How to beat Insane or Seriously Hard mode: You'll have to clear the game once on any difficulty (preferably Easy). Capture the Heliport or any other end that allows you to move 5 survivors into a new city. Choose 5 people and train them at schools so that they all have their skills maxed out (all of their skills). Move those 5 new people into a city on Seriously Hard or Insane mode. Now you depend on your strategy, but you'll have a very good team to start with, so you'll be able to quickly build a bigger fort and get more people. + This so people can see!
What if this was in the real world? Hahaha, "That damn neighbor let their dog poop on our garden again! Grab your chainsaw Kiddo, and you grab your Molotov bombs darling, we goin' to get them real good this time!"
Why are we humans so cruel? The story tries to tell you that humans are terrible, and even some guys post comments lik "I killed the family and escaped" Or "Just leave one alive"... Guys who post that... I HATE YOU!!!