Crackdown is a 2007 action-adventure game developed by Realtime Worlds and published by Microsoft Game Studios for the Xbox 360. Crackdown was conceived by Realtime Worlds founder, David Jones, who also created Grand Theft Auto and Lemmings.

Set in the fictional Pacific City, the player controls a biologically enhanced Agent, tasked with defeating three crime lords and their organized crime syndicates. The Agent's abilities improve by defeating both crime lords and their top subordinates, as well as by completing optional activities, such as street races and scavenger hunts. The gameplay is nonlinear: instead of following a rigid mission sequence, players are free to select the approach to completing their missions and activities. The game features a two-player cooperative play mode via Xbox Live. It was released worldwide in February 2007.

Crackdown, initially planned for release on the original Xbox console, was envisioned as a vast world in which players could experiment and explore freely. Microsoft Game Studios bundled specifically marked copies of Crackdown with an access code to the multiplayer test version of the much-anticipated Halo 3 Beta. The game sold 1.5 million copies in its first six months of release. It received critical acclaim from reviewers and is widely considered to be the best entry in the series. It has garnered several awards for its innovative gameplay. A sequel, Crackdown 2, was released in July 2010 by Ruffian Games without Jones' input, and Crackdown 3 was released for the Xbox One and Microsoft Windows in February 2019, initially to be again directed by Jones before he left to join Epic Games.

Gameplay Crackdown is a third-person shooter set in a sandbox environment, akin to Mercenaries: Playground of Destruction. After selecting one of the predefined Agent characters, the player is assigned to defeat the Kingpin of each gang, though there is no precise approach to do this, leaving players to select their preferred method. While the player may face the Kingpin and his bodyguards at any time, they can improve their chances of taking out the Kingpin by facing and defeating the various Generals responsible for certain aspects of the Kingpin's offense and defense, removing them from play. For example, by eliminating a gang's weapon dealer, gang members will no longer be as heavily armed or will fire fewer shots to conserve ammunition; assassinating the gang recruitment officer similarly reduces the size of the Kingpin's protective force. It is at the player's discretion whether to kill the Generals or skip them entirely before facing the Kingpin. However, the gangs cannot be completely eradicated from the city without tracking down and killing all Generals and Kingpins.

Much like other sandbox games, the player uses melee attacks, guns, and explosives to fight the opposing forces, and can run, climb buildings, jump across rooftops, or use vehicles to navigate the city. Crackdown features a series of character-based skills that can be upgraded to increase specific traits that can be used in combat, driving, or on-foot agility. These skills include: "Agility", which increases the Agent's ability to jump, run, and swim; "Driving", affecting how well he can handle a vehicle and upgrades it; "Explosives", which affects the power and range of explosive weapons and explosive power; "Strength" that increases the Agent's strength, namely by increasing his ability to lift and throw, as well as how hard he can strike an opponent and increases health; and "Firearms", which improves the character's aptitude with weapons. Crackdowns skills make few concessions to realism: character abilities are similar to those of comic book superheroes or cartoon characters. This concept is further highlighted by the ink-like outlines drawn around in-game characters.

Skills are usually improved by gaining experience orbs, which are released from defeated enemies. The type of orb released varies, depending on how the player dispatched the foe; for instance, killing an enemy with a gun will earn Firearms orbs, while running them over with a vehicle earns Driving orbs. More powerful enemies release more experience orbs. However, Agility orbs are awarded differently: they can be earned by either climbing buildings and seeking them on rooftops, or by killing an enemy from a high altitude. The player can also compete in "rooftop races", a race through a series of waypoints across the rooftops of Pacific City, or car races to gain Agility and Driving orbs, respectively. A few special orbs, well-hidden, increase all character abilities when found. A final way to collect orbs is by earning achievements, which rewards the player with orbs from every skill category. Each skill has five levels—beginning with zero stars, and ending with four—with a numeric gauge on the display to indicate how close the player is to the next level. Should the character die, or injure civilians or Agency peacekeepers, their experience gain will be slowed, making it temporarily harder to improve the character's traits.

The entirety of Pacific City may be explored from the start of the game, allowing the player to locate the hideouts of each General and Kingpin, which can be made easier by accessing supply points scattered around the city. Once a supply point is unlocked, the player has the option of returning there to travel to any other supply point, restock on weapons and ammunition, or drop off newly acquired weapons, to permanently add them to their weapon selection. Should the player die, they can respawn at any open supply point. While exploring, the player is likely to come across enemy resistance, with their aggressiveness based on how badly the player has damaged that particular gang recently. If the player is too aggressive against the non-gang residents of Pacific City, including the Peacekeepers, they are flagged as rogue, and Agency hit squads are dispatched to take them down.

Crackdown features an online two-player cooperative play mode that allows drop-in play. Both players may explore the city freely, with the other player's position noted on the HUD map. Players can fight alongside each other, and also inflict friendly-fire damage. The state of the city, including which Generals and Kingpins remain, is determined by the host player's progress. Both players are credited with the defeat of a General or Kingpin in the game—which will affect the state of the guest's progress—but are required to obtain supply points and gain experience independently. Co-op players can race against each other in both rooftop and road races, should they both choose to participate.

Plot Crackdown takes place in the fictional metropolis of Pacific City, whose three districts are divided among eight total islands. The city is controlled by three criminal organizations: Los Muertos (which means "The Dead" in Spanish), a street gang of drug dealers from Central America who runs "La Mugre" ("The Dirt"); The Volk (Russian for "The Wolf"), a militia group from Eastern Europe who dominates "The Den"; and the Shai-Gen Corporation, a formerly above-board, corrupt governing body from East Asia that rules "The Corridor". Normally, a police organization called the Peacekeepers kept the city under control; their forces, however, were overwhelmed by the sudden rise in crime. The city, therefore, sought additional help from "the Agency", an organization that, in addition to outfitting and supporting Peacekeepers, has used advanced surgical and cybernetic technology to create supersoldiers known as "Agents". The Agency is based out of a former resort hotel on an island in the very centre of the city. The player takes on the role of one of their Agents, and is tasked with systematically bringing down all three organized gangs, while keeping both the populace and Peacekeepers safe. The Agent's actions are continuously monitored by the Agency, and its Director (voiced by Michael McConnohie) provides continuous reports to him of his progress.

Throughout the game, the player roams Pacific City, systematically eliminating the leaders of the three gangs. Upon defeating the gangs' Kingpins and generals, the Agent must put down a final riot by the remaining gang members in the area which after completion will cause that district to be almost crime free. Once all three gangs are fully exterminated, in the closing cutscene of the game, the Director reveals to the Agent that there was an ulterior motive for the Agency's actions: the Agency had secretly empowered the three gangs in the first place to instill fear in Pacific City's residents, thus creating a need for the Agency to control the city, and acceptance in the populace when they did take over. The Agency Director's comments suggest that the Agency was merely using Pacific City as a test and will replicate this plan in other cities across the globe to create a New World Order.

Development Crackdown was envisioned to exceed the gameplay of Grand Theft Auto, giving the player "toys" to create their own in-game moments that could be verbally shared with others. The Crackdown logo is in the shape of the Agency Tower, modified. The entire playfield was to be open at the start, requiring the need to create a progression for the player, while still allowing for experimentation. Realtime Worlds had hired a number of former Grand Theft Auto developers who experimented with refining the game's sandbox element. "It was a big part of the idea to just let people do things", Realtime Worlds producer Phil Wilson said about the gameplay; "testers would do things we were completely blown away by". Dave Jones, CEO of Realtime Worlds, described the concept of the game as "How do we reward somebody for just having fun?" They had initially planned to have 200 Xbox Live Achievements for the game towards this purpose, exceeded the then-current cap of 50 set by Microsoft, and pressured Microsoft to lift the cap. Microsoft subsequently increased the maximum number of Achievements in a game to 80. Through playtesting, the team noticed that many players performed certain out-of-the-way actions, such as climbing to the top of the Agency Tower. They created in-game content to reward the player for performing these actions; for example, they created a special rendering procedure for the clouds during the in-game day/night cycle. The renderer would behave differently each day, and could only be viewed from atop the Agency Tower. An initial fear of Jones' was that in the early part of the game, when the Agent is underpowered, the player may not realize the potential of the game and would not complete it; "People weren't quite sure, because at that level, you're kind of like most characters in most other games". Jones also expressed concern that "This game does not look good in screenshots". They took two major steps to overcome this. First, the demo for the game on Xbox Marketplace allowed for accelerated growth of the player's abilities. Second, the full game included five in-game movies that would be presented early on to the player that would give them a taste of what a fully powered character could do.

Wilson stated that development of the game began in 2002 with a target release in 2005 on the original Xbox. Nine people were involved in the initial development for twelve months with plans to expand to 35 during full development. By February 2004, they were able to provide a playable demo, but recognized there were still several challenges with the game's progression. For example, the team introduced "skills for kills" where skill points were only rewarded for killing foes instead of allowing the player to gain them by less risky opportunities. They also included the frequent reporting of the player's current chance of success for a player of defeating a Kingpin to prevent the player from being frustrated by trying to fight Kingpins beyond their level.