Counter Strike Online Wiki
Bot Zombie Mod
Bzm bigtree cso.png
Big Tree

Big Tree (bzm_bigtree) is the first Bot Zombie Mod map in Counter-Strike Online.


Big Tree is the first map that supports the Zombie Bot game mode. It promotes to basic Zombie: The Original system with the addition of bots. Bot navigation has been tweaked a bit so that it is compatible with Zombie modes. These modifications to bots are:

  • New function: zombie safe area.
  • No attack delay to all bots.
  • If one teammate is infected in a camping area, other human bots will rush to another safe area. There are two safe areas for bots in this map.

Release dates


This map was released alongside M32 MGL on:

  • South Korea: 28 June 2012 with Z-VIRUS patch.
  • Taiwan/Hong Kong: 4 July  2012 with Z-VIRUS patch.
  • China/Japan:  4 July  2012 with Z-VIRUS patch.
  • Indonesia: 10 April 2013.


This map was released alongside SKULL-1 on:

  • Singapore/Malaysia: 27 March 2013.


This map was released alongside MG3 on:

This map was released alongside Open Beta Test on:

  • CSN:Z: 23 September 2014.
  • Vietnam: 26 March 2015.


Special mission

Appointer Task Reward
Felix.png Kill 30 zombie bots in one day period.

Random cash weapons for 3 days or Level 2 Experience coupon.

Honor mission

Title Description Task
A medal will be given to the player who has unlocked the Difficulty Level, Elite, in Bot Zombie mode.
[Bot Zombie Master]
Gentleman, you shouldn't belittle on them just because they are dead. Don't forget they are zombies. Unlock Difficulty Level, 'Elite', in Bot Zombie Mod.



  • In the tunnel there are rats and bats; the bats will fly out once any player enters it. Near the big tree, there are also a few rats which can't be interacted with.
  • The rats model is taken from a cut model in Half-Life, while the bats model are taken from Banshee's Pulling ability.
  • This map is used as a tutorial map for Zombie mode.