Master Chief: "Sir, permission to leave the station."
Admiral Hood: "For what purpose, Master Chief?"
Master Chief: "To give the Covenant back their bomb."
The second game in the Halo series, released in 2004; it is the highest-selling game for the original Xbox.
Following the events of the first game, Master Chief arrives back at Earth, praised as a hero. In the midst of celebration, a Covenant attack begins on Earth, and Master Chief races to stop them. He learns that the Covenant are looking for something on Earth, and his quest takes him to a new Halo ring, where he explores more of the mystery behind The Flood.
The major change from the first Halo game is that the campaign is told from two different angles: that of Master Chief, and that of a member of the Covenant, a soldier in the Elite Mook race from the first game (the actual character is introduced in this game). He is known only as the Arbiter, and he was originally the leader of the Covenant forces that encountered Master Chief on the first Halo ring. Disgraced by the Covenant leaders due to his failure to stop the ring's destruction, the Arbiter is given a suicide mission that may potentially help him reclaim some of his lost honor. As the Arbiter learns more about the origin of the Halo rings and fate of the Forerunners, he eventually comes to doubt the Covenant cause...
On the gameplay side, Halo 2 introduced Dual-Wielding with a class of weapons you can pair off with any other type in the same class (this is portrayed as something only Master Chief, Covenant Elites and Covenant Brutes can do). It also featured vehicle hijacking... assuming you could get close enough to the vehicle without being gunned down or run over. Halo 2 solidified the presence of online console gaming thanks to the original XBox Live service; thanks to Halo 2's success, practically any game of nearly any genre will have at least some debate from the developers on whether or not it should feature an online component.
- Alien Sky:
- Once Master Chief gets to Delta Halo, If you have a good view of the sky, things often look... alien.
- Your first mission as the Arbiter puts you on a station at the edge of a gas giant's atmosphere. It's all angry swirling clouds.
- Art Evolution: The graphics are significantly improved from the original despite being released for the same system.
- Awesome but Impractical: In the level Metropolis, you will have a much easier time if you take the Warthog instead of the tank the devs thought you would. YMMV, but the Warthog is only good if you want to speed-run the level. If you want to destroy all opposition like the Wraiths and the Ghosts without dying, the Scorpion is your vehicle. One of your allies has a infinite ammo rocket launcher. Put them in the passenger seat, and you should be able to kill everything. ...Or put him on one of the tank's pods and pick up the guy with the second launcher halfway across the bridge? Or you could go on foot, bait a banshee, and get this.
- Badass Boast:
Lord Hood: Master Chief, you mind explaining what you're doing on that ship?
Master Chief: Sir, finishing this fight.
- Cliff Hanger: The story ends with one of the most infamous cliffhangers in all of videogaming.
- Death Seeker: The Arbiter. Pretty much comes with the job description.
- Determinator: Meta example. The only thing that ended Halo 2's online gaming scene was the original Xbox Live servers getting shut down. The game was launched on Nov 9th, 2004, and the servers officially shut down on Apr 15, 2010. Officially, that is; several players hung on until getting booted on May 11th.
- Dual-Wielding: The first game to have a set of weapons that you can randomly pair with other designated one-handed weapons.
- Early-Bird Cameo: An example map in the PC port includes a version of the SMG with a slightly-smaller magazine and a suppressor. This silenced SMG returned in Halo 3: ODST as the primary weapon of the titular ODST squad.
- Enemy Civil War: Following the assassination of the Prophet of Regret, the Elites are kicked out of the Covenent and replaced with the Brutes. The Elites do not take kindly to this.
- Enemy Mine: The Gravemind recruits Master Chief and the Arbiter, making it a three way enemy mine.
- Hoist by His Own Petard: After the Chief deactivates the antimatter bomb on board Cairo Station, he proceeds to take it down to a hangar, open the doors, and use the decompression to hurl the bomb toward a Covenant carrier. But wait, that's not all! He grabs hold of the bomb so that he can activate it right inside the carrier's reactor, before jumping off again and landing on a passing frigate.
- Justified Tutorial: Master Chief gets an upgraded armor system (Mjolnir Mark VI) that gives an In-Universe explanation for some of the gameplay changes (no more need for health packs, supposedly there is an internal "bio foam" system). As well, the technicians have him look around to get adjusted to the new armor.
- Made of Explodium: Covenant vehicles in this game, more so than the other games. Do enough damage and they violently explode. Twice.
- The Missingno: The Gravemind mission has the "Honor Guard Councillor", a Zealot (gold) elite that was accidentally programmed to have a "dogmatic" voice/personality; since the level has no permutation data for dogmatic Elites, it defaults to Honor Guard armor and Ultra palette, with randomly chosen head types (most frequently the Councillor, hence the nickname).
- Neo Africa: New Mombasa, Kenya is a high tech city and spaceport. At least, when the game begins.
- Retcon: Master Chief (with Cortana) was the only human to survive the destruction of the first Halo. The Legendary ending of the first game even gave a (humorous non-canon) scene depicting Johnson's last moments before the Autumn exploded. This game just has him show up in the medal ceremony with no explanation given. The expanded universe had to explain how he survived.
- Lampshaded shortly after Johnson first reappears:
Mst. Sgt. Gunns: So, Johnson, when you gonna tell me how you made it back home in one piece?
Sgt. Johnson: Sorry Gunns, it's classified.
Mst. Sgt. Gunns: My ass! Well you can forget about those adjustments to your A2 scope, and... (continues shouting as Johnson and Chief move out of earshot)
- Right Hand Versus Left Hand: The Covenant infighting between the Brutes and the Elites leads to a schism in the Covenant and basically the only hope for Humanity's survival.
- Sequel Hook: Also one of the most infamous ones in video game history.
- Trailers Always Lie:
- The E3 demo (and the advertising, and the boxart) gave the impression that the game would be set on Earth's surface. The final game had a grand total of two levels set there.
- In a more straight version of the trope, the "Give them back their bomb" sequence in the trailer has Earth in much more trouble than in the actual game, in which the Covenant barely stick around for. Earth's on fire? Not really.
- Two-Part Trilogy
- Two Lines, No Waiting: The game is divided between master Chief and the Arbiter. Gameplay wise they play almost the same.
- Wham! Episode: The cutscenes between "Quarantine Zone" and "Gravemind": the Flood have a leader, and the Enemy Civil War begins.