Here is the full list of all 31 Zombie Kill of the Week - there are Reborn achievements.
Get a shotgun, and make 20 zombies crawl in front of you.
Go see your friends!
Survive 4 minutes in Area 73. (Challenge mode)
And still going?
Survive 4 minutes in Homerun. (Challenge mode)
Survive 4 minutes in Night At The Mall. (Challenge mode)
Survive 4 minutes in Arise. (Challenge mode)
Get 5 meats in a single game from the fridge.
Find the fridge and make it disappear. Repeat 3 times.
Survive 4 minutes in RedSnow. (Challenge mode)
Get promoted to rank 30.
Encounter all 3 tanks, and get them killed.
You have wasted 5 hours of your life.
Own atleast 5000$ in one match
Slaughter 10 000 zombies in total.
Open all areas in a single match.
Fight your way to round 20.
Survive 4 minutes in Abandoned Hospital. (Challenge mode)
Stand still for 30 seconds, wondering about your life.
Slaughter 5000 zombies in total.
Get 100 headshots in one match.
Slice 53 zombies in one match.
You have played ZKW for an hour.
Get the GiGaGirlGannon, and kill 10 zombies within 10 seconds.
Help your friend in need.
Get yourself killed with a grenade. Dumbass.
Kill the zombie bear before he takes your money.
Grill 50 zombies with flame in a single match.
Kill 15 zombies with a katana, and 25 with saw in one match.
Get promoted to rank 10.
Zombies are not ment to fly.