Besides driving, one of GTA's core gameplay features is the ability for the player to control the action of their player characters on foot. Originally, on foot action as seen in Grand Theft Auto simply encompassed basic movement and operation of weaponry in GTA, but was significantly improved from Grand Theft Auto III onwards to include additional features and capabilities.
Running, jumping, climbing, etc.
In GTA, the player only possesses the ability to run and jump, the latter allowing the player character to basically "fly" over vehicles, which can be used to hide behind cover of a vehicle or cut corners while running on foot. GTA introduced a comedic feature of "burping" and "farting" that was never reintroduced in any other games besides GTA 2.
For GTA III, the player possesses the ability to walk, run and sprint. Walking is only possible via the use of a game pad's analog control, while sprinting, essentially accelerated running, is executed by the press of a button or key, but is limited in that the player character will go tired after an extended amount of sprinting. Sub-missions allow the player to infinitely sprint, while players may alternatively tap the sprint command instead to maximize the sprint command's effectiveness if they have yet to acquire infinite sprint. For Grand Theft Auto: San Andreas, tapping the sprint command will allow the player character to run faster than holding it. Walking is also made possible as a readily available command to slow down runs in San Andreas, and is the default movement in Grand Theft Auto IV, which in turn requires the player hold the sprint command to run and tap to sprint.
The jump command was further refined in GTA III to allow the player to better jump up vehicles and solid objects in the environment, although that too has its limitations: The player must stand at an optimum distance from the target which they want to jump up to or the player character will instead back up in a "dodging" stance if they are too close to the targeted location. The jump command was complemented with the ability to climb in Grand Theft Auto: San Andreas; by jumping in front of a fence, wall or an environmental object, the player can climb up if they can reach the edge of the object and grab hold. These changes were not adopted in Grand Theft Auto: Liberty City Stories, which used pre-GTA San Andreas player movement, but were utilized to a limited extent in Grand Theft Auto: Vice City Stories to allow the player to climb out of water. For Grand Theft Auto IV, San Andreas' jump-climb abilities were reintroduced and the player character is given the additional ability to shimmy along a straight ledge after jumping and grabbing hold; players are also able to scale ladders (which, until GTA IV, were non-interactive), allowing for access to places that will otherwise require the use of an aircraft. In addition to ladders, fire escapes which were also non-interactive in the GTA III era, were implemented in GTA IV, though many of them require the player to jump onto a vehicle in order to access one by street level rather than the actual use of one by access via roof.
Combat and firearms
Another core aspect while on foot is the ability to wield and use weapons. Whereas the first GTA game began with only five weapons, the series has since expanded selections of weapons to include hand-to-hand combat (including melee weapons), firearms and explosives. Other unconventional items that are classified as "weapons" include cameras, dildos and vibrators, flowers, night vision and thermal vision goggles, fire extinguishers, parachutes and others seemingly non-lethal objects.
Swimming was introduced in Grand Theft Auto: San Andreas to allow the player to travel on water or underwater without the aid of a vehicle. The feature has since enjoyed some use, with Grand Theft Auto: Vice City Stories, IV, Chinatown Wars and V adopting the feature. For games without this ability, contact with deep water can lead to a quick death.
In the 3D Universe games the player can obtain infinite sprint by completing the paramedic side-mission except in San Andreas where it is obtained by collecting $10,000 total in the burglary side-mission.