[[quoteright:221:http://static.tvtropes.org/pmwiki/pub/images/halo-3-001_800.png]]
[[caption-width-right:221:Finish The Fight.]]

->''"They let me pick, did I ever tell you that? Choose whichever Spartan I wanted. You know me. I did my research. Watched as you became the soldier we needed you to be. Like the others, you were strong and swift and brave. A natural leader. But you had something they didn't. Something no one saw... but me. Can you guess? '''[[BornLucky Luck]]'''. Was I wrong?"''
-->-- '''Cortana'''

The final game in the (first) ''Franchise/{{Halo}}'' trilogy. Picking up directly from ''VideoGame/{{Halo 2}}'', Master Chief returns to fight for Earth and discover the secrets of the Halo builders. This game earned $170 million in its ''first day'', breaking all previous records (including ''Halo 2'''s.)

The campaign was no longer split into two parts, instead having a single co-op campaign revolving around the Master Chief and the Arbiter working side by side. The story wrapped up the trilogy and shows the conclusion of the war.

The gameplay was kept largely intact and identical to the previous games, only refining the changes made in ''Halo 2''. The only real new features are the weapon types (a complete subset of Brute weapons and two additional grenade types to the standard frag and plasma, spike and incendiary) and equipment you can deploy that changes the battle dynamics (impenetrable "bubble shield," trip mine, radar jammer, etc.)

After an {{Interquel}} and a {{Prequel}}, ''VideoGame/{{Halo 4}}'' is the next chronological game in the series, showing the aftermath of the war and the continued development of the UNSC and Spartan program.

On October 16 2013, ''Halo 3'' became free-to-play... [[http://www.gamespot.com/news/halo-3-free-on-xbox-live-starting-october-16-6415124 provided the player has an Xbox Live Gold account]].
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!!''Halo 3'' provides examples of:

* ArcWords: "Were it so easy."
* AGodAmI: "My feet tread the path... I shall become a God!"
** The Gravemind apparently had delusions of godhood as well. Though they might not actually be delusions with him.
* AfterTheEnd: This game kicks off just as the Covenant have killed nearly all of humanity, with the Flood not far behind.
* AlienSky: Once you get to ''The Ark'', the sky features an entire ''galaxy''. Go ahead. Take a moment to stare at it.
* BackToBackBadasses: Master Chief and Arbiter pull this near the end of the game.
* BadassBoast:
-->'''Elite''': Brute ships, staggered line! Ship Master! They outnumber us three-to-one!
-->'''R'Tas Vadum''': [[ILikeThoseOdds Then it is an even fight.]]
* BashBrothers: The Chief and Arbiter are paired off with one another in single player and for the entirety of co-op.
* BigDamnHeroes: Twice. First during the [[ZombieApocalypse Flood invasion,]] the second in the finale against [[spoiler: Guilty Spark]]
* BitterSweetEnding: [[spoiler: Truth is killed, the Flood are destroyed on Halo, and the War is over, but Master Chief and Cortana are lost in space at the end of the ''Forward Unto Dawn'' with no way to get home, and the Chief is forced to go into cryogenic stasis to stay alive. And also, Johnson. Miranda Keyes and many more are dead.]]
* BookEnds: "Were it so easy."
** The first time, before the first level begins, it's said by the Arbiter as a response to Sergeant Johnson telling him and the Master Chief not to kill each other. The second time, at the end of the game, it's said [[spoiler: by the Arbiter again, as a response to Lord Hood's statement: "It's hard to believe [the Master Chief] is dead." And I'm not sure which would be worse, the what-if idea that the Chief had died, or the fact that the Chief is still alive, and yet no one back on Earth knows any better.]]
** ''HaloCombatEvolved'' opened with Master Chief being thawed from cryo-sleep. ''Halo 3'' ends with him going back into cryo-sleep.
*** ''HaloCombatEvolved'' had Cortana say "keep your head down! There are two of us in here now, remember?". In Halo 3, once you re-unite, she says to "Remember to keep your head down..."
** They also both end with him riding a Warthog to escape an exploding [[spoiler:Halo. The same Halo in fact]].
* CallBack: Escaping the exploding station in a Warthog.
* CatastrophicCountdown: a variant. After starting up the [[spoiler:Halo Ring]] it needs several minutes to charge and literally shakes itself apart. The last section of the game is a mad dash to find a way off. While there's no explicit timer the structural plates fall off at a constant rate. Justified in that the thing was half-built when it was fired.
* ColossusClimb: This is generally how Scarab fights play out.
* ContinuityNod: Nearly everything Cortana says in her cryptic remarks during the game are near exact quotes of lines in ''TheFallOfReach'', which was the jumping point for the entire ExpandedUniverse.
** [[spoiler: When Truth activates the Halo rings, the fourth of the seven rings (representing the Halos) does not light up. Installation 4 was the one blown up in the first game.]]
* CoOpMultiplayer: Not only was ''Halo 3'' one of the first console games to include online co-op, but it also had a campaign mode where players could earn points from killing enemies and compete against each other to earn the most. Basically, [[MindScrew Competitive Cooperative]] Multiplayer.
** GameplayAndStorySegregation: zigzagged trope. In 1P, the Arbiter is a friendly NPC who is present in almost all levels. In two-player co-op, he's the second player's avatar. In three-or-more player co-op, two more Elites just magically appear out of nowhere, with no particular plot justification, relevance or lines.
*** They actually do have canon personalities (though not anything elaborated on in-game). Basically, one is a hardened veteran who is rather suspicious of humans, and the other is a young rookie who might as well be an otaku for us.
* ChargedAttack: The Spartan Laser takes about 3 seconds to fire, but destroys everything that it touches (and has sniper-grade range) and goes through your units, too (although a tank and scenery can stop it).
** The Plasma Pistol, which can now stun vehicles.
* CyberCyclops: [[NamesToRunAwayFromReallyFast Brute]] [[InvisibleMonsters Stalkers]], the {{Replacement Mooks}} for the Stealth Elites from the first two games, have this look going on. Though you probably wouldn't notice, due to the fact that (a) [[CaptainObvious they're invisible most of the time you fight them]], and (b) [[UniqueEnemy they only appear in two places throughout the entire campaign]]. Bonus points though for the eye itself being [[RedEyesTakeWarning red]].
* DamnYouMuscleMemory: Many people in this game's beta ended blowing themselves up with a mine after attempting to reload their weapons, after being used for so long with pressing X. In more hilarious cases, they deployed mines below ''Warthogs''.
* DeadCharacterWalking: If you're [[http://www.youtube.com/watch?v=aXYt6-2OasM very careful, follow a set of specific actions, have a lot of patience, and a good dose of luck]], it's possible to save [[spoiler: Sergeant Johnson]].
* DifficultButAwesome: The Spike grenades appear to be weaker versions of the plasma grenades, until you learn that their explosive pattern is conical from the place of impact. They're meant to be stuck on walls and around corners you can fill a hallway with deadly spikes that can kill from upwards of 40 feet away.
* DoesThisRemindYouOfAnything: When the Chief finally rescues [[spoiler: Cortana, the Gravemind's MindRape has left lying on the "floor" of the holo-projector looking ashamed and broken. Just like a real rape victim.]]
* EnemyMine: The humans and Separatist Elites [[spoiler: and temporarily the Flood]] against the Covenant Loyalists.
* DarkerAndEdgier: The first two games largely avoided the implications of just how many had died/were dying in the Covenant War, but this game has Earth AfterTheEnd and takes an AnyoneCanDie approach to the main characters.
* DualBoss: The two Scarabs in The Covevant.
* DuelToTheDeath: [[AllThereInTheManual Brute society relishes in the chances to defend their honor in duels to the death]]. In the level "The Ark", a Brute Chieftain challenges [[PlayerCharacter the]] [[SuperSoldier Master]] [[OneManArmy Chief]] to have one with him, with even the formality of having all his Mooks standing in a semi-circle to watch you two fight. Guess who wins.
* EnemyChatter: "You big bully!"
* FanNickname: R'tas Vadum (the Elite counterpart to Lord Hood) is also known by fans as "Half-Jaw," because, well, [[ExactlyWhatItSaysOnTheTin you know]]...
* {{Foreshadowing}}: There are multiple hints towards [[spoiler: the rebuilt first Halo, including Guilty Spark's curious "Oh my!" when first accessing the Ark's computer systems and the control room showing ring 4 as incomplete (but ''not'' utterly destroyed, as it was after ''Halo: CE'').]]
* GunsAreWorthless: on Easy at least, hitting enemies with your gun often seems to do more damage than shooting them.
* HamToHamCombat: A three-way between Truth, Gravemind, and the Arbiter.
* ILikeThoseOdds: See Badass Boast above.
* InfernalRetaliation: When a Brute Chieftain's charging at you, roaring, and brandishing a gravity hammer, you might think of hitting them with a firebomb, as it does a lot of damage. Unfortunately, Chieftains have equipment that renders them temporarily invincible, so when they activate it, they're now charging at you, roaring, brandishing a gravity hammer, on fire, ''and'' invulnerable.
* InTheBack: [[spoiler: How the Prophet of Truth kills Miranda Keyes. [[KarmicDeath And how the Arbiter kills Truth]].]]
* ItHasBeenAnHonor:
-->'''Cortana:''' If we don't make it...
-->'''Master Chief:''' We'll make it.
-->'''Cortana:''' It's been an honor serving with you, John.
** Which itself is a CallBack to the first Halo game, when returning to the Pillar of Autumn in a captured, damaged Banshee.
** It is also worth pointing out that this is the only time in the game series to this point that Cortana has used the Chief's ''given'' name.
* LargeHam: Even more rampant than in Halo 2, with Sgt. Johnson, the shipmaster, [[EvilerThanThou Gravemind]] and a hammy [[TheOtherDarrin Prophet of Truth.]] The latter two even engage in HamToHamCombat during the 1st climax.
* LastStand: The level ''The Covenant'' is The Covenant's Last Stand against humanity. As such, both sides throw everything they have at each other; and it is the longest level of the trilogy.
* LevelInReverse: The Floodgate and The Storm are reverses of each other.
* MsFanservice : Cortana.
* {{Nerf}}: Dual-wielding was disabled for the Needler, and its magazine size was decreased. The needles were also changed to do all of their damage right when they hit a player (rather than doing most of it when they shattered), travel faster, and require one less hit for a [[MadeOfExplodium supercombine]].
** Dual-wielding itself was also nerfed for most weapons, especially with the Magnum; dual-wielded Magnums take almost twice as many shots to kill as one on its own.
* MythologyGag: Truth's speech in the second level ends with a quote from [[HaloCombatEvolved the first game]]'s E3 2000 trailer, albeit altered to relate to Truth instead of the entire Covenant.
--> "Your destruction is the will of the gods! And I? I ''am'' their instrument!"
* NeverFoundTheBody: [[spoiler: Master Chief. Earth assumes he's dead.]]
* OutrunTheFireball: [[spoiler:Blowing up Halo. [[InternalHomage Again]].]]
* PreMortemOneLiner: During [[spoiler: Truth's death]]:
-->[[spoiler:'''The Prophet of Truth:''' I AM TRUTH! The voice of the COVENANT!]]
-->'''Arbiter:''' [[CrowningMomentofAwesome And so, you must be silenced.]]
* [[RedEyesTakeWarning Red Eye Take Warning]]: 343 Guilty Spark, oh so much.
* SceneryPorn: Have a look around some of the outdoor levels, if you aren't too busy staying alive.
* ShoutOut: To ''VideoGame/{{Marathon}}'': Just look at [[http://static.tvtropes.org/pmwiki/pub/images/marathon_9070.jpg this picture]] now look at the [[http://halowiki.net/images/b/bb/Security_Armor_Infobox.jpg security armor]], see anything familiar?
** Also, the Marathon Man Achievement
** One of the bonus armor types was developed at a place called [[Series/RedDwarf Lister, Aigburth]] on a colony world.
** Also, the [[NinjaGaiden Hayabusa armor.]]
* ShutUpHannibal:
-->'''Prophet of Truth:''' I am Truth! The voice....of the Covenant!
-->'''Arbiter:''' [[CrowningMomentofAwesome And so, you must be silenced.]]
* ThisCannotBe: Guilty Spark upon learning you intend to destroy the Ring.
-->'''343 Guilty Spark''': [[MadnessMantra UNACCEPTABLE! UNACCEPTABLE! ABSOLUTELY UNACCEPTABLE!]] Protocol dictates action! I see now that helping you was wrong! You are a child of my makers, inheritors of all they left behind. You are Forerunner, but this ring... is '''mine'''!
* TheUnfought: [[spoiler: Truth and Gravemind.]]
* UpgradeVsPrototypeFight: The Terminals reveal that [[{{Precursors}} the Forerunners]] built an AI called Mendicant Bias to defeat [[EldritchAbomination the Flood]], but [[AIIsACrapshoot he went rogue]]. To counter him, another AI was built called Offensive Bias, as his successor. Offensive wins [[spoiler:but only because he was stalling for the Forerunners to fire the Halos that thus destroyed every organic being in the galaxy, robbing Mendicant's fleet of its crew.]]
* VillainousBreakdown: Truth, Gravemind and [[spoiler:Guilty Spark]] ends up with this. [[spoiler:Spark]]'s crackdown is the scariest one.
* TheWarSequence: The battle outside the array in the level "The Covenant". It is the final major land battle in the human-Covenant war, and the Covenant throw everything they have left at you, with the crew of ''Forward Unto Dawn'' doing likewise. Appropriately, it has more total forces and more variety of vehicles than virtually any other battle in the series. The music "[[http://www.youtube.com/watch?v=S68GmenFk2g One Final Effort]]" plays, the battle begins, and then the Covenant send '''[[HolyShitQuotient two]]''' [[SpiderTank scarabs]] against you.
* WhatCouldHaveBeen: Halo 2 was originally to have ended where Halo 3's first half left off, making much of the campaign filler and resulting in a relatively story-cramped installment.
* YourPrincessIsInAnotherCastle: At the end of the game, you drive a Warthog across an exploding landscape covered in enemies. Then your [=HUD=] shows 500 metres to go to a waypoint. Nearly made it! Then you make it to the waypoint, and another countdown starts ...
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->'''Master Chief:''' Wake me, [[VideoGame/{{Halo 4}} when you need me]].
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