San Andreas is structured similarly to the previous two games in the series. The core gameplay consists of elements of a third-person shooter and a driving game, affording the player a large, open world environment in which to move around. On foot, the player's character is capable of walking, eating, running, sprinting, swimming, climbing (the first GTA game in which swimming and climbing is possible) and jumping as well as using weapons and various forms of hand to hand combat. Players can drive a variety of vehicles, including automobiles, buses, semis, boats, airplanes, helicopters, trains, tanks, motorcycles and bikes. Players may also import vehicles rather than steal them.
The open, non-linear environment allows players to explore and choose how they wish to play the game. Although storyline missions are necessary to progress through the game and unlock certain cities and content, they are not required as players can complete them at their own leisure. When not taking on a storyline mission, players can free-roam and look around the cities, eat from the restaurant, or cause havoc by attacking people and causing destruction. However, creating havoc can attract unwanted and potentially fatal attention from the authorities. The more chaos caused, the stronger the response: police will handle "minor" infractions (attacking people, pointing guns at people, stealing cars, killing a few people, etc.), whereas SWAT teams, the FBI, and the military respond to higher wanted levels.
The player can also partake in a variety of optional side missions that can also boost their character's attributes or provide another source of income. The traditional side missions of the past games are included, such as dropping off taxi cab passengers, putting out fires, driving injured people to the hospital and fighting crime as a vigilante. New additions include burglary missions, pimping missions, truck and train driving missions requiring players to make deliveries on time, and driving/flying/boating/biking schools, which help players learn skills and techniques to use in their corresponding vehicles.
Not all locations are open to the player at the start of the game. Some locales, such as pay 'n spray, gyms, and shops, become available only after completing certain missions. Likewise, for the first portion of the game, only Los Santos and its immediate suburbs are available for exploration; unlocking the other cities and rural areas again requires the completion of certain missions. That said, it's possible - given the player's ability to swim which has been added - to enter the other areas ahead of time, although doing so results in the player being immediately attacked by law enforcement. The use of certain cheat codes, however, can remove this obstacle and allow the player to free-roam virtually the entire state at will.
Unlike Vice City and GTA III, which needed loading screens when traveling between different districts of the city, San Andreas has no load times when the player is in transit (which is notable, given how much larger the in-game map is than in the previous games). The only loading screens in the game are for cut-scenes and interiors. Other differences between San Andreas and its predecessors include the switch from single-player to multiplayer Rampage missions (albeit not in the PC version), and the replacement of the 'hidden packages' with spray paint tags, hidden camera shots, horseshoes, and oysters to discover.
The camera, fighting, and targeting controls were reworked to incorporate concepts from another Rockstar game, Manhunt, including various stealth elements,[19] as well as improved target crosshairs and a target health indicator which changes colors from green to red to black depending on the target's health. The PC version of the game implements mouse chording; the player has to hold the right mouse button to activate the crosshairs, and then click or hold at the left mouse button to shoot or use an item, such as a camera.
