Some bug is causing the unlock displayable to show who that option belongs to even when the actual content isn't unlocked, I'll get to fixing that during the weekend. As for the condition to unlock the bonus chapter, you need to have done Chloe's scene in chapter 3.1 and chosen to "aim for something more". After that, finish chapter 4 and you'll be prompted to play the new bonus chapter right after, and if you choose not to, it'll be unlocked in the "extras" menu. For anyone wondering, the "unavailable" option is the gallery system that I haven't finished yet, hence why this update is marked as "WIP".
Well, though there's no doubt I've indeed gotten better since I first started (you can compare my older renders to the latest ones), my hardware hasn't. The game just gets progressively harder to make and update. My CPU, for example, is threatening to bite the dust any day, now.
And I'm sorry I haven't had the opportunity to update the main plotline, but let me clarify to everyone that "bonus chapter" is just semantics to differentiate what is normal gameplay, and what is not. It contains just as much substance and player choice consequence as normal gameplay does, it just has a different name. As a matter of fact, what happens in the bonus chapters heavily affects the main story, as you'll witness in Chapter 5.
Apologies for that. I'll be working through the weekend to fix that once and for all. It has afflicted all of us long enough.
So... if a game doesn't tickle my pockets I should just... abandon it? What kind of logic is that? I've released a normal-sized update, by the way. It just contains "WIP" in its name because I don't wanna gaslight my player base into forgetting I've been promising the gallery system for two years at this point. The actual update I've released has been ready for two months, the extra development time has been put towards finishing the redesign of Elena's first +18 scene, which I didn't have the chance to finish and put out because of circumstances out of my control. You can read the details on my Patreon page (and I want to remind everyone that most of my posts are public).