Here is the full list of all 6 Off-Peak achievements. It takes around 1-2 hours to unlock all of the achievements on Windows.
You yoinked all the sheet music.
You listened to every piece of dialog in the game.
You ingested all the cookies.
You lifted all the records.
You ate all the pizza.
You didn't take anything from the train station that didn't belong to you (except the ticket)!