Counter-Strike Online is a remake of Counter-Strike: Condition Zero targeted towards Asia's gaming market. It is being developed by Nexon Corporation with oversight from license-holder Valve Corporation. It uses a micropayment model that is managed by a custom version of the Steam back-end.

Counter Strike Online features the same weapons that have appeared in previous installments of Counter Strike, but further supplements these with some new weapons, such as the K1A and the QBB-95 and new player models. In the case of Zombie mode 2, fictional specially-remodeled weapons such as Double MP7A1, Double Night Hawk(Desert Eagle), and CV47(AK-47)-R60 appear in supply boxes, fallen from the sky, which only appear in Zombie mode 2.

Counter Strike Online features four game modes compared to the original: Death Match, Team Death Match, Zombie Mode, and Zombie Mode 2.