Zombies are not the only Enemy

With civilisation as we know in collapsed, so to have the security checks and measure over other toxic chemicals being stored around the world.

Gangs of nomadic survivors roam the land attacking zombies and other survivors alike.
Pockets of survivors hold out in fortified towns keeping anything attempting to get into the towns at bay to prevent infection. They also compete with other survivors for supplys needed to stay alive.

Military units from other nations have also formed teams that may or may not be friendly to the Reaper Teams.

There is also no telling what other disaster the world will face in the near future.

Giant radioactive creatures, other types of undead or mutated animals ressembling the horrors out of mythology may all be out there waiting to feast on the remmenants of man kind.

Basically this will give me the chance to throw in some werewolves or other nasties to give a change every now and then to the average game.