Unlock the following modes by performing the corresponding tasks:
MODE - HOW TO UNLOCK 7 Days Of Hell - Beat Day 55. In this mode will be seven very long levels. All Weapons - Beat Day 55. In this mode you will be able to use all weapons and have infinite ammo. Blackout - Beat Day 55. In this mode your view is shrunken to a small circle around your character. Radioactive zombies will become more visible. Chainsaw Mode - Beat a level using only the chainsaw, and without any environmental or Zombie Bait. In this mode you will be limited to the chainsaw and Zombie Bait. Hardcore Mode - Survive seven days without dying. In this mode you will only have one life. Turbo - Get a 100x multiplier. In this mode everything will move faster.
ACHIEVEMENT - HOW TO UNLOCK Environmental Awareness (5 points) - Kill a zombie using an environmental hazard. Gas Powered (5 points) - Complete an entire arena, getting every kill with the Chainsaw. Gun Shop (5 points) - Kill at least one zombie with each weapon type. More the Merrier (10 points) - Kill 10 or more zombies at the same time. Socialite (5 points) - Play in an online multiplayer game. Tour of the City (15 points) - Complete each arena at least once in the same game. Can't Touch This (20 points) - Rack up a 100x multiplier. Friends in Low Places (20 points) - Save 25 survivors. Interior Decorator (20 points) - Kill 25 zombies in any game mode using environmental hazards. A Week To Live (25 points) - Complete 7 days in any game mode without dying. Hotter Than Hell (25 points) - Complete the final day of the "7 Days of Hell" unlockable mode. Anniversary of the dead (45 points) - Complete the Final Day and beat the game.