A post-apocalyptic zombie strictly first-person shooter combined with the elements of an RPG such as Fallout, where you have skills to level up. Also MMO with PvP, safehouses to store loot, massive world, vehicles, and millions of items. Either find friends to make a gang with and loot some stuff, surviving and making sure you are hydrated, fed, and infection-free. Local chat only, say 10 feet talking, 50 feet yelling.
You also spawn anywhere in the world of your liking, and can make your way to anywhere else. So the whole world is dying, with the survivors as the gamers. Also, you took a test before you played that determined what job and social status you would've had, and what skills would have been affected :D
My dreeaaammm game<3
So like Left4Dead had love with Fallout 3, then made that game. That game both had babies with Fallout New Vegas, World of Warcraft, Left 4 Dead 2, then the hybrid of those babies had love with Call of Duty 4 and that baby then sucked gods richard.
That, my friends, would be the game.