I managed to unlock everything from chapter 1, but couldn't in chapter 2.
*sight*
The summaries are not a list of goals to reach, but a reminder of your actions during this chapter. Not checking all the marks is totally natural
and expected.
I suppose that you don't know that there's two summary screens, one for the male MC and one for the female MC, and that they don't have the same list of events. What mean that right from the starts you haven't unlocked everything, unlike what you believed.
The updates do take long, but after each newer update, I am getting less and less content, because I didn't have the correct prerequisites,
No, you are not getting less content than in the previous update. Picking the right option will give you access to extended scenes in the future, but not picking it will not deprive you of the common scene, that will be more or less as long as in the previous chapter.
meanwhile the updates are taking longer and longer, because each branch is involving into newer subbranches that keeps exponentially needing more work to be done.
The delay is not due to each branch involving newer subbranches, because there's no subbranches. Either you did it right and will continue your journey with the girl, or you haven't done it right and you'll still have the possibility to hang out with the girl.
What made the delay be longer between the chapter 3 and chapter 4 is the addition of the missions, what increased the content for everyone during the free roaming part. As for this update, it's due to a car crash that let Notty injured and not able to effectively and efficiently works on the game for a bit more than two months.
So it results into less content for me, and more work to the developer.
Still no, not less content for you. As for the amount of works, it's the same for every single dev on the scene who isn't doing a pure kinetic visual novel.
[...] it also ends up that I simply cannot find everything, doesn't matter how I try to get a 100% run.
And so ? What's the problem exactly ? It's not a pokemon game. Not only you don't need to catch them all, but anyway you can't catch them all, it's totally impossible.
This impossibility is made obvious really early in the game. Either in the chapter 1, when you've to choice between Sarah's VR game and Sarah's Caverns of Creatures, or in chapter 2 when you've to choose between a night with Chris or a night with Annie. And if it wasn't obvious enough, the night screen will present you more than one option, letting no more doubt regarding the fact that you can't get all the content in a single play.
This being said, it's the same for most games available on the scene. It's not because you don't know it, that you haven't missed tons of content in them.
[...] I can't unlock everything, even if I wanted to.
No one can, and globally no one care.
If I cannot get 100% from a path that I've selected, then maybe there's something wrong.
Yes, there's something wrong: There's no paths to select.
What you select is with who, and with sarah how, you'll occupy your nights on Ophion, nothing more. At no time there's a guaranty that you'll have more than a hang out scene with the girl you picked. Read the room (therefore care about the dialogs), in order to not mess it up totally, and you'll be able to continue your journey in the next chapter, that all.
