Reaching an ending ยท Days 71 to 100
Which ending, what does it need, and by when?
The endings your character can reach, the targets each one is measured against, the day the choice closes, and the achievements worth planning a run around.
Every guide here is checked against the 9/2 Update (version 1.0.15511).
Start with this one
It answers the question the rest of the stage builds on.
Every ending, and how the game decides which one you get What are the endings and how do I get the one I want? The decisions, in the order the run poses them
Each one gives a default choice, the reason, when it holds, what it costs and what to do instead.
The three endings you build for, and the exact targets What do I have to build to keep an ending open? 
The endings that need someone else, and how to keep them open How do I save the neighbour, and what do the people endings need? 
The last thirty days: what is left to do after day 71 The story seems over. What am I doing for the last thirty days? How it works
The rules and formulas behind those decisions, with worked examples, and how to use the lists.
Look it up
The lists a player at this stage keeps open. Each one works on its own, without reading anything.
Endings 
Characters 
Achievements