The game...
This has truly hooked me. Though the campaign is short lived, the multiplayer is great. I've had lots of fun playing with friends on this. A few improvements I would do:
Add more guns, or at least make more guns available for lower ranked people (You need to be rank 22 to get an LMG).
Add a chatbox.
Make the barricades a little more realistic.
Make purge easier. It is almost impossible (I say almost, because I have beaten it once, but I had to kill 1992 until the end, which was a waste of ammo).
Make shotgun and LMG ammo cheaper. It costs 25 dollars to get 200 bullets for an smg, but 75 dollars for 25 bullets on a shotgun? Honestly, make it cheaper.
All games have their flaws, but this game I liked so much. I can not rate it a 10, because if I did, that would mean there was nothing to improve on it.