Gameplay
Like the previous games in the series, Global Offensive is an objective-based multiplayer first-person shooter. Each player joins either the Terrorist or Counter-Terrorist team and attempts to complete objectives or eliminate the enemy team. The game operates in short rounds that end when all players on one side are dead or a team's objective is completed. For most game modes, once a player dies, they must wait until the round ends to respawn. Players purchase weapons and equipment at the beginning of every round with money awarded based on their performance. Completing objectives or killing enemies earns the player money while negative actions, like killing a teammate or hostage, takes money away from the player. In addition, when a round ends all players receive some amount of money, with players on the winning team receiving substantially more.
Counter Strike Global Offensive adds new weapons and equipment not seen in previous installments, most notably the firebomb for each side (Molotovs for Terrorists and incendiary grenades for Counter-Terrorists). These temporarily cover a small area in fire, dealing damage to anyone passing through.

Game modes
Currently, Global Offensive features five game modes for online play:
Classic Casual and Competitive: Counter-Strike's most well-known game mode, both involving Defuse and Hostage missions.At the start of each round, players can purchase weapons and gear with money earned from various actions, from assisting on kills to completing objectives. For both mission types, a round ends when either a team completes an objective, or eliminates the other team.
Defuse: the Terrorists must plant a C4 explosive at one of two designated bombsites; the Counter-Terrorists must prevent the bomb from exploding.
Hostage: the Counter-Terrorists must rescue hostages from the Terrorists, and bring them to an extraction point; the Terrorists must prevent the hostages from escaping. If a Terrorist or Counter-Terrorist attempts to kill hostage, they will suffer a heavy cash penalty. An update later changed how Counter-Terrorists rescue hostages: instead of leading them around, players must carry one hostage at a time to the extraction point.
Arms Race: a deathmatch-based mode where each player is rewarded for each kill with a new weapon, with the first player to get a kill with every weapon in a predetermined set winning the game.
Demolition: a round-based mode that removes weapon and equipment purchasing, instead rewarding players who manage at least one kill by giving the next weapon in a predetermined set of weapons.
Deathmatch (added on November 12, 2012) a mode consisting of 10-minute matches. Players must gain the highest possible score by earning kills with different weapons or desired weapons. The number of points from a kill depend on the weapon. Players may also take advantage of bonus timers for different weapons, using them to score extra points. Like in Arms Race, players automatically respawn after getting killed, but also when they choose to respawn with bonus weapons.
Global Offensive also offers two offline modes: Offline with Bots, which offers the same game modes with AI-controlled bots; and a Weapons Course for inexperienced and veteran players alike.