse than mine, but just different. Like I said in 2, you can't please everybody. And I'd honestly urge a dev with a real vision for what they want to do not to really try to please everybody. That's how you dilute a great work into something that's just okay. Make your game, as best you can.
Final thought: Don't be Disney. Take risks! This is porn, for fuck's sake!
