Counter-Strike: Condition Zero preserves the same gameplay mechanics of the original Counter-Strike game and it runs on the same engine.
Single Player & Condition Zero: Deleted Scenes
New to the series is the introduction of a single player, a series of events divided into several missions, where the player faces AI controlled enemies. As the player passes certain requirements for each map, the unlock new maps and more efficient bots.
Additionally, a bonus of 18 unconnected single player missions, the work of Ritual Entertainment's contribution to the project, was released as Condition Zero: Deleted Scenes.
Bots are another new entry to the series, which populate any online or offline game as another player. The AI is more advanced, acting like a real player, and serves as a filler in the cases where the player can't go online or has difficulty finding people to play with.
The game retains all of the game modes found in Counter-Strike and adds up a new mode called Assassination.
In this new mode, one of the Counter-Terrorist players starts as a VIP and has to be protected throughout the entire map by the rest of the team from the terrorists, who need to avoid the VIP reaching the safe zone. VIP's can only buy limited amounts of weapons and if they die the round is lost for the counter-terrorists.
In Versus, the two teams face each other until one is eliminated, awarding the surviving team with the victory of that round, or until the time runs out, ending in a draw.
In Bomb Defusal, Counter-terrorists win the round by successfully protecting one or multiple bombing sites until the time runs out, or by defusing a bomb once planted. Terrorists win the round by successfully planting and detonating a bomb, which has a set countdown, or by killing all CT members while the bomb is planted. Victory may also be achieved by any team if the opposing team gets eliminated before the bomb is planted.
In Hostage Rescue, Counter-terrorists win the round if they successfully rescue all hostages before time runs out. Terrorists win the round by preventing the rescue of all hostages. Alternatively, victory can be achieved by eliminating the opposing team.