Note: I take a VN as example, but this apply to whatever kind of game you want to make. It's just that it's easier to illustrate with a story, and easier to explain when you can illustrate.
Thank you for the great advice, I already caught myself doing lore dumps. I think it's a bad habit that came from seeing it in too many RPGM games.
The players who play for the story (around half of them) will be led by their curiosity ; they play because they want to know. Therefore, if you tell them everything right from the starts, what is the interest for them ?
By example, they need to know that in this universe females lead everything, because it would imply femDom and they perhaps don't like this. But why is the world working that way, is it permanent, are all males effectively submissive and all females effectively dome, is there a resistance, a way to not submit, and all this will be the questions that will make them continue to play. Of course, at one time all the questions will have had their answer, but they will have played half of your game at this time, or perhaps even more, and therefore already be really interested. Plus there's one question that will pop up during all their journey with your story: How does it end ?
Take the Lord of the Ring by example.
You can starts by saying that: "In a world where the land races are in a long and silent war against the cave races, you'll be the hero. One of the most innocent creature that exist, always underestimate but faithful to death, who inherited from his uncle of the long lost magic ring that once led the world near to his destruction. To get rid of it, in the heart of light worse enemy land, you'll party with Aragorn who, behind his rogue appearance, is a king, Boromir, who behind his nice personality, hide a twisted personality pron to treason, [...]"
But then, what left to the story ? By presenting the universe and the main characters, you removed most of the twists and most of the interest. The players who come for the story would finish the introduction and think something along the line of, "all right, I know everything now, no needs to read the book".
But wrote as it was, the thought will be, "wait, the fate of the world rest on this frail creature shoulders ?", "What ? This peasant is a king ?!!!" and other "oh my fucking god ! Why Boromir, why have you done this ?". And each time you've this kind of thought, you want to continue, because who know what other surprises hide behind the next pages.
Of course, you'll probably not write the Lord of the Ring kind of story, but it's the spirit you should follow.
I've been trying to cut down the word count to as few words as possible, I know people are just skip text in these games.
But there's another half who would find it too short. Keep it as reasonable as you feel it, without trying to please the players, because you'll never achieve this.
The only time where you really should cut off the word count is when it's narration. Show, don't tell ; a short scene will always be more impactful than a narration. It's why RPG Maker games are more verbose, because the engine don't really permit to show. But with Godot you can do it.
-plan out first 5-10 minutes of content to showcase potential/things to come
I'm not part of the majority on this, but I think that ideally the first release should be "two updates long" (with an average update length).
As said by GNVE and me, the most important point is to interest the player, and this whatever what can interest them (story or lewd). And it's not something that can be done in 5-10 minutes.
There's more than 13,000 games available, around 5,000 are works in progress, and globally there's ten new games started every week. Your first release need to have enough impact on the players for them to want to come back, even if it's just out of curiosity. And for this to happen, you have to give them enough content for them to remember that they tried your game.
Of course, it's more works. But since it's the first release, you have all the time you need. There's no pressure from the players asking for an update, since they still don't know that your game exist. Take benefit of this.
-quality promotional material (this I had not even considered)
As long as there's not a significant drop in the global quality after this, yes. Don't hesitate to really polish the first scenes, to seek for the most impactful, or at least the most relevant, approach for them.
You'll have all the game to tell us that the sister dream to be a princess, that the best friend is the most wanted thief in town, and things like that. In the first release, show us that the sister can become a Love Interest, and that the best friend will always help MC in case of need. Simply because it's what matter at first.
Having said that I currently just use the default Ren'Py UI. It is functional for what I want to do. At some point I might want to do something better but it is not my top priority.
You should change this and quickly. Even if it's just a temporary layout, having your own design for the UI will have a double positive impact.
1) From the player point of view, the default Ren'PY UI make your game even more generic. If even before you click on "starts" it totally looks like most Ren'Py games, they'll already believe that it will be yet one more generic Ren'Py games, this before they even read the first words.
2) From the creator point of view, it looks more impersonal. If you live in a house under reconstruction, you'll feel less the need to clean all the crumbs, even in the already finished rooms. It's the same for your game, if there's still some finishing touches to do, especially in the main interfaces, you'll feel less like it's your game, and will tend to think that "this scene is good enough, I'll probably come back on it later" ; but you'll never come back on it.