It All Dies Achievement - Weird West
10End the world. 90g.
This achievement is earned at the very end of the game in Chapter 5 as the Oneirist. You'll reach a point in the story where you have to follow your brand, which leads to a little house in "Foxglove" - I suggest creating a save before entering Foxglove. You can use this save to complete the second ending afterwards.
To get the "Bad" ending you have to show no emotion in your answers. Picking the most heartless options that you're given. The questioning only truly begins when you (Return to your body). Anything before this is just story narrative. Here are my answers:
Q: So, what I want to know is why? Why didn't you help those ghosts?
A: Say the plights of mortals mean little when all is said and done--we all turn to dust.
Q: It was fine huntin' you did, a good heap of bounties. But ain't it ever bother you? Ain't you ever wonder if you was right to call yourself judge, jury and executioner for them folk?
A: Say they would've faced judgement no matter what, by your hand or another's.
Q: Imagine that? You made friends. I'd laugh, if I could. Tell us--what do you think of their loyalty to you?
A: Say loyalty is meaningless.
Q: So--why'd you do it partner? Money worth that much to you?
A: Say the money was nothing more than shiny metal to you.
Q: I'm dying to know--did you enjoy it? Regret it? What's in that heart of yours, huh?
A: Say life has no inherent value--all lives are meaningless, in the end.
Q: Now, answer: did you use their lives well? Were their lives worth living?
A: Say their lives are as meaningless as all others.
Essex options:
A: Tell him his life will turn to gust, like everyone else's.
A: Kill Essex--for his own sake.
This should give you the bad ending and the achievement should pop as the credits roll. Please note some of the questions might be different as they try to tailor it to your experience.