Counter Strike Online Wiki

Thank you for your help during the zombie outbreak. Thank you for experimenting! Urge them to see the results quickly this time. Confirm the scale of the experiment! The experiment is okay. It will take place by day and night in this city. Named as Z-City! Good luck! That's all for this experiment. Maybe you should familiarize yourself well to survive!


This is a mode in which all players become enemies, killing opponents and surviving. The game ends when the last one is chosen as the final survivor. When the game starts, it does not have any equipment. But do not panic! Find items scattered throughout the city to collect items for survival and growth.

  • The spread box can be opened with the E key. If the item drops to the floor after the box is opened, pick it up with the E key.
  • You can check the items you have acquired by opening the bag with I key. You can use it by right-clicking the item.
  • Z can help you survive at any time.

At night, zombies become stronger and you can get a variety of items by killing zombies.

  • When attacked by a zombie, it infects the virus with a low probability, and the infected player turns into a zombie at night.
  • Player zombies are only capable of melee attacks, infecting opponents can take up to three mutations.
  • Player zombies return to humans in the daytime.
  • After a long period of time, the map is filled with gas, resulting in reduced health and powerful zombies. Only the hiding is not the shortcut of victory.

Update 23 February 2017[]

Z City Time will add a daytime weapons shop.

  • Melee weapons / equipment can not be purchased.
  • When purchasing weapons, please use the E key to learn the items fall on the ground. (You can acquire others.)
New Displacement
  • Bomb Interceptor (Z City / Zombie Z Zombie Only)
    • Destroy enemy team projectiles with a certain probability. Normal bullets can not be destroyed. All functional bullets are invalidated. (Flare / cooling shots / vaccines Tan / smoke, etc.)
  • Unstable mutation (Z City / Z zombie zombies, humans only)
    • Obtain every round random mutations. (In Z City, every day / night is changed.)
  • Variations obtained through unstable mutations are retained for only one round, but the effect is more powerful.
  • A special shot (cold shot / vaccine shot) obtained through unstable variation will disappear if you remove the unstable variation.
Z City Change / Improvement
  • Z City-only map "The Mean Distance" has been expanded.
  • Every 3 days of in-game time will be changed so that you can re-acquire items in some boxes.
  • In the 5th day of in-game time, energy curtain occurs and map is gradually reduced. When you touch your body, your physical strength decreases.
  • Bombardment Zombie / Albert / Zombie Zombie Ranges: The attack changes to prevent damage through the wall.
  • Kevlar / Emergency relief tool will be improved to drop.
  • Z-City will be improved to receive random compensation after the end.
  • Zombies are added to drop rare items. These zombies appear with a very low probability.
  • Improved to use emoticons in Z City.
  • City exclusive firearm M16A4 M203 has been added.

Update 9 June 2017[]


Z-City 'Dirty Street' map is expanded and 'Vehicle' function is added.

Update 17 August 2017[]

Z-City Duo

Dr. Mad's survival experiment begins. Now the last survivor is not alone. In extreme situations, humans come to the test bench to see if they can cooperate.

  • Z City Duo can join two CSO2 parties in the game lobby.
  • If you enter by yourself, you will have two teams at random.

If the other player is too strong, you can spend time in hiding and gradually gain abilities, or hunt weaker opponents to gain experience and gain experience. But be careful, if you spend too much time in a pointless way, you do not know what an angry Doctor Mad will do.

  • If all team members or even one survives as the last survivor, they will win.
  • If you have less than 4 players in Z City Duo Mode, the game will not proceed.
New map Death Valley is added.

Update 31 August 2017[]

Increased vehicle damage outside the safe zone

There was a play method to secure the survival time by alternately riding the vehicle using the durability of the vehicle. This makes it more disadvantageous for players who are actively engaged in combat. In order to prevent this, we have improved the amount of damage when you are outside the safe area while you are in the car.

Fixed bugs when dropping inventory items

Fixed an issue where items occasionally disappear from the bottom when dividing items with team members.

RPG-7 performance improvement

Increased explosive range and power of the RPG-7 to suit rare ranks.

Modify variation balance

The sniper rifle weapons were too powerful and many were unable to respond to enemy fire. So we lowered the power of the mutations associated with the sniper to control the impact of the sniper rifle.