So I've made quite a few sex games that have "gone viral" over the past year, and I'd like to talk a little bit about my experiences / practices. I would hesitate to apply these ideas to anyone else's situation, but it's what works for me, so here it goes:
Games are primarily conceptual / performance art; games are culture; it's more important to witness a game than to play it.
Most people haven't played most games. Conversations about games often start with "oh yeah I've heard about it" or "I haven't played that yet." Thinking about the vast intergalactic politics of EVE Online is so much more interesting than trying to play it, and watching high-level Starcraft play is much more interesting than drilling on a specific build yourself.
To "consume" a game, it is no longer necessary to play it. Rather, the most important thing about a game is that it exists, because that means you can think about it. (Or maybe, games don't even have to exist? Consider the endless press previews and unreleased games that engross so many people. These are purely hypothetical games that are often better than playing the actual finished product.)
The concept, and your explanation of that concept, and your audience's understanding of that concept, is your game.
How do other people talk about your game? As designer, you control much of that message and framing. When I make a game, other write-ups often rely on my own write-up; they embed my videos; they link to my screenshots. They are essentially repeating my explanation! And if your explanation sucks then the coverage will probably suck, unless the writer really likes you and will do the extra work of freshly explaining your game in their own terms. Talking about ___ can change what ____ is.
Generally, my games have a 5:1 ratio of page views to downloads, and that is a very conservative estimate that only counts viewers who actually went to the page. For the vast majority of the world, my games live as thought experiments or imagined games, not memories of actual experiences. So I think of my write-ups as artists' statements or commentaries or critical essays, but you could (less charitably) also call it "marketing."
Eventually, your ability to influence "what your game is" will slip out of your control. That's okay! That means other people are actively working on your game too, shaping it and bringing out new aspects of it -- that means your game is a shared culture, not just a product you're pushing around.
Explain the concept to yourself constantly.
I usually start drafting my game's webpage soon after an initial systems prototype, months before the actual release. Then I revise it once a week, and I let it change as the game changes in my mind. That's why it's called game development! Every rewrite or new batch of screenshots is a better way of thinking about your game that will affect how you make your game, and vice versa. Think about what makes for a good story or a screenshot, and that can help you hone what's magical about your project, and give it space.
That's how weird games are -- we make things while barely even knowing what they are. Your goal is to be really good at thinking about your own game, and to do that, you have to put in the work of thinking. Remember that there are many ways of thinking about your game, and writing is just one mode.
Invoke other games or cultural phenomena; your game is a piece of interconnected culture, not a walled garden.
Have you made other games that are similar to this game? Are there any other peoples' games that are similar to your game? Link to them, talk about them, and include them. This is how a "body of work" emerges -- someone has to see the connection and argue the connection, and that someone might as well be you. Things are always stronger together.
But keep in mind that this curation is work! I actively update my itch.io pages to link to my other sex games; I actively find press write-ups of my games and link to them; I actively play other peoples games and write about them, and try to connect them with my own tastes and sensibilities to try to facilitate a conversation.
We often think of game development as a technical discipline, but so much of a video game has nothing to do with code or technology. You don't have to release a software patch to update a game; all you have to do is to change how people think about it and interact with it. To totally murder this metaphor: your voice is the most powerful auto-update utility ever.
UPDATE 10/5: certain responses to this post are making me think that maybe I've done a poor job of explaining what I think is fairly obvious and noncontroversial -- that much of our everyday understanding of media is secondhand, and games aren't exempt from this phenomenon, and we should probably learn to be OK with it. I'm not saying "games that privilege firsthand play experience are bad", but rather I'm wondering, what if some games functioned better as cultural hearsay? What if you designed a game TO BE hearsay?
Matthew Burns tells me of the book "How To Talk About Books You Haven't Read" which makes a similar but much better articulated argument about literature and book culture. (I hope / presume Mr. Burns hasn't actually read it.)
I'm not saying people should stop playing games or something; after all, people still learn to play guitar and attend live concerts. Live experiences are great! But still, isn't it nice that we're not all expected to play guitars or attend live concerts? Isn't it nice that you can tell me about a band that I've never heard of, but tell me that they sound like Nirvana meets Beyonce, and I'll imagine that wonderful sound in my head?
This is how countless games already exist to us. When the time is right, maybe you'll seek out that fabled Kurt Cobain / Beyonce mashup -- and if the time is never right, then that's OK, you have millions of other things you could be doing. But if that possibility, that inkling, fascinated you for a hot minute, then let's be grateful for that moment and then move on with our lives, slightly changed if at all. It's what Beyonce would want of us.