Its not random. Winning battles increases the detection; later chapters require more battles to get to 100%. When you beat the NEW boss thats revealed at this point, you move on to the next chapter.
I'm only at chapter 4, so will there be choices at the end that will affect the ending or is it based on how many casualties? Also if it's not for the ending any other impact for having many casualties aside from extra $$$
As I test, there are three endings about the world situation. They are base on casualties, not exactly know the numbers, but one is zero and one is lots casualties. You can check public feeling(worried, disgusted, hated) in mission statistics(computer screen). I think they all lead to one world situation ending.
Wow I got to Chpt.9 and just had those nukes hand it to me. I'm pretty powered up but energy and health management are as critical as taking the nukes down before they're within the 1st radar range or else u get crushed by the 2nd one.