Halo (Halo 3 level)

Are you looking for Halo, the Forerunner Structure or Halo, the Halo: Combat Evolved level?

Halo is the tenth campaign mission of Halo 3. It is the final level of Halo 3, and the the final level of the Halo Trilogy. It is also the second mission in the Halo series to bear the name, following the second mission of the first game. Upon completing it on Normal or higher the player unlocks the Return achievement. If the player gets 15,000 or more in the meta game they will unlock the Reclaimer achievement.

Plot
After making it to the Installation near the Ark, on a Pelican, Johnson (he takes the Warthog near the hill so he can cover you with his Spartan Laser), John and the Arbiter Thel 'Vadam attempt to activate the ring using the Index from Alpha Halo. They make it to an area that almost perfectly resembles the area leading up to the Control Room in Halo: Combat Evolved. However, Gravemind sends Flood Combat Forms (and later Pure Forms), carried by Flood Dispersal Pods, to try to stop them.

After fighting through the Flood, the three make it to the Control Room. When they try to activate the ring, 343 Guilty Spark resists, saying it would destroy Halo, and possibly the Ark as well. He fires an energy beam, and hits Johnson (eventually killing him). Thel 'Vadam is then locked out of the room, and the Master Chief is pinned to the ground.

John begins to fight the Monitor, but cannot do any damage with his weapons. However, 343 Guilty Spark doesn't realize that Johnson is still not dead and is charging his Spartan Laser, which hits the monitor with a blast so powerful that it knocks him back to the controls. John then takes the laser and finishes Spark off. However, Johnson is mortally wounded. He dies, his final words being "Send me out with a bang," and the Master Chief and 'Vadam activate the Halo. They then have to flee to the Frigate, Forward Unto Dawn, culminating in an extended Warthog race back to the ship, in allusion to The Maw in Halo: Combat Evolved. Cortana tells you that the Warthog is Johnson's. Along the way there will be Sentinels and Flood will be attacking you the whole way and the panels beneath you drop if you are too slow. Finally, once you reach the end of the level you ramp into the ship where 'Vadam is almost killed by a a sliding tank and John 117 grips onto the edge of the ship as he is almost crushed by the same tank and is and nearly sucked into the explosion of the new Halo ring.

Cortana is uploaded to the Frigate and guides it out towards the Slipspace portal located above the Ark. Due to the incomplete nature of the Installation; the firing mechanism destroys the new Alpha Halo and damages the Ark. Only the front half the ship makes it through the portal, with 'Vadam in tow; Spoiler Warning for Special Legendary Ending the other half is floating somewhere in deep space with the Master Chief and Cortana. They are headed towards an unknown planet Cortana sends out a tracking beacon, while John puts himself in a cryogenic chamber. At the end of the game, he said, "Wake me... when you need me."

Back on Earth, in March of 2553, a monument is dedicated to the war and all those who perished in it. Thel 'Vadam pledges his friendship with humanity before leaving the system on the Shadow of Intent. The cut scene ends showing "117" carved into the memorial.

In the Legendary ending, after an unknown amount of time, the part of the ship John is seen drifting towards an unknown planet just as a sun rises over its surface.

Transcript
The Chief, 'Vadam & Cortana's Pelican leaves the Ark's atmosphere, passing the Shadow of Intent.

{Cut scene}
 * Rtas 'Vadum: "We are aboard, Humans and Elites".


 * Unknown Elite Officer : "Will you not come with us, brother?"


 * Thel 'Vadam: "No. This is our fight. And I will see it finished."

The Pelican flies towards the Halo ring.


 * Cortana: "Johnson? Do you have the Frigate?"


 * Sergeant Johnson (Video COM): "Yes ma'am. I'll land her as close to the control room as I can."


 * Cortana: "Safe is better than close, Sergeant Major."


 * Sergeant Johnson (Video COM): "Roger that. And ma'am? It's good to have you back."

''The Pelican arrives at Halo. The Rear Port engine is too damaged for a normal landing. The Master Chief makes a crash landing in a snowy canyon near the Control Room. The Chief and Thel 'Vadam clamber out. From behind the cliffs approaches the Forward Unto Dawn.''.


 * Cortana: "Halo. It's so new... unfinished. I'm not exactly sure what will happen when we fire it."

'Vadam tosses the Chief a MA5C Assault Rifle


 * Master Chief: "We'll head for the Portal. And we'll all go home."

Full Circle
Assault on the Control Room.

{Game play}

The Chief and 'Vadam mount up to the control room, ensuring they stock up enough supplies from their crashed Pelican.


 * Cortana: "Head through the cliffs."

The Chief and 'Vadam head through the icy caves.

If the Chief does not head to the Control Room at all..


 * Cortana: "The Control Room isn't far!"

If the Chief heads for the Terminal instead..


 * Cortana: "Where are you going?"

When the Chief reaches the Terminal


 * Cortana: "Wait, what's that?"

After accessing the Terminal.


 * Cortana: "How many of these have you found?"

If the Chief re-accesses the Terminal, or takes too long reading it.


 * Cortana: "Come on, Chief, let's get back on track. The Control Room is outside!"

''The Chief and 'Vadam arrive at the Structure. Flood Dispersal Pods begin to drop in.''


 * Gravemind: "Did you think me defeated?"


 * Cortana: "Flood Dispersal Pods! The Control Room's at the top of that tower Chief; go!"

If the Chief has been to the wrong side of the tower for a while.


 * Cortana: "There should be ramps that lead to the top - check the other side!"

The Master Chief and Thel 'Vadam push their way up the tower, but the Flood continues to attack with overwhelming force.

''Johnson appears on the cliff with a Spartan Laser.


 * Sergeant Johnson (COM): "I got you covered Chief. Meet you at the top of that tower."

If you head back the other way:


 * Sergeant Johnson (COM): "Careful, I can't cover you on the far side."

Master Chief and 'Vadam continue upward.


 * Sergeant Johnson (COM): "Keep moving, Chief. I've got your back."

''The Master Chief and Thel 'Vadam get closer to the top. Johnson continues his reign of terror from the cliff.''


 * Sergeant Johnson (COM): "Flood are crawling all over that tower; watch yourself."

The Chief reachs the top floor.

''Flood jump down the tower and attack 'Vadam.


 * Sergeant Johnson (COM): "Spark? You in there? Open the damn door!


 * 343 Guilty Spark (COM): "Of course, Reclaimer. As soon as you dispose of all proximate Flood threats. I'm afraid containment protocols do not allow..."


 * Sergeant Johnson (COM): (Impatiently) "Yeah, yeah, I hear you!"


 * Cortana: "Was that the Monitor? You didn't tell me he was here. Well, we are finally doing what he wanted."

The Flood continues to stubbornly attack with extreme force on the top floor.

The Chief, Thel 'Vadam & Johnson finally secure the tower.


 * Sergeant Johnson: "Open up! The coast is clear."


 * Cortana (COM): "Not for long. I'm tracking additional Dispersal Pods. They'll be hitting any minute!"


 * Sergeant Johnson: "Chief! Arbiter! Let's move!"


 * Gravemind: "I have beaten fleets of thousands! Consumed a galaxy of flesh and mind and bone!"

As the trio moves inside the Control Room.


 * Gravemind (Gravemind Moment): "Do I take life or give it? Who is victim? And who is foe?"


 * Cortana: "It's trying to rebuild itself on this ring!"


 * Sergeant Johnson: "Hurry! Control Room's close!"

{Cut scene}

''The Chief, Thel 'Vadam & Johnson reach the familiar Control Room. Flood are heard approaching, but the doors seal them out.''


 * Cortana: "Yank me, Chief."

The Chief removes Cortana from his helmet.


 * Sergeant Johnson: "I'm not gonna lose her too."

''The Chief tosses Cortana to Johnson. Johnson heads for the control panel. 343 Guilty Spark appears from above.''


 * 343 Guilty Spark: (Humming to himself) "Oh, hello! Wonderful news - the Installation is almost complete!"


 * Sergeant Johnson: (Uninterested) "Terrific."


 * 343 Guilty Spark: "Yes... isn't it? (Short but uneasy silence.) I have begun my simulations. No promises, but initial results indicate that this facility should be ready to fire in just a few more days!"


 * Sergeant Johnson: (Impatiently) "We don't have a few more days!"


 * 343 Guilty Spark: (Alarmed) "Bu-bu-but a premature firing will destroy the Ark!"


 * Sergeant Johnson: "Deal with it."


 * 343 Guilty Spark: (Quietly) "...Will destroy this Installation."

Guilty Spark suddenly turns red and shoots Johnson with his Beam.


 * Sergeant Johnson: (Screams) "AAAAAAAAAAAHHHHHHHHHH!!!!"


 * 343 Guilty Spark: "Unacceptable! Unacceptable! Absolutely unacceptable!"

''The Chief rushes to Johnson's aid. 343 Guilty Spark shoots at the the Chief, who is flung backwards and onto the floor. His Energy Shields drop and attempt to recharge. ''


 * 343 Guilty Spark: (In hysterics) "Protocol dictates action! I see now that helping you was wrong!"

''Thel 'Vadam, hearing the commotion, moves forward, and 343 Guilty Spark turns on him as well, unleashing his beam on him and knocking him out of the Control Room. He blasts the Chief again as he tries to get back up. With no shields protecting him this time, his armor starts to smoke.''


 * 343 Guilty Spark: (His eye turns Blue) You are the child of my makers. Inheritor of all they left behind. You are Forerunner! But this ring... (Eye turns Red again) ...is mine!

{Game play}


 * 343 Guilty Spark: "I take no pleasure in doing what must be done."

The Chief fires at 343 Guilty Spark with no effect at all.


 * 343 Guilty Spark: "You do not deserve this ring!"

343 Guilty Spark corners the Master Chief.


 * 343 Guilty Spark: "I have kept it safe. It belongs to me!"


 * Sergeant Johnson: "Not for long!"

''Johnson shoots 343 Guilty Spark with his Spartan Laser. Caught off-guard, 343 Guilty Spark is blasted away from the Chief.''


 * Johnson: "Kick his ass."

''Johnson passes out. The Chief takes the Spartan Laser to destroy Guilty Spark.''

''343 Guilty Spark rises from the floor, flying at a slightly tilted angle. At this point, 343 Guilty Spark will say four sentences at random.''


 * 343 Guilty Spark: "You - you cracked my casing!"


 * 343 Guilty Spark: "Damn it! Damn it! That hurt, Reclaimer!"


 * 343 Guilty Spark: "My eye! Do you mean to blind me!?"


 * 343 Guilty Spark: "Stop now, before one of us gets hurt!"

''After making the first shot, Spark begins to fly at a more tilted angle, leaking blue plasma from his sides and he begins to spark. Again, the following sentences are in random order.''


 * 343 Guilty Spark: (Voice breaks, then readjusts itself) "-destroy your Inheritance!"


 * 343 Guilty Spark: "Accept your le-gacy!"


 * 343 Guilty Spark: "Think of you-ou-ou-our forerunner!"

''Following the second shot, Spark's casing becomes distorted, with pieces of him sheared off. More plasma leaks from his sides and he sparks more ferociously. The right side of his 'eye' has broken off. Once again, the following sentences are said in a random order.''


 * 343 Guilty Spark: (Makes a garbled humming sound)


 * 343 Guilty Spark: (High, crackling voice) "M-m-my pr-precious!" (This is a reference to The Lord of the Rings)


 * 343 Guilty Spark: (Deteriorating, breaking voice) "I a-a-a-am the Monitor of Installation Z-Zero F-Four!"

After making the finishing shot.


 * 343 Guilty Spark: "Oh myyyyyyyyyy-aaahh!"

Guilty Spark explodes, defeated.

{Cut scene}

Master Chief bends over Johnson, who is still - barely - alive.;


 * Master Chief: "I'm getting you out of here."


 * Sergeant Johnson: "No... No you're not."

Johnson grabs the Chief's hand with Cortana's chip in his.


 * Sergeant Johnson: "Don't - don't let her go. Don't... ever let her go. (Coughs) Send me out... with a bang."

''Johnson succumbs to his wounds. The Chief takes Cortana from him and lets go of his hand. He stands up, and lets Cortana enter Halo's core, but doesn't let go of Cortana's chip.''

Cortana: (Looks down sadly at Johnson's body) "Chief... I'm so sorry."

''The Master Chief shakes a bit with his hand but quickly stops. Cortana bows her head, eyes closed, and makes a gesture, activating Halo. She uploads herself back into her chip.''

''The Chief places her chip in the back of his helmet, and then turns around. Brilliant beams of light erupt from the Core, and the whole Control Room starts to fall apart. Johnson's body slides off the platform as it begins to fall. The Master Chief runs for the door, which has opened again.''

The Way the World Ends
Pedal to the Metal.

{Game play}






 * Thel 'Vadam: "I am sorry, Spartan. But come."

The Master Chief and 'Vadam make it back outside.


 * Thel 'Vadam: "Even in death, your Sergeant guides us all."


 * Cortana: "The Dawn. Of course - the Frigate! We still have a chance!"


 * Cortana: "Find the doorway in the cliffs, Chief. The Dawn is on the other side."

The Chief and 'Vadam head along the cliff, encountering Flood and Sentinels, who followed 343 Guilty Spark's lead and turned against them too. They make it inside, and find themselves in the middle of a battle, between Flood and Sentinels.''


 * Gravemind: "Resignation is my virtue. Like water I ebb and flow. Defeat is simply the addition of time to a sentence I never deserved... but you imposed."


 * Cortana: "Don't let this ring be the end of us, Chief."

They make it back outside.


 * Cortana: "There! Johnson's Warthog."

'''Vadam takes the turret. The Chief takes the wheel.''


 * Cortana: "Come on, Spartan - GO, GO, GO!"

As they reach open area, a massive explosion erupts alongside them.


 * Cortana: "Drive, Chief. Head for the Frigate."




 * Cortana: "Come on! Faster!"

The Chief and 'Vadam reach a massive open structure.


 * Cortana: "The Dawn is close. We can make it! As long as the ground doesn't fall out from beneath us..."

The Warthog soon enters inside the interior of a large Hallway with ramps.


 * Cortana: "The charging sequence - it's too much for the ring to take!"

They soon reach another open structure where battle between Flood and a few Sentinels ensues.


 * Cortana: "Halo is ripping itself apart!"

They come upon a large open stretch.


 * Cortana: "Hurry Chief! Don't stop!"


 * Cortana: "Charging sequence at 30%..."

They reach one more open structure, this time a few Flood Pure Forms awaits them.


 * Cortana: "50%, Chief!"

They reach another Hallway with ramps, where a larger battle between Sentinels and Flood ensues.


 * Cortana: "70%!"

The Chief and 'Vadam makes it out of the Hallway battle, where the Frigate can be seen from a distance.
 * Cortana: "80% charged."

They head for the final bend, encountering more Sentinels.


 * Cortana: (Desperately) "90% - firing sequence initiated!"

''If the Chief heads to a Grunt Easter Egg


 * Final Grunt: "Hey, Demon! The jerk store called, and they're all out of you! Poor you, stolen at the age of six and conscripted into the military, eeeeegh! ...Okay look, if you let me live, I got the Fist of Rukt. I'll be the bomb! I'll polish your boots. I'll polish your helmet! It's the gas, haha! When I'm on the gas, I don't know what I'm doing half the time!"

The Chief and 'Vadam make it to the final straight stretch to the Forward Unto Dawn, but there's a 70m (230ft) gap to it.


 * Cortana: "Gun it, Chief!! Jump!! Floor it; right into the hangar!!"

{Cut scene}

''The Warthog tumbles and rolls as it crashes into the Frigate's hangar. The Master Chief and 'Vadam recover, then the Dawn shifts. A Scorpion Tank begins sliding towards Thel 'Vadam, who takes cover behind a pile of crates. The tank plows into it. The Chief leaps over the Warthog, looking back, seeing 'Vadam digging himself out of the crates. The Chief nods at him, who nods back. 'Vadam rushes to the bridge while the Chief runs to the hangar panel and plugs Cortana in to start up the Frigate. Her image appears from a Holotank next to the panel.''


 * Cortana: "Hang on!"

Cortana ignites the thrusters at full burn and launches the Dawn'' at full speed. The Chief grabs onto the terminal. The Dawn leaves Halo's atmosphere. As the Chief holds on for dear life, the Warthog flies out, hitting the Chief, who flies off the panel, then glides down the floor towards the open hangar doors, with Halo beneath. The Chief punches his fist hard into the floor to get a grip, halting near the back end of the hangar. Cortana reaches out her arm towards him, scared of losing him.''


 * Cortana: "Chief!!"

''The Scorpion flies out towards the Chief. He ducks his head just in time as it flies over him, narrowly missing the Chief but smashing the floor behind him and falling back towards Halo. The Chief begins to back climb up to Cortana, finally making it back to the panel. Thel 'Vadam makes it to the bridge and takes control of the ship. The Chief braces behind the panel, plugging Cortana back into his helmet.''


 * Cortana: "If we don't make it--"


 * Master Chief: "We'll make it."


 * Cortana: "It's been an honor serving with you, John."

''Halo's explosion engulfs the hangar in a strobe-binding white light. All goes blank.''

The Storm Has Passed (March 3 2553)
''On a hillside near the Gateway to the Ark, Marines gather. Lord Hood removes his hat, and begins his speech.''


 * Admiral Hood: "For us, the storm has passed. The war is over. But let us never forget those who journeyed into the howling dark and did not return. For their decision required courage beyond measure..."

{Background Memory: The front half of the Forward Unto Dawn enters the Earth's atmosphere, and crashes into an ocean)


 * Admiral Hood: "...sacrifice, and unshakable conviction that their fight, our fight, was elsewhere."

{Background Memory continued: An engineer crew cuts into the Dawn. Thel 'Vadam is freed from the wreckage.}

'Vadam is revealed on the hill, standing solemnly with the Marines.


 * Admiral Hood: "(Concluded) As we start to rebuild, this hillside will remain barren, a memorial to heroes fallen. They ennobled all of us, and they shall not be forgotten."

Admiral Hood puts his hat back on, and salutes.


 * Sergeant Stacker: "Present arms!"

''7 marines raise their BR55HB SR Battle Rifles and each fire a single burst of three shots: a 3-volley salute. The view pans over the Ark Portal, now closed and silent, and Mt. Kilimanjaro against the evening sky.

Later, Admiral Hood and 'Vadam stand alone at the Memorial, which looks like a Pelican wing, decorated with pictures of those fallen, including Commander Miranda Keyes and Sergeant Major Avery Johnson''.


 * Admiral Hood: "I remember how this war started. What your kind did to mine. I can't forgive you. But... (he holds out his hand) you have my thanks, for standing by him to the end."

'Vadam slowly shakes Admiral Hood's hand.


 * Admiral Hood: "Hard to believe he's dead."

'Vadam looks away, toward the Shadow of Intent, hovering silently in the sky.


 * Thel 'Vadam: "Were it so easy."

'''Vadam leaves the Memorial. His Separatist Phantom heads back to the Shadow of Intent, hovering above the Gateway to the Ark, which has lowered flat again. 'Vadam meets Ship master Rtas 'Vadum on the bridge, looking at a holographic image of Earth.''


 * Ship master Rtas 'Vadum: "Things look different without the Prophets' lies clouding my vision. I would like to see our own world - to know that it is safe."


 * Thel 'Vadam?: "Fear not. For we have made it so."

The Arbiter clenches a fist to his chest.


 * Ship master Rtas 'Vadum: "By your word, Arbiter." (clenches his fist to his chest as well.)

'Vadam takes a seat on the chair, the ones used by the Prophets.


 * Thel 'Vadam: "Take us home."

The Shadow of Intent'' leaves Planet Earth, to rejoin the remains of the Covenant Separatist fleet in space. Going back to the memorial, the view shows that underneath the print "UNSCDF March 3 2553", the number "117" is scratched in and the rank of Master Chief Petty Officer is taped to the upper right of it as a tribute to Master Chief.''

After Credits

 * Cortana: "Chief?! Can you hear me?"

The Master Chief, very much alive, awakes floating in a debris-filled hallway on board the Dawn.


 * Cortana: ''(Exhaling) "I thought I'd lost you, too."

''The Master Chief looks at a gaping hole in the hallway. He drifts to his Assault Rifle, and holsters it, then begins to drift to the end of the open hallway.''


 * Master Chief: "What happened?"


 * Cortana: "I'm not sure. When Halo fired, it shook itself to pieces. Did a number on the Ark. The Portal couldn't sustain itself. We made it through just as it collapsed."

Forward Unto Dawn is revealed to be sheared in half, floating in a cloud of its own debris, still red-hot from the sudden Slip space slowdown.


 * Cortana: "Well… some of us made it."

The Dawn's remaining half continues to drift aimlessly in unexplored space.

The Chief begins to drift further inside the ship, finding a panel to plug Cortana in.


 * Cortana: "But you did it. Truth and the Covenant...The Flood... (she's plugged into the panel and appears) It's finished."


 * Master Chief: (Turns off his headlight) "It's finished."

Master Chief places his Assault Rifle in one of the rackets on the wall.


 * Cortana: "I'll drop a beacon. But it'll be a while before anyone finds us."

The Chief places himself in one of the Cryotubes.


 * Cortana: "Years, even."

The Cryotube door begins to close.


 * Cortana: "I'll miss you."


 * Master Chief: "Wake me....when you need me."

Cortana smiles back,nodding.The Cryotube seals, freezing the Chief and bringing the Halo Trilogy to full circle.

- Legendary Segment: (The back half of the Forward Unto Dawn'' is seen drifting towards an unknown planet. The planet eclipses a star at first, but the star slowly comes out from behind the planet, casting light upon it momentarily before blinding the view completely.)

Legendary Rumors
There have been many rumors that the unknown planet seen at the end of the game is Onyx. However, this cannot be true because at the end of Halo: Ghosts of Onyx, Onyx was destroyed after trillions of sentinels emerged from the planet. Also, Onyx only existed in Slipspace, and the severed half of the Forward Unto Dawn would have to be traveling through Slipspace in order to find the planet. There have also been rumors that it is the Micro Dyson Sphere that Dr. Halsey, Chief Mendez, and the remaining Spartan-IIs and IIIs are trapped in. However, the object Forward Unto Dawn drifts to was colossal when compared to the Dyson Sphere, which Dr. Halsey explained was only a few meters in diameter externally.

Some fans also believe the planetoid to be the UESC Marathon, although Bungie stated that Halo and the Marathon trilogy were set in different universe.

Light formations resembling those of a Forerunner civilization can be seen on the planet, confirming that the object is of Forerunner origin. What it is or its purpose, whether it is a Shield World is unknown, and will probably remain so.

Walkthrough
When the level starts simply follow the corridor until you reach the installation. It's here that Gravemind starts his final offensive, air-dropping a massive amount of Flood Combat units on you in dispersal pods. If you're hurting for ammo after the last level (which you shouldn't be, since there's fresh Battle Rifles, Shotguns, an S.M.G., and a Rocket Launcher at the Pelican crash site), but if you are, take out any armed Flood first. Depending on your skill and the difficulty level, try stocking up on a Gravity Hammer, Energy Sword, or even a Brute Shot--anything with a strong melee attack. Another good tactic is to stand on the shelf above the entrance to the tunnel from which you came, because the flood won't attack to up here, giving you freedom to take them all out with a Battle Rifle or Carbine. Plasma Rifles are also very effective and allow you to take out the Flood before they get to melee range (plus most Elite Flood forms drop them, so there are a lot). There's lots of Flood and only so much ammo you can scavenge. The first Flood you'll find will be a Brute Form who is wielding a Gravity Hammer. If you look immediately to your right, you'll find a Fuel Rod Cannon on a small hill.

Wind your way up the Control Room as Cortana instructs you to do. However, if you walk along the left side of the Control Room, you can find a rocket launcher with the maximum amount of ammo. You can run straight ahead and let the Arbiter (or your friends) deal with the Flood, but it helps to do your part and cut down their numbers. The way up to the next level of the structure is always at the opposite end of where you first climb up, so you're in for a lot of action.

When you hit the top of the fortress, you'll hear from 343 Guilty Spark that he won't open the door until all the Flood attacking you are destroyed for security, so be ready to go on the defensive. A ton of Stalker, Ranged, Tank, Human, Elite, and Brute Combat Forms will land near you and swarm from all directions. In single player mode, give the Arbiter plenty of room to do his thing and do your part in killing some Flood. There is an Invincibility in an alcove across from the doors. It may or may not appear, so don't always count on it. A good strategy for dealing with the tides of Flood is to melee any Flood-form you see in the midst of resurrecting or upgrading; it'll prevent them from getting back up, and, if you hit them bad enough, it'll shatter their corpse, rendering it useless for reanimation. Keep a Shotgun for close quarters and a powerful weapon, like the Rocket Launcher, Fuel Rod or Battle Rifle for the various Forms. If you have any Incendiary Grenades, use them to burn away corpses. If you are having a lot of difficulty on this part, you can drop back down to the ground below and fight your way back up, thus mitigating the Flood's ability to swarm and attack  you from every direction. Another way to ease the pressure being put on you is to take the two Auto Turrets that are conveniently placed right in front of the door. Pick them up and activate them in approximately the same place they were laying, facing the Flood opposition. If they are still there after all the Flood are dead, destroy them. They aren't going to remain friendly to you for much longer, and you will have to retrace your steps back through here. On Legendary, they will cut you down in about a second.

After clearing the infestation, you have a few moments to calm down and get some ammo. If you want to retain any weapons you have right now later on, swap them out for something else. You lose all of your guns and grenades after the control room segment. The only way to keep them is to keep them on the ground out here. It doesn't really matter what you pick up in exchange, as you will get the only weapon you need up ahead. So swap out your weapons and follow Guilty Spark into the control room, watch the cinematic, and prepare for what could be considered the only boss in Halo 3: 343 Guilty Spark.

Guilty Spark has two main combat modes: one is a massive spherical shield that pushes you back and protects him from harm, and the other is an extremely powerful version of the Sentinel Beam. Play defensive--even without that shield, Guilty Spark's mighty construction keeps him from harm. Try to stay near the center of the bridge, as his shield can push you off the edge if you stray too close. If you have retained a Bubble Shield from outside, now is the time to use it. Back all the way up against the center of the door, deploy it, and stay inside. It blocks Spark's beam and you don't really need to return fire right now anyways, as all of your current weapons are basically useless against him. When Johnson blasts him with the Spartan Laser, run up to Johnson and swap weapons. Guilty Spark is just the right size to fit into the reticule of your rifle, and he stays still too. That beam is deadly, so stay careful. Blast Spark three times to defeat him.

First things first: be ready to alternate between shooting and running. Any weapons you had before are now gone: you have just an Assault Rifle with 3 magazines and no grenades, nothing else. Suffice it to say, you're outgunned here. No matter, two Elite Forms will appear with about 15-20 Infection Forms. Kill them, and grab the Plasma Rifles the Elites dropped. Outside, the Sentinels that were your allies are now your enemies. Destroy them, and grab weapons from the corpses from the previous battle (before you entered the Control Room). Head up the ice slope which is directly to the left of the entrance to the Control Room (facing towards the entrance). Be careful though, if you set up those Auto Turrets; they will kill you almost instantly as you exit the Control Room. Take the ice bridge directly to the right of the entrance and follow it to a cave. Mow down the Combat Forms in your way, and grab the plentiful Assault Rifle ammo they drop. Inside the room, a battle between Sentinels and Flood is taking place. Lighten their ranks with AR fire, and head down the hallway. Stick the Carrier Forms with Plasma grenades, and continue to the left up a ramp. Shoot the swarm of Infection Forms, and head out. A Warthog sits there, so board it and floor it. However, if you like a challenge, head to the left before you reach the tiles. Depending on the difficulty, a Mongoose sits in the corner on a platform, or a pair of Brute Choppers. The Mongoose is especially hard to complete the level on, due its lighter weight, slower speed, acceleration time, lack of clearing jumps, and lack of on board weapons. The Brute Choppers are slow too, but their on board boost alleviates the problem somewhat. The 35mm auto cannons are good for tearing through Flood and Sentinels.

Escape is, to say the least, tricky. Trust in the Arbiter (or your multi-player pals) to shoot any oncoming Flood, and watch where you're driving. Halo is in the middle of activating and destroying itself. When you see an explosion, stay away from where it was. Those panels are gone now, and the only thing underneath them is instant death. Keep your cool, watch for where the ground is solid, and keep note of where you see the plumes of fire marking the explosions. You'll find Flood in straight-aways, so feel free to step on the gas and dodge the falling debris. The Flood aren't too much of a threat in this area. Just be sure not to splatter carrier forms, as they are practically waddling trip mines. The panels are falling behind you, so don't screw around for too long. The way is pretty straightforward, so don't worry about getting lost. The Sentinels can be a major threat on Legendary, not only because their Sentinel beams do a fair amount of damage, but their beams are able to push your vehicle. In the Warthog, you mostly just have to worry about this during jumps, but in the Mongoose the beams should be avoided as much as possible, as they can and will flip your vehicle even on completely flat terrain.

You'll eventually reach a series of roundabouts. Follow the red-tile road to find the path off of them before they explode and plummet to the ground below, taking you with them. You'll reach the end of the path eventually--when you see the ship over in the distance, you'll know you're near the end. When you finally see the frigate pull in front of you, go straight and fast and take the jump. Do not slow down here, the panels will start falling the instant you enter this area.

It can be a really good feeling when you beat this level, and a bit sad, especially after watching the ending. Although it's disheartening that the original Halo trilogy is over, you'll know that you finally defeated the Covenant, and eliminated all the Flood on Installation 04.

Watch the ending, stay for the credits and hit the next level of difficulty! Halo 3 is short, but legendary and sweet, and there's always one more challenge over the hill to face against the Covenant and the Flood. On Legendary starting from mission start, after destroying 343 Guilty Spark, and the two Combat Forms and Infection Form, outside the doorway, jump down a floor to your left and you will find some Ghosts. Then, when you are in the Warthog, right before you are heading into the exploding tiles turn left past the two rocks and you will see two Choppers.

Halo - It's finished...

Cooperative Walkthrough (With the final Terminal location)
Here we go. Time to finish this once and for all. If you started a new game, both players should have an Assault/Plasma Rifle and a Heavy Weapon. If you just finished Cortana, you should have your previous weapons, which will most likely be low on ammo. Switch any weapon you want for a Shotgun, and keep your heavy weapons, if you have them. Move out.

Seventh Terminal: When you see a few beams extending across an icy ceiling, turn right, and jump over the snowy ledge onto an extending beam. There should be a doorway. Walk down the hall, and facing you should be the terminal.

Return outside, and move on. Flood dispersal pods will drop. Take care of the Hammer-wielding one, and take it. If you don't have heavy weapons, move to the opposite end of the pyramid. There will be a Rocket Launcher and a Fuel Rod Cannon. Move back up.

Player one should take the Flamethrower, and player two should cover him. Kill the Rangers first, they're really annoying. While Player 1 torches the enemies ahead, Player 2 should cover the six, in case of any enemies sneaking up on you. When you make it to the top, set up Auto-turrets by the door, and kill the remaining Flood. When Johnson joins you, kill him, and take his Laser away from him. Switch weapons while walking to take both weapons away. Kill him again for another one, this time infinite. Keep it by the door.

Go inside. Spark, you back-stabbing snake! Eat this! Crap, it doesn't work. Hold out, and try not to fall off the edge while Johnson recuperates and lasers him. Take the weapon and kill Spark.

Go back outside, and pick up the infinite laser. Destroy the Auto-turrets, kill the Flood with the laser, and get to the Warthog. Go.

Trivia

 * It is possible to receive more than one Spartan Laser from Johnson in the control room. Everyone must run over to him in unison as Spark pushes you towards the wall, while moving to him, hold RB, then you should all receive one if you all make it in time. May only be possible on Legendary.
 * The beginning of this level still takes place in 2552, but the memorial takes place on March 3, 2553. It is unknown why the Elites would stay at Earth so long, maybe to wait for the preparations for the memorial and pay their final respects to the fallen soldiers of the UNSC.
 * Completing this level with four people over Xbox Live on Legendary with the Iron skull on and all 4 players in a Ghost each will net the player the Vidmaster Challenge: Annual Achievement.
 * Cortana's line, "But you did it. Truth and the Covenant...The Flood... It's finished," may be a reference to one of her lines from the end of the first Halo -- "We did what we had to do ... for Earth. An entire Covenant armada obliterated, and the Flood ... we had no choice. Halo ... It's finished." In the first game, the Chief denies it, while in the third game, he agrees.
 * In the beginning of the level, the Arbiter passes an Assault Rifle to the Chief in the cutscene. However, if the player got to this level by completing the level Cortana right before, the player will start with what ever weapon he/she took from that level.
 * In a further nod to the original Halo: CE game, in the campaign lobby the Mission Start is labeled "Assault on the Control Room".
 * Whenever you get on the Warthog in single player, the Arbiter will disappear from his current position and then appear on the Warthog turret, apparently using lightning-fast movement and Active Camouflage (you can see him fade in). If you take the gunner position and then get in the driver position, the Arbiter takes the passenger seat. It is possible to "kill" the Arbiter, by driving the Warthog off a cliff, and quickly taking another vehicle, like the Mongoose. The Arbiter will not respawn on the back, and you can finish the level without him.
 * The Mythic Skull can be found in this level. If you are playing single player, you can give the skull to The Arbiter and he will use it to attack the Flood.
 * The last part of game play on this level is a remake of the Warthog escape on The Maw, the last level of the first game, only it is slightly more complex then the original Warthog Run. Also, instead of being on a timer, the ground will fall out from under you if you linger too long, and the timer varies depending on the difficulty of the game.
 * Oddly, even though High Charity is destroyed and there are no Flood controlled ships in system, Flood Dispersal Pods somehow fall from the sky. It is possible that they came from the location the Gravemind is rebuilding himself on the ring.
 * There is a Talking Grunt on this level. He tries to make fun of the Master Chief's childhood by mocking how he was kidnapped and forced into the SPARTAN-II Program. This is also a reference to Halo: CE, where the Thirsty Grunt talked on the Warthog run of the last level. He is located just before the Dawn, on an outcropping next to some rocks. If you stay to hear what he has to say, you won't be able to complete the level as the ground would have fallen away.
 * If you kill Johnson before you go into the Control Room, after you kill 343 Guilty Spark, when the door opens you can see Johnson on the floor wounded and a Flood Infection Form will convert him into a Combat Form. If you kill the Flood before they infect him, he will get up and fight with you, though he won't leave the building (since he's supposed to be dead, he has no scripted path to follow). Though if you push him all the way to the Warthog he should still get on.
 * Guilty Spark's quote of "M-m-my pr-precious!" is a mimic of Smeagol/Gollum from Lord of the Rings, who refers to The One Ring as his precious.
 * During the memorial, if one looks closely at the pictures on the memorial site, a couple of people in the pictures (Sergeant Johnson being one of them) is wearing a 21st century U.S. Marine Dress Blues uniform.
 * If you head over to the large crevasse next to the Control Room in the beginning of the level, you can look down and see an almost endless series of catwalks. You can only explore the crevasse in theater mode. In addition, after destroying 343 Guilty Spark, if you recheck the crevasse it will be distorted by energy waves caused by the rings activation in the control room. This crevasse may be similar to the 'Honeycomb' channels that are used for faster travels, power storage and that Foehammer comes out of in the beginning of the Level, Assault on the Control Room in Halo: CE.
 * The soundtrack for the second half of the level is called "Greatest Journey", however during the MJOLNIR Theme part, there are some musical parts that are not featured in the shipped version of the soundtrack title but they are featured in "To Kill a Demon" and "Three Gates" soundtrack titles.
 * To find the Terminal on this level, you must go forward from the beginning of the level. Then when you see a building to the right. Go to it, Cortana will say "Where are you going?", then when you see it she will say, as a hint, "Wait, what's that?", and, "How many of these have you found?" afterward.
 * Although positioned on a facing cliff to help kill any Flood stragglers chasing the player(s), Sergeant Johnson may occasionally shoot player(s) with his Spartan Laser, killing them instantly.
 * Throughout the fight on the ground floor with the first waves of Flood, a Rocket Launcher and a couple of Fuel Rod Cannons can be found near the lower structures of the tower, each carrying 8 Rockets and 15 Fuel Rods respectively.
 * Several parts of the Warthog Run use ice effects instead of metal. They can only be found using a Warthog and on Single Player, not Co-op.
 * This along with the levels Tsavo Highway and The Ark are the only levels to not feature Cortana Moments in Halo 3.
 * This level, and Truth's death cinematic are the only times you see Johnson without a cap on in Halo 3, except if you melee him in the head in campaign.
 * This level is very similar to the Halo: Combat Evolved levels, Assault on the Control Room and The Maw. The whole level is a sort of tribute to or model of those two levels, as the level start message on the level select scene is "Assault on the Control Room", several phrases used in those levels are used here, and there is the Warthog Run in both of the last levels. It is more a tribute to the entire game.
 * There could be two meanings to the Arbiter's words, "Were it so easy." The widely accepted and most likely meaning is that it would not be so easy to kill the Master Chief. However the second meaning may be an answer of agreement to Lord Hood's words, "It's hard to believe he's dead." He could be agreeing that it would be much harder than that to believe that he's dead. However, this is unlikely, as the Arbiter would know that the Master Chief could not be killed so easily, after all that he's been through, and all that the Covenant has done to kill him.
 * In the final cinematic with the Master Chief, if you look closely at his Assault Rifle's ammo counter, you can see that it had only one round left in the magazine.
 * If you carry the unknown skull through the level "Cortana" you will spawn with a Spartan Laser at the beginning.
 * There is a giant 7 engraved on the floor from where the beam fires in the cutscene in the control room. It can only be seen in Theater mode.
 * When you reach the top of the control room where the flood pods start coming down, wait till Cortana says something like "Well, we are finally doing what he wanted." and run down the control room and far away from it. keep making checkpoints so that lots of flood pods drop and the building will soon be covered with combat forms. As soon as the Gravemind says " I have beaten fleets of thousands... ", you should get a loading or checkpoint done. If done correctly, get up to the building and all the flood will be gone.
 * When approaching the final terminal, there's another passageway next to it with opened blast doors (not the Lonely Soul). When you enter, it shows a reference which some Halo fans considered as "haunting", as players enter the room they can see a replica of the one of the Phase Pulse Generators like the ones in Halo: Combat Evolved but, it's heavily barricaded with four pillars to prevent anyone from disrupting them like John had in Two Betrayals. In addition, the chamber itself is exactly as it appeared in Combat Evolved but with increased security measures such as, unbreakable glass and four more additional barricades surrounding the protected pulse generator. Thus, solving why the chapter of the level is called "Full Circle", signifying the full circle ending of Installation 04 and the Halo trilogy. However, if you return to this room after the cutscene in which Johnson dies, the barriers are gone, but you are unable to interrupt the beam like in Halo:CE.