Gears of War 3 is a third-person shooter video game developed by Epic Games and published by Microsoft Studios for the Xbox 360. It is the third installment of the Gears of War series, and final game in the original trilogy. Originally due for release on April 8, 2011, the game was delayed and eventually released on September 20, 2011. The story was written by science fiction author Karen Traviss.
 Like its predecessors, Gears of War 3 received widespread critical acclaim from critics. Critics praised its story, voice acting, visuals, and music, but criticized its lack of innovation. Gears of War 3 sold over 3 million copies and was the second best selling game in the U.S.
 A sequel titled Gears of War 4, not developed by Epic Games, was released in 2016.
 Like its predecessors, Gears of War 3 is a third-person shooter that emphasizes the use of cover and squad tactics in order to survive combat situations. The player's character can carry four weapons: one pistol, one set of grenades, and two primary weapons. Firearms can be swapped with other weapons dropped by fallen foes or at stockpiles throughout the game, along with ammunition. When the player reloads a weapons ammunition, they have an opportunity for an "active reload", shown by a small cursor moving over a line with a marked section on the player's heads-up display (HUD). If the player hits a control button when the cursor is in the marked section, they will reload faster with the resulting reload being slightly more powerful than normal bullets, causing more damage to opponents as well as allowing for more "knockback" meaning that enemies running directly at you will be slowed on shot. If they press the button outside this section, this temporarily jams the weapon, leaving the player vulnerable and taking longer to reload. Alternatively, the player can opt to not try for the active reload, reloading the weapon at normal speed, but with no added damage.
 When in combat, the player can take some damage from enemy fire, filling a blood-colored "crimson omen" on the HUD as a measure of the player's health, unlike the traditional health bar in other shooters. By staying out of the line of fire, this will dissipate over time, but by taking too much damage, the player will become downed or killed, and must be "revived" by an ally within a short "bleed-out" period, or else the player will die, unless playing the game on Insane difficulty in which case a player will die immediately after taking too much damage without the bleed-out. The player can also be killed during the bleed-out by the use of the game's signature execution moves by the enemy. Some types of damage, such as explosives or head shots, can kill the player immediately without the bleed-out period. Similarly, the player can also cause enemies to fall into bleed-out in the same manner. The player and their allies and enemies can use nearly any structure as cover, firing blind from behind it or leaning out to take aimed shots while usually exposing their head more. Players can quickly switch between nearby covering walls or jump over lower cover to rush forward.  Within Gears of War 3, some cover can be destroyed after taking some amount of damage, which can be used to a tactical advantage to draw out enemies from cover.
 New to Gears of War 3 is the ability to tag enemy opponents; computer-controlled allies will then concentrate fire on these marked enemies, while human allies will be alerted to their location on their HUD. Players can now also swap weapons and ammunition (and money during Horde Mode) with other allies in the course of battle.
 The player maintains an experience level that persists across all game modes. The player earns experience through kills, performing special types of kills and executions, reviving and aiding teammates, and through general process of the campaign or competitive modes. Players can also gain experience points by winning medals and ribbons, which are awarded for defeating enemies with certain weapons or winning several matches. Earning levels unlocks the use of special characters and weapon skins within the game's multiplayer mode.
 Gears of War 3 takes place two years after Jacinto, humanity's last stronghold, is destroyed in an effort to completely eradicate the Locust Horde. The Coalition of Ordered Governments (COG) remnants relocate to Vectes, a secluded island, in order to rebuild their civilization. The COG then disbands after Chairman Prescott mysteriously disappears and seemingly abandons his forces. A new foe, the Lambent, are threatening humanity's dwindling numbers. As the Lambent begin to invade Vectes, Marcus Fenix and his comrades retreat to the CNV Sovereign, a helicopter carrier, and take refuge at sea, whilst Hoffman leads other survivors back to the mainland to find haven at Anvil Gate. Delta Squad now consists of Marcus Fenix, Dominic 'Dom' Santiago, Anya Stroud, Damon Baird, Augustus 'Cole Train' Cole, Jace Stratton, Clayton Carmine and Samantha 'Sam' Byrne.
 Gears of War 3 begins as Chairman Prescott unexpectedly arrives on the Sovereign. Prescott informs Marcus Fenix he needs to relay important information to the ship's senior officer, Captain Michaelson. The Lambent then launch a surprise attack on the ship, which leaves Michaelson dead and Prescott mortally wounded. Before dying, Prescott gives Marcus an encryption to the disc that Colonel Hoffman has and reveals that his father, Adam Fenix, is still alive but captive on Azura, a secret COG base. Marcus, Dom, Cole, and Baird fight their way to the Anvil Gate Fortress, where Hoffman possesses the necessary equipment to decrypt Prescott's disc. Upon arriving at Anvil Gate, Marcus and his comrades assist Hoffman's soldiers in repelling a combined Lambent and Locust assault.
 Upon further analysis of the disc's content, Marcus learns that Azura is protected by man-made hurricane generators, making the island only accessible by submarine. Marcus and his comrades, joined by old friend Dizzy Wallin, successfully find a submarine but require Imulsion to fuel it. Dom suggests they first venture to an abandoned town called Mercy, where they discover that humans are becoming Lambent. During extraction, the Gears are nearly overrun by Locust and Lambent; Dom sacrifices himself to create an explosion that wipes out the hostile forces. Demoralized, they are forced to continue their search for fuel in the city of Char after their truck runs out of fuel. The ruined city is inhabited by several Stranded civilians who are led by Griffin (voiced by Ice-T). Despite his dislike for the COG and Gears, Griffin reluctantly tasks Marcus to recover a supply of Imulsion. After acquiring the fuel they are attacked by the Locust Horde, led by Queen Myrrah. Griffin's forces sustain heavy casualties in the ensuing battle, but the Gears are ultimately able to escape and reach the shipyards where they have to fight the Locust as they repair and fuel their submarine.
 Marcus' group finally arrives at Azura, discovering that it is a sanctuary and resort for Sera's most elite and powerful individuals. Adam contacts the Gears and reveals he is being held captive atop Azura's main hotel tower. Marcus's group battles through waves of hostiles before finding his father. Adam quickly explains that he has created a device capable of eradicating all Lambent and Locust life forms on Sera. Adam had worked with Myrrah before to try to tune the wave so that only Lambent would be affected, but with the Imulsion, revealed to be a parasitic lifeform, now infecting humans, Adam ran out of time, infuriating Myrrah. Marcus and his comrades defend Adam from the Locust and Lambent, and from an attack by Myrrah. Adam reveals that he had to infect himself with Lambent cells in order to test his machine. As the machine begins to pulsate with energy, Adam bids his son farewell before the device kills him. Myrrah rises from the rubble and begins insulting Adam. Marcus fatally stabs Myrrah with Dom's commando knife he got back in Mercy. Shortly afterwards, the machine emits a blue wave of energy that sweeps across Sera, destroying the Locust, Lambent, and the Imulsion. The scene transitions back to Marcus, who is mournfully wondering what humanity has left. He is comforted by Anya, who assures Marcus that the sacrifices of Adam, Dom, and their comrades have guaranteed humanity a future.
 A DLC acting as a secondary single player campaign to Gears of War 3, the player takes control of both General RAAM, the Locust's main General, and Michael Barrick of Zeta-Six from the Gears of War comic series set during the Evacuation of Ilima several years before the first Gears of War game. Other major characters include Lieutenant Minh Young Kim from Gears of War, Tai Kailso from Gears of War 2, new character Alicia Valera and Jace Stratton from the comics and Gears of War 3. The main setting, the COG city of Ilima, previously briefly appeared in Gears of War 2 as ruins.
 The surviving COG city of Ilima is besieged by a coming Kryllstorm, a mass of millions of Kryll that will devour everything in their path once the city is dark enough. To speed up the Kryllstorm, Locust General RAAM leads an elite unit throughout Ilima, decimating COG resistance and summoning Seeders to black out the sky faster. Throughout the battle, RAAM is instructed by Queen Myrrah who sees taking Ilima as a stepping stone towards reaching the COG capital city of Ephyra.
 At the same time, Zeta-Six is assigned to help evacuate Ilima via convoys of APCs, only to have their checkpoint attacked by massive Locust forces. Repelling multiple waves, Zeta ultimately uses the Hammer of Dawn to finish off the attacking Locust and is reassigned to help another squad defending a bank with civilian survivors inside. Zeta fails to save the other Gears and most of the civilians, but discovers a young Jace Stratton holed up inside of the bank's vault. The squad rescues Jace and escorts him to a convoy for evacuation, killing several Seeders and a Brumak to protect the convoy. At Jace's request, Zeta agrees to check out the local high school where Jace believes that there might be more survivors, including his adoptive father Dr. Wisen.
 Reaching the high school, Zeta finds it to be a COG evacuation center which has been overrun by the Locust, including a Berserker, packs of Wretches and several giant Serapedes. However, they overhear a message from Dr. Wisen directing the survivors of the attack on the school to retreat to his nearby orphanage. Zeta fights their way back outside, managing to kill the Berserker by using several exploding cars in the parking lot. Finding their comms blocked by the Seeders and with time running out, Zeta fights their way to city hall where Barrick uses the mobile command center located there to take control of the Hammer of Dawn and kill the Seeders. With communications restored and less than half an hour left until the city is consumed, Zeta contacts Command who reveals that they are the only COG forces left in the city. As Kim refuses to abandon the survivors at the orphanage, Command agrees to redirect the last APC to meet them there for evacuation.
 At the orphanage, Zeta discovers several survivors, including Dr. Wisen. As the APC arrives, carrying Jace, General RAAM leads a personal attack on the survivors, killing Alicia Valera and destroying the APC. Jace joins the remaining Gears in fighting off the Locust, though they are quickly cut off from the others. Zeta and Jace fight their way back through the nearby streets and sewers, encountering and killing most of RAAM's elite unit, particularly the elite Theron Guard that had been acting as RAAM's second in command during the battle. Upon their return to the orphanage, the Gears and Jace face off against multiple waves of Locust led by RAAM himself from atop a Reaver and weaponizing the Kryll against them. The group manages to shoot down the Locust General's Reaver, but Barrick is forced to stop the vengeful Kim from making a suicidal attack on the trapped and injured RAAM. Retreating to the roof, the survivors are evacuated by a King Raven helicopter just before the Kryllstorm completely engulfs Ilima. Impressed with Jace, Barrick commends the young man's courage and states that he will make a great Gear in the future.
 Gears of War 3 includes a stereoscopic mode for 3DTV sets. It uses TriOviz for Games Technology, which is integrated with Unreal Engine 3, for stereoscopic 3D support. All Gears of War 3 gameplay and cinematics have S3D support, and this extends to split-screen play as well.
 On December 17, 2010, Epic Games confirmed that the Epic Edition of Bulletstorm for the Xbox 360 included early access to the multiplayer beta of Gears of War 3 and access to exclusive content. It was later announced that pre-ordering Gears of War 3 in any edition at GameStop in the United States or GAME in the United Kingdom would grant access to the public beta. The Gears of War 3 exclusive beta began on April 18, 2011, a week before the GameStop pre-order beta which began on April 25, 2011. There was in-game content unlockable exclusively for beta testers that included characters and weapon skins. All players that participated in the beta received a medal to identify themselves as beta testers upon the release of the final game. The beta concluded on May 15, 2011.
 In 2017 and later in 2020, footage of Gears of War 3 running on a PlayStation 3 surfaced. The footage was confirmed to be legitimate and appeared to be from a data breach Epic had suffered in 2011, but Kotaku confirmed with Epic Games that the source of the footage was not  from an unannounced port of the game to the PlayStation 3, but was from a test of the Unreal Engine. Epic called the software "a byproduct of Epic’s internal Unreal Engine 3 testing process, which utilized both Gears and Unreal Tournament, and was never part of any actual product work for PlayStation 3."
 According to Tim Sweeney, Gears of War 3 cost between $48,000,000 and $60,000,000 to develop. The game was officially unveiled on Late Night with Jimmy Fallon by Cliff Bleszinski, with a teaser trailer featuring the song "Heron Blue" by Sun Kil Moon. Prior to the official reveal, an advert for the game was accidentally displayed on the Xbox 360 Dashboard.
 The game was available for pre-order in three retail versions: Standard, Limited, and Epic. The game also has special character variants based on where the game was pre-ordered. Confirmed variants include Mechanic Baird, Commando Dom, Savage Grenadier Elite, and Savage Kantus. On May 23, 2011, Epic Games confirmed that an exclusive replica Retro Lancer designed by NECA will be available exclusively at GameStop, while a gold version of the replica Retro Lancer is also available exclusively at Play.com.
 Clayton Carmine, brother of Anthony and Benjamin, of the previous two games, appears in Gears of War 3. Carmine is more competent, witty, and muscular in the third game, with tattoos of his brothers and the reasons they died on his arms (Keep your head down! and Practice reloading!). He was shown wielding a Mulcher machine gun in several released pictures from the game. A vote was held between July 29, 2010, and September 6, 2010, to determine whether Carmine would live or die based on sales of Xbox avatar T-shirts available for purchase on Xbox Live; Epic had developed endings reflecting either choice prior to the conclusion of the vote. Additionally, actual T-shirts were available from San Diego Comic-Con with all purchases. The voting campaign raised over $150,000, which was all donated to Child's Play.
 Ice-T voices the character of Griffin. It was announced during E3 2011 that Ice-T's band, Body Count, would be reuniting to make a song titled "The Gears of War", which was featured in the Horde 2.0 trailer.
 Announced via Twitter from Cliff Bleszinski, Gears of War 3 will have unlockables just like Gears of War 2.
 At the San Diego Comic-Con International Convention, Paul Jr. Designs aka "PJD", the company of Paul Teutul Jr. from the Discovery series American Chopper, revealed their commissioned Gears of War trike. Discovery episodes chronicled their efforts to build the trike, visits to Epic and them interpreting various merchandising and promotional material into the bike. The team from Epic was impressed and even mentioned the possibility of adding the trike to a future game in the series.
 On 29 August 2011, Microsoft and Epic Games announced a Gears of War 3 Season Pass that entitles gamers to the first four installments of downloadable content (at a discount) that will roll out over the course of the next year, with the first releasing in November 2011. Previous characters in the series, including Tai and RAAM, will be future downloadable content characters. It has also been confirmed that Story DLC will be available after launch, and that the regular cast of Gears of War will not be in future DLC.
 The first downloadable content is the "Horde Command Pack", which was released on November 1, 2011. In addition to new character and weapon skins, it provides three new maps for use in Versus and Horde mode and three new fortifications that the players can build.
 The second downloadable content is called "Versus Booster Map Pack". It was released on November 24, 2011, and is available for free. The pack contains five multiplayer maps which includes Blood Drive, Azura, and Rustlung, which were originally made available through the Horde Command Pack; and Bullet Marsh and Clocktower, which will be new to Gears of War 3.
 The third downloadable content is "RAAM's Shadow". The expansion was released on December 13, 2011.
It includes four new multiplayer characters, a new weapon set named "Chocolate", new achievements, and over 3 hours of singleplayer gameplay. The story takes place before the first Gears of War, set in Sera post-emergence day. Zeta Squad is enlisted to evacuate Ilima City and protect the citizens against a Locust Kryll storm. The player will be in the role of General RAAM, the main antagonist from the first Gears of War. Zeta is led by Michael Barrick (from "Gears of War" comics fame) and composed of returning characters such as Lt. Minh Young Kim, from the first Gears of War and Tai Kaliso from Gears of War 2, Jace Stratton from Gears of War 3 and also includes a new female character, Alicia Valera. The primary setting is the city of Illima from Gears of War 2.
 The fourth downloadable content is entitled: "Fenix Rising", and it was released on January 17, 2012. The DLC includes five new multiplayer maps and also introduced four new character skins and a new system that allows players to rank up through level 100 multiple times.
 The fifth and final downloadable content, entitled "Forces of Nature" was released on March 27, 2012. The map pack is based around weather and natural disasters and consists of three new multiplayer maps (Aftermath, Artillery, and Cove), as well as remade versions of Jacinto and Raven Down. On top of the new maps, the DLC also includes four new character models, five weapon skins ready to use immediately, and two unlockable weapon skins. New Easter-egg type weapons, Elemental Cleavers, are introduced.
 Upon release, Gears of War 3 received critical acclaim, garnering an aggregate score of 91.49% on GameRankings and 91/100 on Metacritic. Jeff Gerstmann of Giant Bomb gave Gears of War 3 a review of 5 out of 5 stars; stating "Gears of War 3 is a fantastic follow-up that answers important questions about the nature of the Gears universe while backing it all up with an even bigger, better multiplayer suite." IGN called it "the spectacular conclusion to one of the most memorable and celebrated sagas in video games." Game Informer gave it a 9.5/10, saying that "Gears 3 is a fantastic idea polished to near perfection by an enormous crew of talented developers and a bottomless budget," with "a constantly shuffling deck of threats that encourage players to experiment with new weapons and tactics," "hilariously over-the-top set piece moments," and a "smart approach to network play."
 After Eurogamer published an 8/10 review for the game, Epic Games' Cliff Bleszinski reported, saying "When people rated [Gears of War 2] higher than [Gears of War 3], it kind of upset me because I know [Gears of 3] is a better game on every level."  His comments were criticized by Destructoid and GamePro. In GamePro, McKinley Noble argued that "slamming a 'bad' review that's actually pretty favorable does come off as selfish".
 Gears of War 3 received more than one million pre-orders. The game sold more than 3 million copies during its first week—higher than the previous two Gears of War entries. It was the second-best selling game only behind Madden NFL 12.
 During the 15th Annual Interactive Achievement Awards, the Academy of Interactive Arts & Sciences nominated Gears of War 3 for "Action Game of the Year" and "Outstanding Achievement in Online Gameplay".