Alright, let's get you started with some early constructive criticism.
For one, your structuring of the OP is't bad, although there is never any harm in getting a few pointers from users with past experience in post formatting. A logo would also be nice, too, since it adds that much more to the feeling that you're actually putting effort into your work. Again, though, you did pretty good.
I personally think that, although your story is a good concept, there are things missing.
What exactly caused the world to "fall into chaos"? Did a nuke go off, or some scientists had accidentally released a mutant vampire werewolf disease? Plus the entire world went to stuff in this scenario. If it happened on such a major scale, you should have the backstory on what caused it all.
What kind of setting will roleplay primarily take place in? All of our major, popular roleplays (Portal's, Cysero's, Minomato's, etc.) usually have a setting within the confines of a city, region, or at the most an entire country. It would be rather tedious to have to build an entire continent, let alone several, for a roleplay. I myself would try and shoot for a smaller area in which this takes place; maybe we can focus on the survivors in Germany? It doesn't even have to be a real place, either. You're the writer, your imagination's the limit.
It seems to me that you've set up the roleplay in such a way that it follows just one protagonist or group. As I said before, pretty much all other roleplays are set in a specific location that doesn't change. It would get a little tedious constantly changing settings.
Now this "Delta Force DLC" is a really big problem. A roleplay blossoms when the users contribute their pollen -- which is to say it builds a story around several players, not just one. The way it's written makes it sound like we'd be playing a single-player RPG as opposed to an RP. I would suggest that instead, you can have certain events planned out and played by the admin team, within the setting. Mind you that every character has a very different personality, and have different reactions to everything. This is the blood of roleplay, and is without a doubt one of the most interesting factors.
(By the way, DLC stands for downloadable content. It's only used in actual games, and it's literally extra content that you download, and more often than not, pay money for. Doesn't really fit in a roleplaying server.)
It's also a very good idea to brainstorm on how exactly your RP will work. Will we be fighting mobs of frothing bandits looking to cause chaos and unrest? Will we be trying to explore new places and rebuild society, or just try to work together and survive?
That's all I've got for now. Best of luck, a serious roleplay is hard work. Give it your all and you can make this happen.
