I figured out how to fix the achievement if it's not working. Before you get on the train to finish the game, hold onto a leaf blower, (for future speed as you will respawn with it) then once it restarts after finishing the game, speed run through all the characters again including getting the ticket again and you'll get the achievement then when you see Dragojevic as the last person. Worked for me!

Works on Linux with Proton, got infact all achievement

I talked to everyone but no achievement.

Thank you for this,

I love you

just watched this video and turns out I already talked to everyone on my very 1st playthrough but didn't get the achievement :<

I can confirm that the achievement popped for me after talking to everyone (in no particular order) in one play through without exiting the game. I got it on my second run without resetting the game or reinstalling.

i have, if you read the comment history :D

Ah, OP you've made a mistake. The door guard is NOT an extra, and is required for the achievement. You might want to point that out.

seems like it works for some and doesnt work for some. could be bug. i have no idea.