If you ever have the time, I’d love to hear how you wound up navigating the game and what routes you ended up getting in what order, especially without using the walkthrough.
I'll try to do this now, while it's still kinda fresh in my mind (I basically binged the whole game over two days), before I start on those achievements.
So, first run. I named my native girl Tris (dunno why, just first thing that came to my mind after I figured there was no default like in some VNs, I suck at naming) and went to look for other survivors. Since I later always reloaded to the first choice instead of starting a new game, the name stuck for all the routes.
Now, on the beach I must say I (initially) missed all of the branches that require you to tell Bobbi that there was a native, but that you are probably alone. On my first rune I went with "there is a native" and "I'm sure someone made it" (those would be "my choices"), and later on I tried going full "we are alone" with the predictable effect of sex with Bobbi, but I never figured to try that combination.
Then I went with Melendy to check the fires, enjoyed the sex zombies (always a fun concept and I really liked your implementation and explanation later), and went through the machine myself. I stayed with Regina (Mort is a good guy, didn't feel like stealing his girl) and got frustrated with the choices (since apparently there is no good way to do it?) and then went to the orgy, mostly since I wanted to know what caused the zombies.
That was my first try. From there I experimented with variations of this route (I usually save at major choices, then once I get an ending, I go back to the last choice, etc.), then the one where you fuck Bobbi at the start, then with the route where you follow native girl. I went back a choice every time I ran out of options, though I didn't save at
every choice, more like every 2-3, also depending on the nature of the choice. It should be rather easy to see (especially from your perspective), which routes I ended up on.
That's my general approach to typical VNs with many choices (obviously doesn't apply to games with clear route flags, or very few choices): first go fully through using choices I find correct or most fitting for me, and then backtrack starting at the end (kinda ends up being a depth-first search of a binary tree, now that I think about it). Obviously I don't check
every possible combination, especially in a game with as many choices as this one, so I missed stuff where it wasn't obvious that choosing something differently early on would change something much later.
Also as I said I completely missed the major branch where you go to the cave with Bobbi (and all the resulting routes), until the walkthrough brought me there. Then I explored by myself from there until I ran out of obvious paths again.
I think if I don't count the endings I figured myself after being led to that additional branch then I needed the walkthrough for maybe, hmm, 7-8 endings? I don't remember exactly
I still don't
get how some of them work, for example what specifically splits the two different "crazy future MJ" endings ("Dad End" and the other one), especially since for those two I think the walkthrough takes drastically different paths. This game has some really complex relationships between choices.
I hope you don't have anything against me possibly un-ren'py-ing the game (assuming it's doable) after I get everything to look at the inner workings. I'm a programmer and I love looking at ren'py game scripts (after completing them, out of curiosity. not to cheat/etc.) I still have DDLC decompiled stashed somewhere.