Mission introduction | Mission 5:
Below the Thunder Crysis Warhead Guide

This is going to be a very unique mission. You'll operate underground right until the end. It means you may have some problems with orientation, because you won't be able to use your personal map. Thankfully, you won't encounter any nanosuit soldiers and it'll also be fairly easy to surprise enemy units. The only exception is the final part of the mission where you'll have to go against larger groups of Korean soldiers.