I would say that generally speaking no matter what the tags, I think any game/VN can be successful and well received. I think it is far more important that the story is well written and entertaining, the character development/arcs are solid and believable, and the characters actions (including the MC) are plausible within an acceptable degree of suspension of disbelief. That said I am open to most tags with the exception of scat/gore/vore which I will avoid like a plague and Futa/Trans/Gay which I will steer away from unless its avoidable, and not at the expense of the story.
The tags I suppose I gravitate to most without any noticeable waning interest would be:
Staples:
Vaginal Sex: This one is usually a must for me with male protagonist games.
Romance: Not needed for every girl in a game, but a game where none of the girls want/need some romance is not a game a will care about.
Pregnancy: I like it in the story. I like it even more if it's actually a part of the story and not just some picture you get at the end of one of the "choose your own adventure" paths.
Incest: It's taboo and can be well done, but as has been stated numerous times already, it gets significantly less fun very quickly the less believable it is. "Oh my mom's nipple just peeked out of her robe I must focus all of my attention on getting her in bed now cause I never realized how hot she was till just this moment!". I think incest should be all about the buildup and feasibility of the scenarios… basically I prefer the idea that the perfect storm of events could happen over time that would make Relative A actually develop real romantic emotional desire/fall in love with Relative B, as opposed to just carnal lust which I find less interesting in an incest plot.
Lesbian: I am not
usually as much of a fan of female protagonist games so it works best for me if it's between other characters and I also prefer there to be genuine emotional attachment from at least one of them and not just "Ooh lets experiment! That seems like fun!". That being said if it is a female protagonist then I prefer the lesbian archetype.
Multiple Endings: I like to feel as though the choices I am making have at least some impact on the direction of the story.
Treats:
Mind Control/Sleep Sex/Corruption/Drugs: When done right, can be truly entertaining.
Harem: Only works for me if it actually makes sense… or at the very least not a complete stretch of imagination, but if done right I enjoy it.
Cheating: I think that it can add significant drama and emotional attachment to characters when its properly implemented.
NTR: Yes I said it, when its done right it can be truly entertaining. I can enjoy it if its used to create negative emotional connections to a character or characters, as a part of a 'believable' cheating subplot. I generally do
not care for it if its done in a manner that expects the MC to turn a blind eye to it assuming they know its happening, or even worse stand in a corner and jack/jill off to it because it excites them.
Exhibition/Humiliation/Urination: In moderation… I'm not generally interested in a game that focuses on any of those things but if it just happens naturally
it can really heighten my interest in a game.
Rape: If it's done by the MC I think it needs to have a significant reason behind it and not just "She said no, so I'm gonna make hur regret it!". I usually prefer it to be optional and perhaps not even something the MC is doing at all.
There is probably more but I just noticed how much I have already rambled so thats enough for now.
