Frostpunk: Edition

To unlock this achievement you need to make the Shipwreck Camp, the Hot Springs, and the Children's Mine loyal to you. Your current relationship with each settlement can be found under 'Relations' by clicking on the Administration building.

To increase your relation with each, you need to make decisions that will please each settlement. These decisions will appear on screen much like other random events that happen in game. Most of the decisions that will please each settlement will also raise discontent at your outpost so be sure to keep discontent low by passing laws such as Public House, Fighting Arena, and Moonshine; and keeping homes and workplaces well heated.

Once you have reached Loyal relations with each settlement you will have to maintain them until the end of the scenario (although this won't require much extra work. Just make sure to keep selecting options that will please each settlement even after you've reached Loyal relations.) For my playthrough, I decided to save New London. I'm not entirely sure if saving New London or not is a requirement to unlock this achievement as relations with New London are always labelled 'Home City' regardless of what you decide to do. Once I had sent all the supplies needed to save New London, the scenario ended and the achievement unlocked.

This achievement can be unlocked on the easiest difficulty.