Anniversary of the dead
Complete the Final Day, in either Single or Multiplayer, and finish the game
45 
A Week To Live
Complete 7 days in any game mode without dying
25 
Hotter Than Hell
Complete the final day of the "7 Days of Hell" unlockable mode
25 
Can't Touch This
Rack up a 100x multiplier in any game mode
20 
Friends in Low Places
Save 25 survivors in any game mode
20 
Interior Decorator
Kill 25 zombies in any game mode using environmental hazards
20 
Tour of the City
Complete each arena at least once in the same game in any game mode
15 
More the Merrier
Kill 10 or more zombies at the same time in any game mode
10 
Environmental Awareness
Kill a zombie using an environmental hazard in any game mode
5 
Gas Powered
Complete an entire arena, getting every kill with the Chainsaw
5 
Gun Shop
Kill at least one zombie with each weapon type in any game mode
5 
Socialite
Play in an online multiplayer game
5