Anniversary of the dead
Complete the Final Day, in either Single or Multiplayer, and finish the game
45 ✓ January 1st, 1753
A Week To Live
Complete 7 days in any game mode without dying
25 ✓ January 1st, 1753
Can't Touch This
Rack up a 100x multiplier in any game mode
20 ✓ January 1st, 1753
Friends in Low Places
Save 25 survivors in any game mode
20 ✓ February 23rd, 2010
Interior Decorator
Kill 25 zombies in any game mode using environmental hazards
20 ✓ February 21st, 2010
Tour of the City
Complete each arena at least once in the same game in any game mode
15 ✓ February 21st, 2010
More the Merrier
Kill 10 or more zombies at the same time in any game mode
10 ✓ February 21st, 2010
Environmental Awareness
Kill a zombie using an environmental hazard in any game mode
5 ✓ February 21st, 2010
Gas Powered
Complete an entire arena, getting every kill with the Chainsaw
5 ✓ February 22nd, 2010
Gun Shop
Kill at least one zombie with each weapon type in any game mode
5 ✓ February 23rd, 2010
Hotter Than Hell
Complete the final day of the "7 Days of Hell" unlockable mode
25 
Socialite
Play in an online multiplayer game
5