Watch Dogs is an action-adventure game, played from a third-person view. The player controls hacker Aiden Pearce, who uses his smartphone to control trains and traffic lights, infiltrate security systems, jam cellphones, access pedestrians' private information, and empty their bank accounts.[3][4][5][6] System hacking involves the solving of puzzles.[6] The game is set in a fictionalized version of Chicago ("Windy City"),[4] an open world environment which permits free-roaming.[7] It has a day-night cycle and dynamic weather system, which changes the behavior of non-player characters (NPCs).[8] For melee combat, Aiden has an extensible truncheon; other combat uses handguns, shotguns, sniper rifles, machine guns, and grenade launchers.[6][9][10][11] There is a slow motion option for gunplay,[12] and the player can use proximity IEDs, grenades, and electronic lures.[6][9] Lethal and non-lethal mission approaches can be enacted.[13]
Aiden can scale vertical surfaces, hack forklifts and aerial work platforms to reach places otherwise unreachable,[14] and can crouch behind walls to hide from enemies.[15] The player has an array of vehicles with which to navigate the setting, including motorcycles, muscle cars, off-road vehicles, SUVs, luxury vehicles, sports cars, and speedboats.[8][9] The car radio is customizable, with about fifty songs.[16] If the player steals a car, its driver can summon the police;[9] if the player has a good reputation, the driver may acquiesce. A good reputation may be gained by detecting (and stopping) crimes, and a bad reputation results from committing crimes.[17][18] The skill tree is upgraded with points earned from hacking, combat, driving, and crafted items.[19] Money can be used to purchase guns, outfits, and vehicles.[6][9] There are several minigames, ranging from killing aliens to controlling a large, robotic spider.[6][9][16] QR codes and audio logs are included as collectibles;[9][16] ctOS towers unlock map icons and side missions.[6] Multiplayer mode can host up to seven other free-roaming players,[20] with whom the player may complete hacking contracts and engage in races. The player can also be hacked by others, who will perceive the target as an NPC (leaving the target to find the perpetrator). In-game invasions can be disabled, but this will reset the multiplayer skill rank to zero.[6][16][21] Free-roaming with multiple players and decryption mode, where two teams of four are tasked with acquiring and holding data, were excluded from the Xbox 360 and PlayStation 3 versions.