Call of Duty: Modern Warfare 3 is a 2011 first-person shooter game developed by Infinity Ward and Sledgehammer Games and published by Activision. The game was released worldwide on November 8, 2011, for Microsoft Windows, the Xbox 360, PlayStation 3, Wii, and OS X. It is the sequel to Call of Duty: Modern Warfare 2 (2009), serving as the third and final installment in the original Modern Warfare trilogy and the eighth Call of Duty installment overall. A separate version for the Nintendo DS was developed by n-Space, while Treyarch developed the game's Wii port. In Japan, Square Enix published the game with a separate subtitled and dubbed version.

The game's campaign follows Modern Warfare 2 and begins right after the events of its final mission. Similar to Modern Warfare 2, it is centered on Task Force 141, which contains Captain Price, Soap MacTavish, and a newly introduced playable character, Yuri. Alongside the Delta Force and Special Air Service, they hunt Vladimir Makarov (the main antagonist of the trilogy), a Russian terrorist who leads the Russian Ultranationalist party. He led several terror attacks across Europe, triggering a large-scale war between the Ultranationalists and friendly forces. For the game's multiplayer mode, new mode types and killstreak choices were brought in. Improvements were also made to the mode that solved issues that appeared in Modern Warfare 2.

Using an enhanced version of Modern Warfare 2s IW engine, development for the game began in 2010 with more than one developer studio. Prior to development, Infinity Ward co-founders Jason West and Vince Zampella left the company to form Respawn Entertainment. Other members had been fired or had left the company following the duo's departure. Sledgehammer Games had joined the Modern Warfare 3 development force, with Raven Software also developing the game's multiplayer mode. Following a large leak containing detailed information about the game, multiple teaser trailers were released, with each showcasing a location featured in the game's campaign, leading up to a full reveal.

Modern Warfare 3 received positive reviews from critics, with praise for its gameplay, campaign, and multiplayer, although there was some criticism for its story and lack of innovation. Retrospective reviewers believe the game failed to match the standards set by its two predecessors. It won the award for Best Shooter at the 2011 Spike Video Game Awards, as well as Action Game of the Year at the 15th Annual Interactive Achievement Awards. It was a massive commercial success. Within 24 hours of going on sale, the game sold 6.5 million copies in the United States and the United Kingdom and grossed $400 million, contemporaneously making it the largest entertainment launch ever.

Gameplay Modern Warfare 3 is a first-person shooter video game much like its predecessors. Modern Warfare 3 for Microsoft Windows has dedicated server support.

Campaign The player assumes the role of various characters during the single-player campaign, changing perspectives throughout the progression of the story, which, like its predecessors, is divided into three sets of missions called "Acts". Each mission in an act features a series of objectives that are displayed on the heads up display, which marks the direction and distance between such objectives and the player. Damage to the player is shown by the visualization of blood-spatter or red-outs on the screen. The player's health regenerates over time as long as the player character avoids taking damage for a limited time. Mission objectives vary in their requirements, ranging from having the player arrive at a particular checkpoint, to eliminating enemies in a specified location, to standing their ground against enemy squadrons, directing remote-operated weapons, and planting explosive charges on enemy installations. The player is also accompanied by fellow soldiers who cannot be issued orders. Like its predecessor, the game includes an interactive scene of a terror attack against civilians, which the player is given the option of skipping due to the portrayal of graphic and potentially upsetting content, including harm to children.

Cooperative Modern Warfare 3 features a new mode, called Survival. This mode allows between one and two players to fight massive waves of enemies, with each wave becoming increasingly difficult. It differs from the Nazi Zombies mode in Call of Duty: World at War, principally in that enemies no longer spawn at fixed locations as the zombies do, but instead appear at tactical positions based on the current location of the player. The mode is available on all multiplayer maps in the game. Players earn in-game cash for items such as weapons, upgrades, ammo, air/ground support, and equipment if they kill or assist in killing enemies, while more items can be unlocked by earning XP which is also increased by killing enemies. Special Ops also returns from Modern Warfare 2. These challenge missions feature up to 48 stars, unlike its previous installment, which featured 69. Some weapons in Spec Ops are exclusive to that game mode and are not available for play in multiplayer mode.

Multiplayer

The entire Killstreak reward system has been altered to make it more difficult for players to get early unlocks. Killstreaks are now known as Pointstreaks, and kills are no longer the only way to increase the player's point streak. Completing objectives such as planting a bomb or capturing a flag in Capture The Flag awards points towards the player's Pointstreak. Pointstreak rewards are organized into three different "strike packages" called Assault, Support, and Specialist.

The Assault strike package works the same as the Killstreak reward system in Modern Warfare 2 and Black Ops: the player must earn more and more points without dying. Once the player is killed, their points are reset to zero. Likewise, the Specialist strike package rewards players with perks after every second consecutive kill. Upon death, however, the player loses all the perks and the points are reset to zero. In contrast, the Support strike package is awarded based on the total points that the player has earned over the entire match, regardless of how often the player dies. If a player switches to a custom class with a different reward system (either assault or specialist) during gameplay, all points are automatically reset to 0. Players are allowed to choose which Pointstreak rewards they want to use when they gain it during the match, rather than choosing them between rounds.

Along with revamping the entire Killstreak reward system, Modern Warfare 3 also has a completely modified Ranking and Unlocks system, which does not use a currency system for unlocks. The player's primary weapon levels up alongside the player, and unlocks a number of "Proficiency" perks such as Attachments, (allows two attachments and is a successor to the "Bling" and "Warlord" perks), Kick (reduced recoil while aiming down the player's sight) and Focus (reduced flinching while under fire). Only one Proficiency can be put on a primary weapon. Another new addition is the ability to equip "Hybrid Scopes" on a weapon, such as a holographic sight with a red dot magnifier, allowing players to switch between magnified and non-magnified. Modern Warfare 3 introduces a new "Prestige Shop" which will unlock only after the player has selected the option to prestige for the first time. The "Prestige Shop" allows Prestige players to use tokens they gain from using the Prestige option to buy exclusive features such as double XP and an extra custom weapon class. The player is able to Prestige 20 times.

Several controversial perks in Modern Warfare 2, accused of being too overpowered, have been removed in Modern Warfare 3. Diving from standing to prone, known as "dolphin diving", has been removed due to balancing issues. Modern Warfare 3 utilized Treyarch's hot fix system to fix bugs and glitches. Modern Warfare 3 features a local and online split-screen option. (Not available for the Wii version.)

New game modes were added: Kill Confirmed: players must collect floating dog tags from the corpse of a downed enemy before the kill can be registered. However, the opposing team can pick up the dog tag as well to deny the other team a kill, which denies the other team a point. Team Defender: both teams attempt to capture a flag dropped by the first person who is killed when the match starts, the team of the person who holds the flag will get double points for their kills; while the team without the flag only gets the default number per kill. Private matches also now include pre-made game modes including: "Infected" (where the infected kill enemies to recruit them to their team), "Drop Zone" (where the player must hold a drop zone for points and care packages), "Team Juggernaut" (each team plays alongside an AI Juggernaut character), "Gun Game" (be the first to get one kill with every gun in the game), "One in the Chamber" (in which players are only allowed one pistol with one bullet and three lives where they can only get more bullets by killing other players), and "Juggernaut" (free for all against a juggernaut, kill the juggernaut to become it). Along with this, players are allowed to create their own game modes with customized settings such as number of players and time limit.

Special Ops The Special Ops game mode from Modern Warfare 2 is present in Modern Warfare 3, and includes new features which make it more replayable and similar to other game modes, such as Nazi Zombies from previous Call of Duty games, and Hordes from Gears of War. The two main Special Ops modes include one that is generally the same as the last Modern Warfare game, and a new wave-based game, Survival, where the player is inserted into a multiplayer map alone or with a single partner and defends an area against waves of enemies. The players can buy support options unlocked with money earned during each round via the means of killing the enemy and completing the optional objectives on each wave, which vary from getting multi-kills to not taking damage. You gain experience for killing them which allows for more weapons to be unlocked, as well as other support options. The mode also works with the DLC multiplayer maps.

Story Characters The game sees the return of Task Force 141 members Captain John "Soap" MacTavish (Kevin McKidd), Captain John Price (Billy Murray) and Russian loyalist "Nikolai" (Robin Atkin Downes). Task Force 141 was officially disavowed due to Shepherd's death, with the truth of his involvement in igniting World War III known only to Price, Soap, and Nikolai. For most of the game, the player controls Yuri (Tony Curran), an ex-Spetsnaz operator and former associate of Russian Ultranationalist terrorist Makarov, who joins Task Force 141 on their hunt for Makarov, who returns as the game's main antagonist. Several playable characters have been added, including Delta Force operator Staff Sergeant Derek "Frost" Westbrook; Special Air Service Sergeant Marcus Burns; and Andrei Harkov, a Russian FGS agent tasked with protecting the Russian president. Just like President Al-Fulani in the first game, Soap is only "playable" during the game's opening sequence; while Price becomes the player character in the game's final mission, and is the only character in the trilogy who speaks while playable. The player also takes control of an AC-130 TV Operator during the Battle of Paris.

New non-player characters (NPCs) include Delta Force operatives "Sandman" (William Fichtner), "Truck" (Idris Elba), and "Grinch" (Timothy Olyphant), who serve as Frost's squadmates. Captain MacMillan briefly returns from Call of Duty 4: Modern Warfare as "Baseplate" (also Curran). Craig Fairbrass, who originally voiced the characters Gaz and Ghost, reprises his role SAS operative Sergeant Wallcroft, who originally had a minor role in the first Modern Warfare.