What Lies in the Multiverse

• Chapter: 1
• Location: Milleville
• World: Dark (as opposed to the Light one)
• Requirement: stay inside the bar until the bartender shoots you
• Story-related? No; if missed on your first playthrough, you can use chapter select

In Milleville, right after the big red-leafs tree in which you get the achievement for listening the old lady story (Dear Julian), there's a bar where Everett is waiting for you.

Enter the bar, switch to the dark world by pressing and stay in sight of the bartender. He'll ask you to leave the bar a few times. He'll start to shout eventually. Simply don't move and he'll shoot you dead. Achievement should pop right away.

For a detailed walkthrough, check this video by YouTube user Carrot Helper (all credit to them):