Renegade Ops
15 Achievements
8-10h
Extraction
Mission 1 - Rescue all the civilians (Coldstrike DLC required)
2.1%
How to unlock the Extraction achievement in Renegade Ops - Definitive Guide
EDIT: Easy, just did this on hardcore with skill level Alien. The whole game seems so easy when you have completed the main campaign solo on hardcore.
Now this one is a pretty easy trophy to acquire if you correctly follow the steps that I'll list below. Near the middle of mission 1, there will be a part where you have to rescue the civilians from their frosty cages. They are probably hidden in static so they're hidden in questionable blue looking closets. When you start rescuing the civilians and you hit the 6 civilians rescued mark, you will be prompted that a golem has appeared in the nearby village and you have to stop it. The first thing you have to do is completely ignore the golem and continue collecting the civilians until a timer appears.
What'll happen when you do this is, the timer will reset and disappear when you kill the golem as the timer and red objective marker has prompted. So after that, continue collecting the prisoners. You will be prompted to defeat atleast 3 golems before the mission ends so it won't be a problem if you abuse the button all the time and switch between parts of the map to return and collect. There are 24 civilians in total. Also remember that the three other civilians only appear when you've defeated each of the golems so don't panic when you're at the last golem with only 23 civilians!