First of all, gigantic or super-large breast and ass, especially the wide ass of a 200 kg woman in a magically small body.
I just can't understand how people can find that attractive?
If it's some bondage and and the women area treated as cows and are made to have gigantic breasts, that tend to be a quick turn of as example. Another turnoff is when in this scenario, that the women becomes a complete dumb idiots and that's a part of the story plot and other men just stick their dicks in without any story or proper character building.
Sure, if you are at 200 kg yourself, then your choices might be limited in reality, but not when it comes to porn.
It feels like a nerd thing, or the cool thing to talk about. Same goes for that super-large dick which makes women massively expand. It's like a women thing, that women joke around with, but again, porn is different.
What people talk about is rarely their own interest, they tend to just discuss the largest sizes, due to being scared of discussing what they prefer, which is understandable, but it's also good to understand this when making a game.
A large dick or proportions isn't bad, but there's limits.
These so called 3D/"real-life" images, they in 90% of the time, turns me off, due to often being life-less and stale and very limited in amounts.
Some gets it to an acceptable stage, but those are very few.
When it comes to 2D, it could become too much of a cartoon, for it to be attractive at all.
Sometimes this work out with a good story, but often, it isn't attractive enough.
It makes one think that someone made a game for fun, instead of attractive as porn.
HTML games, that want me to open the site in my main browser, not the one used for porn, which I often always forgot select.
Vanilla sex, a hundred times over in a game.
Blow- and handjobs are in general just a turnoff, but some can pull this off (handjob on a woman is different, especially when it comes to molesting, that can often be a bit repeating before it gets dull, as long that story and and stages/molesting levels changes (could work for a femdom game to, but it's in general harder to pull off)).
It tend to work in some stages with male or female domination, but rarely in a vanilla story and many games reuse these scenes much to define it as a lot of scenes.
You really don't want to see these scenes very often.
Some like body/vagina hair, which I really don't.
Games where you have to hit many keyboard keys to get certain attack moves, when you're to masturbate.
Games with few save spot or none at all, where you have to restart or keep several game folders for different paths/saves
Harems is something I like/accept when the story is good, but they tend to be very bland in sex, similar (same with story) and can become boring.
A lot of games with development, long one, often suffer by this, likely due to the pressure to deliver results for sponsorship.
Eyes rolling backwards, often done with very large dicks being inserted. Instead of closing eyes and panting, they tend to turn me right away, ruining the scene.
Constant panting/moaning in very loud levels, compared to the talk during sex, you kind of needs that on a specific volume regulator or to turn off the characters voice with loud/extreme moaning. See it that you're watching a scene and you don't want everyone else to hear you or get deaf because someone is more or less screaming so loud, that you can't hear the others, due to that you have to lower the sound. Panting/moaning is not wrong, but it can sometimes or often, be at a level, where it starts turning you off and that you have to turn off the sound or skip the scene. Another issue, when the this panting/moaning is so much text that the scene-story barely progress and you have to smash a key to progress or skip and hope that you don't miss the juicy parts (you kind of have to hope that you can turn of the sound on this character).
Sometimes you wonder, if anyone did a quality check before sending the game through the different development stages?
Also a game without story or sex-scene story can be a real turn off.
Sometimes you have a story build up or that you have to battle a person in the memory room to get the story for that scene, that really cuts down on replayability and rewatching of scenes. A voice can do a lot of the erotic feel, however english dub voices or just plan translations, can be a real turnoff. Some games have really good images.
But I went straight to the memory room in the game Princess Honeypot I believe it was.
There was a few good scenes, but that kind of was all.
The game might be good, so I might play it, but first impressions, wasn't that good.
MTL tend to be another nightmare, however, it's sometimes necessary when you want to play a game.
But in these cases, if possible, a good idea would to be to just make some re-writing of the sex scenes.
Doesn't have to be accurate, just make it erotic.
Some think that animal porn, when characters are animals with fur are attractive, especially with no human involved?
Shrinking/making something larger, often makes the target so small and always at a very small size, that the sex scenes gets very repetitive.
This could easily be solved with different sizes, likely not done, because it would be harder to make these images and that means less content due to the time and skills needed. Stories of these games can often be very repetitive (same with images) or focus on grinding in the same kind of scenes and that do get boring quickly. Sometimes you wonder if the developer are trying to make porn for a specific genre, not meant for itself and lacking the interest to explore it and ask around (outside of the core-fans).
You often need to hear the negative critics, not the positive ones, to understand what something lacks and then try to understand the content in question. In some cases however, it's like "No, I have decided on how this game should be and I'll not change it", along with a squad of cheerleaders. Now some do take in information from all feedback, but in many cases you wonder if they don't see that it's becoming very bland? Vanilla only take you so far and then you need a very good story or gameplay to cater those groups instead. And it's one thing to add scenes later in the story, compared to going back randomly here and there (tedious for the player, unless a memory room auto-unlocks that content by progression).
Vore works similar with that above, it tend to be repetitive and often with the same images and few images for the scenes.
Vore require good scenes, if the general character art is lacking.
100 different paths, requiring replaying the game several times.
At these games, you just start looking for a save.
I'll be stopping now before the list gets any longer.
No offense to anyone and I know that it can be hard to re-write stories and programing instructions, especially if you work with set release dates.
However, sometimes you have to reevaluate some paths.