Alright, first off I know it's a video game, secondly, I want to see as little Zombie, Mutant, or Abomination of science as possible in this thread. So if you think that's how it's all going down, please do not post about it, you already have a Topic I believe they call it Enemy Choices, go back to the delusional fantasy world lol. (On a side note, nothing against Zombies, just need something different, something realistic)
Now, I'm going to put one idea in, I hope to see more appear as time passes by! :P Just think of your everyday life, and what it would be like if it crumbled to dust almost literally! Think about how you would live, what you would look out for, what dangers would be present. It could be everyday things! Gas lines underground suddenly sparking up into an inferno because of sparks caused by a power box overloading or something. Anything that would pertain to the real world!
I am going to say for my own thought of a threat in this new world, finding a safe place to sleep for the night! Somewhere you won't wake up with a guy standing over you, dressed as a hobo, ready to pummel your skull with a chunk of concrete. Or worse, someone stealing your water and food while you sleep, leaving you to die with nothing to use!

Well it depends of course on what the disaster is. Since it has taken no less than 6 days for people to be openly robbing eachother (which is very different from stealing because there is no confrontation in theft) one should assume that this is no simple earthquake. At least realistically. The entire US society must of been toppled; the people in Chicago, ground zero or not, expect no help from the outside for the immediate future.
So if this is some kind of giant natural disaster (or government conspiracy since it will seem like a natural disaster to the general population anyway, like nuclear explosions underground) then
1. Large stores of food, water, and other supplies are most likely destroyed.
2. Survivors will most often be found in groups because which ever areas were safe enough for the disaster (or beginning of the disaster) will house the groups of people who were there. Basically since there are large areas where relatively unaffected, all the people in those areas would become a group of survivors. That's realistically though, the game developers might not make it that way.
3. Appendixes will burst, broken bones will go unmended, people will die from toxic metal poisoning, things will explode. Chaos.
4. I'm not really sure how people will secure food...I'm assuming the disaster was big enough to basically collapse the entire city, even if it didn't do it immediately. So places like Target or grocery stores will be mostly inaccessable, and even if a few are still there, it will only be a limited resource. I'd say people should run to the hills.

I am either going to love this game or absolutely hate it. I hope that it is as close to realistic as possible. No zombies, mutants, or anything else like that. Your only enemies should be other humans, pets gone wild, the environment itself, and your own choices. (Which I guess ties all those together) Oh please let this game be good.

I think one thing that can replace this monster or creature horror concept is 'Cannibalism'. In a situation like that where there is no food or water , people can turn cannibal. Also this could be more realistic as per as the horror aspect is concerned.