Counter-Strike(CS) is a series ofmultiplayerfirst-person shootervideo games, in which teams ofterroristsbattle to perpetrate bombing, hostage-taking or assassinations andcounter-terroriststry to prevent it. The series began onWindowsin 1999 with the first game,Counter-Strike. It was initially released as amodification("mod") forHalf-Life.

Counter-Strike was followed by Counter-Strike: Condition Zero in 2004, developed by Turtle Rock Studios. In the same year Valve Corporation released Counter-Strike: Source and became the first in the series to run on Valve's newly created Source Engine. Then Valve released the fourth game in the main series in 2012, Counter-Strike: Global Offensive for Windows, OS X, Xbox 360 and PlayStation 3.

Counter-Strikeis an objective-based,multiplayerfirst-person shooter.
Two opposing teams—the Terrorists and the Counter Terrorists compete in game modes to complete objectives, such as securing a location to plant/defuse a bomb and rescuing/guarding hostages.At the end of each round, players are rewarded based on their individual performance with in-game currency to spend on more powerful weapons in the next rounds. Winning rounds results in more money than losing, and completing objectives such as killing enemy players or planting/defusing the bomb gives extra cash bonuses. Uncooperative actions, such askilling teammates, results in a penalty.

There are five categories of purchasable weapons, four being guns and the final one being utilities:pistols, heavy,sub-machine guns(SMGs), rifles, andgrenades. All guns have different properties and all grenade types have different in-game effects. Thehand grenade(HE) deals damage in a small radius, thesmoke grenadetemporarily places asmoke screen, the decoy grenade emulates the player's primary gun, theflashbangtemporarily blinds players who look towards it when it explodes, and theMolotov cocktailandIncendiary Grenadeset a small part of the map on fire for a short period of time.Alongside all of the main weapons, the Zeus x27, ataser, can also be purchased(Counter-Strike: Global Offensive).

Global Offensivehas nine main game modes: Competitive, Casual, Deathmatch, Arms Race, Demolition, Wingman, Flying Scoutsman, Danger Zone, and Weapons Course.

Competitive mode pits players against each other in two teams of five players in roughly 45-minute matches.

The Casual and Deathmatch modes are less serious than Competitive mode and do not registerfriendly fireor collision with other teammates. Both are primarily used for practicing.

Arms Race consists of players racing to upgrade their guns via killing enemies.
Demolition is also like the "Gun Game" mod like in the series, though players are also able to plant and defuse the bomb. Players only receive gun upgrades at the start of new rounds if they killed an enemy the previous round.

Wingman is a two-on-two bomb defusal game-mode taking place over fifteen rounds. It is similar to Competitive in the sense that players are paired based on their skill levels.

Flying Scoutsman is a mode in which players are equipped only with a SSG 08 and a knife while they play in low-gravity.

The Flying Scoutsman, Demolition, and Arms Race game modes are placed in the War Games tab.
Danger Zone is a battle-royale mode in which players play against up to 16 or 18 others. Everyone starts with a knife and a tablet and have to search for weapons, ammunition, equipment, and money. Through the tablet, players can purchase certain weapons, ammunition, and equipment with money found around the map inside buildings and in completing objectives such as returning hostages to the rescue zones. When a player purchases an item, it is delivered to them from a drone that goes to their location and drops the item. The tablet is also used for tracking other players.The last person or team alive wins, like other battle-royale games.

The Weapons Course is an offline practice mode designed to help new players learn how to use guns and grenades, as well as defusing and planting the bomb.

Apart from the Weapons Course, all seven other game modes can be played online or offline with bots.