Abyss

Operation Abyss is an offical Zombie mode map in Counter-Strike Online.

Overview
Abyss is the first zombie mode map released in the game.It took place in the underground of the Rex Institute.The map is dark and with many obstacles.

Offical Description
Although the terrorists destroy the chemical and biological weapons laboratory research facilities successfully.However, this disturbance has also awoken the terror biochemical monsters which blocked in the depths of the basement...