Floodgate (Level)

Floodgate is the fifth and shortest Campaign mission of Halo 3 and the first Halo 3 level with the Flood.

Background
It takes place in Voi, Kenya on the continent of Africa on Earth during the Second Battle of Earth. Floodgate is also the first campaign mission where the non-playable Elites are encountered in Halo 3.

Shortly after disabling the Anti-Air Gun in The Storm, UNSC Frigates under the command of Lord Hood attack the Covenant controlled Forerunner Dreadnought. This attempt failed, and it appeared the Dreadnought survived unscathed. The Covenant Loyalists activated the Portal to the Ark, temporarily disabling the UNSC's nearby ships. The remainder of the Covenant Loyalist fleet follows the Dreadnought into the portal. With the UNSC fleet disabled, and the Anti-Air gun out of commission; a Flood-controlled Covenant CCS-class Battlecruiser comes out of Slip-space nearby and crashes into Traxus Factory Complex 09.

In order to eliminate the infestation, John-117 and the Arbiter must overload the crashed cruiser's engines, wiping out the entire city and the Flood with it. To do this, they push back through the factory where they just came from, fighting many Flood Combat Forms, including a new Flood species, the Pure Forms. They are then aided by the arrival of Rtas 'Vadum and the Covenant Separatist fleet. The Arbiter and Chief, along with some Elites, push forward to the crashed ship, and the Arbiter holds position while the Chief extracts what is believed to be Cortana, stored in a Covenant Storage Device. This eventually turns out to be only a recording.

Once on the Covenant ship, Shadow of Intent, 343 Guilty Spark extracts Cortana's recorded message from the Covenant Storage Device. The UNSC and Covenant Separatists begin to prepare for the voyage to The Ark. While doing so, Covenant warships begin to glass Voi and the immediate vicinity to prevent further contamination by the Flood.

Upon completing it on the Normal, Heroic, or Legendary difficulties, the player will earn the "Cleansing" achievement and 30 Gamerpoints. Earning over 15,000 points in the Campaign meta-game will give the player the Exterminator achievement and 10 Gamerpoints.

Transcript
Note: In co-op game play, the Arbiter doesn't speak, and real time conversations including him do not play.

It Followed Me Home
'Hot zone. Weapons free.'

{Gameplay}


 * Commander Keyes (COM): "The Flood - it's spreading all over the city."


 * Lord Hood (COM): "How do we contain it?"


 * Commander Keyes (COM): "Find the crashed Flood ship; overload its engine core. We either destroy this city, or risk losing the entire planet."


 * Lord Hood (COM): "Do it."


 * Miranda Keyes (COM): "Chief, make your way to the crash site."

''To the right of a couple of Marines are seen on the cliff edge fighting off several Flood Combat forms. They typically are overrun and mutate into more Combat forms. Occasionally however, the marines survive, and run out of view (the flood 'mist' obscures them)''

Sometime later, when the Chief and the Arbiter re-enters the city.


 * Marine Officer of NCO(COM): "All squads, report!"


 * Marine Sergeant (COM): "Multiple contacts, unknown hostiles."


 * Arbiter: (May vary upon difficulty setting) "There are some powerful weapons we've not yet used..."

You find a group of Marines in a loading ramp.


 * Marine (COM): "There! Over there! We are surrounded, Sergeant!"


 * Marine (COM): "Aaaaah!"


 * Marine Sergeant (COM): "Fall back, fall back!"


 * Female Marine: "Sergeant, come on!"

Infection Forms and Combat Forms (Including the Brute ones) descend and swarm on the Marines at the ramp, infecting and killing them, forcing the other Marines, the Chief, and Arbiter to kill them.


 * Female Marine: "What are you doing?!"


 * Marine: "That's not the Sergeant. Not anymore."

They fight off the current wave of Flood.


 * Arbiter: "Quickly! Let us find their ship. Make short work of this abomination!"

The Marines accompany the Chief and Arbiter into a building, where a lone Marine fights off a horde of infection forms. {It is possible to save him, but more often than not, he will be mutated before your eyes}


 * Infected Marine: "Uhh! Get off me!"

or


 * Infected Marine: "Get it off! Get it off!"

''If the Marine is not saved, the Infection Form dives into the Marine's chest, causing his back to swell and his skin to change to a darker tan color. He collapses to the floor then Whip Tentacles grow out of his left arm and then the sensors on the Infection Form erupt out of his chest wound, ending the grim transformation. This forces the Chief and the Arbiter to immediately kill him.''

''Marines are pinned down behind sandbags with lots of Flood surrounding the area. The Chief and Arbiter clear the section of the warehouse.''

If the Marines are saved from being killed or infected.


 * Female Marine : "It gets inside you, chews you up."


 * Marine: "We gotta get outta here."

Reaching the other end of the warehouses, the surviving Marines who joined the Chief and Arbiter hold position after clearing the area.


 * Arbiter: "Wretched parasite! Rise up and I will kill you! Again and again!"

Upstairs, a couple of Marines, one wielding the Flamethrower, tries to combat the Flood as well, but they soon die, leaving the flamethrower for the Chief or Arbiter to pick up as they head up there and down a hole in the floor into the office areas.


 * Cortana (Cortana Moment): "Chief. (connection drops) I can't tell you everything... it's not safe. The Gravemind... it knows I'm in the sys-(connection drops)."

''The Chief and Arbiter force their way through another wave of Flood, and find a marine huddling in a corner of the large room used for the Aid Station in the Storm on Voi, surrounded by three dead marines. The Marine is holding a pistol, and will occasionally aim it at his own head, then lower it and bury his face in his hands.


 * Traumatized Marine: "I... I didn't have a choice. (pause) The LT... the Sergeant... they were all infected! (Pause) I could see it crawling... SLIMING AROUND BENEATH THEIR SKIN! (sobs) (pause) A-and then they got up... s-started to talk! OH GOD! Their voices! Oh, God! No, make them stop! (pause) (His speech turns maniacal) I did them a favor... y-yeah that's it; I helped them. (sobs) (pause) Maybe... maybe I need to help myself..."

With no time to spare, the Chief and Arbiter continue on ahead to the lake bed.

Shadow of Intent
'The Flood. It has Evolved.'

''The Master Chief and Arbiter enter the lake bed of Voi where the Scarab was previously fought and destroyed.

Ship Master Rtas 'Vadum (COM): "Hail Humans, and take heed."

{Cutscene}

Ship Master Rtas 'Vadum (COM): "This is the carrier Shadow of Intent."

The Chief and the Arbiter pause to see three Elite-controlled CCS-class Battlecruisers fly in formation as an Assault Carrier slices overhead from Slipspace.

Ship Master Rtas 'Vadum (COM): "Clear this sector, while we deal with the Flood."

Major and 5 Special Operation Elites leap out of landed Orbital Insertion Pods ahead of the Chief and the Arbiter, fighting against the Flood.

{Gameplay}


 * Arbiter: "My brothers, I fear you bring bad news."


 * Major Domo Elite: "High Charity has fallen, become a dreaded hive!


 * Arbiter: "And The Fleet? Has quarantine been broken?"


 * Major Domo Elite: "A single ship broke through our line, and we gave chase."


 * Arbiter: "We had a fleet of hundreds!"


 * Major Domo Elite: "Alas brother, the Flood. It has evolved!"

The Chief, Arbiter, and Elites fight their way through the infestation and arrive at the crash site.


 * Commander Keyes (COM): "Chief, the Elites are looking for something. We didn't believe them when they told us."


 * Johnson (COM): "It's Cortana, Chief! She's on that ship! Find her - get her out!"

Once outside again, a couple of Separatists Phantoms arrive, dropping off more Elite reinforcements to combat the Flood.


 * Major Domo Elite or SpecOps Elite: "Hurry, Demon! We seek the same prize. But our Shipmaster will sacrifice all to stop the Flood."

''The Master Chief, the Arbiter, and the remaining Elites fight past dozens of Pure Forms, Combat Forms, and Infection Forms to the massive, burning hulk of the crashed Flood battle cruiser. Up an incline, an ominous hole resides in the ship's hull, leading to the interior.''


 * Arbiter: "We'll hold here. I will let nothing pass."

Master Chief drops in alone.

Infinite Devil Machine

 * Gravemind (Gravemind moment): "Do not be afraid. I am peace...I am salvation."



The Chief reaches into a large room after passing several dead Ultra Elites.


 * Gravemind (Gravemind moment): "I am a timeless chorus; join your voice with mine and sing victory everlasting!"

hTa_vJ-l4fY

{Cutscene}

''Inside the central chamber of the Flood-infested crashed cruiser. The Chief finds 'Cortana' in a small Covenant hand held memory unit.''


 * Cortana: "Chief!"


 * Master Chief: "Cortana?"


 * Cortana: "High Charity, the Prophets' holy city, it's on its way..."

Cortana's projection above the holographic unit flickers and then disappears.


 * Master Chief: "Cortana!"

''Suddenly, the humming of a Phantom's gravity drives are heard, and a Phantom appears over the open chamber. The Chief turns and readies his Assault Rifle at it while 343 Guilty Spark floats down from the Phantom, which continues to hover overhead.''


 * 343 Guilty Spark: (surprised) "Reclaimer!"

''A Flood Combat Form appears to the right, and 343 Guilty Spark turns and uses a powerful energy beam on it, destroying it in a single glancing hit. 343 Guilty Spark turns back to the Covenant device where Cortana supposedly is, and begins to interface it with a beam projected from his central eye.''


 * 343 Guilty Spark: "We must act quickly before your construct suffers any further trauma!"

The Chief grabs 343 Guilty Spark and pulls him away from Cortana's storage unit.


 * Master Chief: "Wait. Leave. Her. Alone."


 * 343 Guilty Spark: "If we do not take this device to a safe location, somewhere I can make repairs..."

343 Guilty Spark continues to try to project his multicolored energy beam into Cortana's storage unit.


 * Master Chief: "On Halo, you tried to kill Cortana. You tried to kill me".


 * 343 Guilty Spark: "Protocol dictated my response! She had the Activation Index and you were going to destroy my installation. You did destroy my installation. Now, I only have one function: to help you, Reclaimer, as I always should have done."

''The Master Chief stares wordlessly at 343 Guilty Spark, then slightly motions with Cortana's storage device. 343 Guilty Spark takes Cortana's device away, shooting his beam into it, while the Phantom projects a Gravity Lift. 343 Guilty Spark enters it first and the Master Chief reluctantly follows.''

''The view cuts to an aerial one over the whole town of Voi at a high altitude. Clouds completely obscure the surface of Earth, but part of the crashed Flood-controlled battle cruiser is visible in the distance. The Phantom flies away from the surface while two CCS-class Battle cruisers of the Sangheilian Fleet "Glass" the town of Voi with plasma beams.''

''The view then cuts to an aerial one above the Forerunner Portal. Its 'wings' are open and blue energy streams from their tips to the open Slip space portal drifting ominously above the construct. The scene is quiet, and the moon is in the background. Fighting on Earth has ceased, and the Second Battle of Earth has ended with the departure of the Prophet of Truth's fleet through the Portal hours earlier. Four vessels of the Sangheili Fleet are gathered above the Portal, and 343 Guilty Spark's Phantom arches to the largest of them: the assault carrier Shadow of Intent.''

''Inside the bridge of the Elite-controlled command vessel, the Assault Carrier Shadow of Intent. Elites and humans are gathered around a long holographic table, with Ship Master Rtas 'Vadum floating on a gravity throne at one end with his Elite attendants, Master Chief and the Arbiter in the middle, and Fleet Admiral Hood and Commander Miranda Keyes at the far side of the table. All are silent except 343 Guilty Spark, who is bobbing at the center of the table and interfacing with Cortana's memory unit with his projector beam.''


 * Rtas 'Vadum: "Will it live, Oracle? Can it be saved?"


 * 343 Guilty Spark: "Uncertain. This storage device has suffered considerable trauma. Its matrices are highly unstable."

343 Guilty Spark glances at 'Vadum and Lord Hood


 * Lord Hood: 'Perhaps one of our technicians-"


 * Rtas 'Vadum: "That will not be necessary."

Coincidentally, the storage device works again, and a holographic projection of Cortana springs up.


 * Cortana: "Chief!"


 * 343 Guilty Spark: "Success!"


 * Cortana: "High Charity...the Prophets' Holy City, is on its way to Earth, with an army of Flood. I can't tell you everything. It's not safe. The Gravemind...it knows I'm in the system."

Cortana's image flickers, and the Chief turns to Rtas 'Vadum.


 * Master Chief: "It's just a message."


 * Ship Master Rtas 'Vadum: "Let it play."

343 Guilty Spark jolts the device with another beam.


 * Cortana: "But it doesn't know about the Portal, where it leads. On the other side, there's a solution; a way to stop the Flood, without firing the remaining Halo rings-"

''Suddenly, Cortana's skin lights with lightning and she gasps in sudden pain and collapses onto the 'floor'."


 * Cortana: "Hurry, Chief... the Ark...there isn't much time."

Cortana's recording ends, she is left staring with desperation at the chief.


 * 343 Guilty Spark: "I'm so sorry..."


 * Rtas 'Vadum(Leaning back in his seat): "No matter, Oracle. We've heard enough. Our fight is through the Portal, with the Brutes and the bastard Truth!"

Special Operations Elites around the room raise their forearms and roar in agreement.


 * Lord Hood(Wearily): "Fine. We'll remain here...hold out as long as we can."


 * Ship Master Rtas 'Vadum: "Did you not hear? Your world is doomed." (Descends from his seat.) "A Flood army, a Gravemind, has you in its sights! You barely survived a small contamination."


 * Lord Hood: "And you, Ship Master, just glassed half a continent! Maybe the Flood isn't all I should be worried about..."


 * Ship Master Rtas 'Vadum: "One single Flood spore can destroy a species. Were it not for the Arbiter's council, I would have glassed your entire planet!"

Lord Hood angrily motions at 'Vadum, but Miranda Keyes places a hand on his shoulder.


 * Commander Keyes: "Sir, with respect, Cortana has a solution."


 * Lord Hood: (skeptical) "Cortana? Did you see her condition? How damaged she is?"

While Hood and Keyes argue, the Master Chief bends down and observes Cortana's pained collapsed paused figure.


 * Lord Hood: "She could be corrupted for all we know. Her "solution" could be a Flood trap!"


 * Commander Keyes: "We should go through the Portal, find out for sure."


 * Lord Hood: "What we should do Commander, is understand - clearly - that this is humanity's final stand - here - at Earth. We go, we risk everything; every last man, woman, and child. If we stand our ground, we might just have a chance."


 * Arbiter: "No. If your construct is wrong, then the Flood has already won."


 * Master Chief: "I'll find Cortana's solution. And I'll bring it back."


 * Lord Hood: "Earth...is all we have left. You trust Cortana that much?"


 * Master Chief: "Sir. Yes sir."


 * Lord Hood: "Then this is either the best decision you've ever made or the worst. Hell if it is, Chief? I doubt I'll live long enough to find out which."

Lord Hood turns, looks wordlessly at Miranda Keyes, and then exits the bridge.

Inside the Shadow of Intent'''s hangar bay, both the Elites and the UNSC are readying for battle; the battle through the Portal. While a Separatist Phantom drifts into the hangar on the far side, two M12 Warthog LRVs race to the loading elevator, drawing near a group of Marines clustered around some UNSC crates. At uneasy rest opposing the Marines are a Major Elite sitting on a Ghost and a few SpecOps Elites. The Major Elite's Particle Beam Rifle is resting on the floor. Sergeant Major Johnson, with his arm full with 'stolen' Covenant Carbines brushes past the wordless Elites, scooping to pick up the Major Elite's rifle. The Elites rise challengingly around Johnson.''

''Nearby, a pair of ODSTs are joking with each other as the Arbiter passes by, with an acquired M41 Rocket Launcher over his shoulder and carried a Missile Pod underhand. The ODSTs and a pair of nearby Marines observe the Arbiter in half-awe, half-disappointment over the loss of their heavy weapons, when 343 Guilty Spark drifts through the Marines in tow behind the Arbiter, leaving a Marine speechless. Johnson re-joins the Marines, beginning to hand out Carbines, the scene cuts to the fore of the hangar, where a Pelican Dropship lays before the hangar's energy field.'' ''The Chief and Miranda Keyes stand at attention before Lord Hood, who looks at them grimly from the rear of the Pelican as the troop bay door shuts and the Pelican takes off. Keyes glances at the Chief wordlessly, and the two leave, going off to their own businesses.''

Hood's Pelican arcs away from the gathered Sangheilian Fleet as the Shadow of Intent powers its engines and thrusts into the Portal, followed by eight Cruisers, a Carrier, the UNSC Frigates Forward Unto Dawn and Aegis Fate.

Normal Difficulty Walkthrough
At the beginning just backtrack your footsteps to where you fought the Hunters on the previous level Note: As you are walking back you can check between a truck and a crate to find a dead Brute Chieftain, with a 100% charge Gravity Hammer next to him take it if you do not like the Shotgun, otherwise exchange your BR for a Shotgun. Position yourself behind the sandbags with your Shotgun/Gravity Hammer out. Make sure to throw 2 Fragmentation Grenades down the ramp when the Flood shows up. If you look at the top of the building to the right with your scope right before you enter the city you will see a flood combat form come up to the edge and jump to the building on your left, if you shoot him right before he jumps he will throw a skull and it will land on the ground. Just mow down the Brute Combat Forms first then the Human Combat Forms. If the two Marines behind the sandbags are alive, good job. Go into the building and get your Assault Rifle out and you'll see a Marine run from a horde of Infection Forms. Shoot the one at the ground first then shoot the ones on him. Shoot a full reticule length away from him that way you don't shoot him.

When that's said and done, hop down with your Shotgun/Gravity Hammer and mow down any Flood coming near the Marines. The Infection Forms aren't much of a threat if there isn't something to distract you. Go crazy with the weapon as there is a large amount of ammo around. Head across the factory saving any Marines you can and killing all the Flood. When you see an area that looks clear, think again. Get out your Shotgun/Gravity Hammer. It's probably low on ammo by now, so take out whatever Flood you can then switch back to the Assault Rifle. When everything is dead, exchange your Shotgun for a Battle Rifle and do not pick up the Flamethrower from the corpses( if you attempt to burn the Flood they will not die right away and will charge you and kill you). If you have a Gravity Hammer do not get rid of it as you will need it. If any Marines survived they tend to get stuck and do not proceed to the next area, if you wish for them to keep fighting with you may need to give them a bit of a push and eventually they will start moving under their own steam (bear in mind it appears you can only take 5 marines to the next section).

Proceed through the only you can go and you'll be in a room of twists and bends. This is where the Gravity Hammer comes in handy. Go around the bend first and hammer them all to hell. When they're all dead proceed to a room with a scared Marine. It kind of reminds you of the one from Halo: Combat Evolved doesn't it? He won't do anything but say things of how his squad died. If you want whack him or just leave. You'll be outside and you'll get a cut scene of the Shadow of Intent dropping a few Elites. Help them out if you can, but they'll probably get killed then infected by the Flood. It is possible to kill the majority of the flood combat forms with a BR before triggering the cut scene if you stand on the catwalk to the left immediately out of the door that leads to the wide open area ensuring that the Elites have no immediate threats. You can also skip the cutscene, and watch it play out in real time, giving you time to catch up with your elites. Go forward and turn left after the 'tunnel'. There should be a broken elevator, go strait near the elevator and beyond that are 2 Plasma Rifles and an energy sword. There is a gap between you and the weapons so jump. Right now you should have an AR and a close range weapon. Swap the close range weapon for the Energy Sword as the Gravity Hammer has splash damage and you will harm elites. Swap the AR for the plasma rifles it doesn't really matter. Clean house with whatever you have left of the Flamethrower. If you don't like the energy sword take a shotgun from a flood combat form. Replace the close range weapon and proceed. When you see a ramp, I suggest you hang back a bit. Just literally run forward a bit and then run backwards so the Flood that jump out of the crater won't be on your 12 and 6. Wait until they get close so you can one-shot them with your Shotgun or melee with the energy sword, you don't want to all of it.

When all of the Flood are dead, go up the ramp and into the factory. To the left (where the ghosts were on the storm) are a bunch of AR's take one and go. If you have a Deployable Cover, drop it. It's a long hallway and if you just sit behind it, the ones with the guns are no threat. Stick a Combat Form in a group with a Plasma Grenade, and you should disperse most of them. There is a regenerator at the end by a dead marine. Use it and kill everyone with melee or the energy sword. You are practically invincible with it. When they're dealt with proceed forward to the spot where you found the .50 cal gunner on the last level. Get to the upper level and, with your shotgun, gun them all down. If one of them has a Needler, take it out quickly. They surprisingly have good aim. Before going outside, go into the building, same as if you were to open the door on the storm. There is a full flamethrower. When you go outside, you'll run into a new Flood form, known as the Pure Form. In it's first stage, the Stalker form, it can do nothing but run around, so it'll evolve into a ranged form, or a tank Form if you give it the time. Throw a frag grenade then one Shotgun should do it good. Or you can shoot them with the flame thrower. After that, the Elites finally show up to help. These are Assault Elites. Anyway, quickly get to the turret but beside the turret is a trip mine. Lay it far away down as it will kill you if you lay it close. Get on the turret and kill everyone. When it runs out of ammo let the Elites take care of the rest. Eventually you should be able to see 2 ranged forms bombarding you, obviously you should take them out. Maybe throw a grenade or just run in like stupid, 2-3 well places shots will take 'em down. When the crashed ship comes into view, just run to it, don't worry about the Elites or the Arbiter, they won't come anyway. When you're inside, DON'T SHOOT THOSE SPORE PODS! They spawn approximately 25-30 infection forms per sack. Plus, if you look closely at the dead ultra elites, you will see that some of them are the Shipmaster. As long as you don't shoot them, you won't face any opposition inside. Just pick up Cortana and watch the cutscene.

Suicidal Marine
Shortly after you get the Flamethrower, there will be a Marine in the corner talking to himself about his squad's infection by the Flood, and how he just "did them a favor." After this, he says something about how he should do himself a favor too, and points his gun at his head, seemingly about to kill himself, although he alternates between this and putting his gun down and shaking. It should also be noted that he sometimes will not have his gun out, and instead be pointing his empty hand at his head.

Trivia

 * This was the first and only known time the flood have been on Earth.
 * If you escape the level and walk towards the the giant container farthest from the level, you can walk into it and see a Brute arm lying on the ground.
 * When you encounter the Marines in the loading ramp area in the beginning of the level, it is in fact possible to save all of them except one, who is scripted to mutate into a Flood Combat Form. However, this is extremely difficult, and fairly impossible on higher difficulties.
 * The Marine that is scripted to be infected is not always the Sergeant.
 * To get some easy Meta-Game points, put on the Catch Skull. The Flood don't throw grenades but your Elite allies do. But watch out for friendly fire.
 * Inside the factory, there are five Marines total, all of whom can be saved. Of these five, however, the first one is being blitzed by an outsized number of Infection Forms, despite this, he can be easily saved by spraying wildly at the infection forms with either an SMG or an assault rifle another method is to take one swing with a Gravity Hammer at him. If the infection forms latch onto the marine, don't be scared to shoot the marine a little (about a quarter magazine), that will clear off most of the forms. The next two marines are defending some sandbag fortifications from a large number of Combat Forms, and the last two, including a Shotgun-wielding Reynolds or Stacker, are under attack from an equally large number of combat forms out in the open. Needless to say, it is extremely difficult to save them all, let alone a few. A good tactic is to quickly jump into the battle, sticking as many enemies as possible, and then swap a close range weapon (shotgun) with the stricken Marine and then use your Hammer to fight your way to the other group of Marines. Marines with Shotguns are extremely effective against Flood.
 * An easy way to save the five marines in the factory is to use the Gravity hammer that can be found at the start of the level.
 * It is possible to save the first Marine you encounter upon entering the facility. One way is to throw a frag grenade right behind the Marine (you must be fast). Almost every time you do this, the grenade will kill most of the Infection Forms and any on the Marine himself, leaving you to kill anymore Infection Forms left. However, turning on the Cowbell Skull would cause more serious damage to the Marine and result in his death.
 * At the start of the level just past the area with the SAM (Surface-to-Air-Missile) you can see what appears to be an image of a demon's head, if you look right when you should turn left, on some Covenant wreckage.
 * Often, the suicidal Marine will "change race", that is, one play through he will be white, and the other play through he will be black. This happens to all marines, unless its a main character such as Johnson, Stacker, etc.
 * If you save the Marine that is being chased by the Flood (most likely with a Shotgun) even if you shoot him by accident he will whine about friendly fire even though you saved his life.
 * The Suicidal Marine bears a striking resemblance to the Crazed Marine in the Halo: Combat Evolved level 343 Guilty Spark that shoots you (thinking that you may be Flood-controlled). It should be noted that the player comes across the Crazed Marine in the first level you fight the Flood and that you come across the Suicidal Marine in the first level you fight the Flood in Halo 3.
 * At the very beginning, where it says "It followed me home", walk forward until you see the large crack separating the land. If you zoom in, you will see 2 Marines, one with an SMG and one with a Pistol running. They will be followed by 4 Flood Combat Forms. If the Marines survive this wave, 6 more will come. Its fun to see how Marines fare against the Flood. Amazingly, in some cases they will survive this attack. If they do, they will run back the way they came. But if they lose, the surviving Flood will either stay where they stand, or they will run back to where they came from. You can help them with Grenades and your Battle Rifle but they will most likely die when they get ambushed by Flood up ahead.
 * It is possible to let the Marines whom you saved in the first half (if any) follow you for the rest of the level. Just walk halfway through the catwalk (Where the dead flamethrower-wielding Marine is. It leads to the room of the first Cortana transmission.) so that the AI makes the Arbiter follow suit. Then, push a Marine to the first few steps of the stairs. If done correctly, the Marine will walk all the way across the catwalk just like the Arbiter. Do this to the other Marine(s) (optional). You then have to proceed by going THROUGH THE HOLE. Don't jump through or break any of the windows! Or the AI will make some, if not most, of them attempt to run directly through the windows, and since the windows have small ledges, they won't be able to get out. So jump through the hole and push your Marines through the doorway the Arbiter passed through. (NOTE: This is the room UNDER the hole, the one with Medical crates.) If done correctly, the Marines should move through the other room to get to the large room with the 2 Field Armories, and follow you for the rest of the level, even fighting the Flood alongside the Elite reinforcements.
 * When you first encounter your Elite allies there is an elevator where the Elites are (you may have used it in The Storm to get on the Scarab) and at the top of the elevator are two plasma rifles and a fully-charged Energy Sword.
 * This level, and the level 343 Guilty Spark, are the only levels in the Halo series where Marines aid you in fighting against the Flood. (Though the level The Covenant does feature some combat sequences where the Marines or ODSTs assist you in combating the Flood).
 * When Lord Hood accuses the Ship Master of glassing half the continent of Africa, he is hyperbolically saying this in order to emphasize his disgust in the actions taken it glassing the area. In fact, the glassing of half the continent is impossible, for Mount Kilimanjaro can be seen unscathed in the post game credits; also, the memorial cinematic is set in Kenya which would coincidentally lie within the "half the continent" supposedly glassed.
 * During the part where the two Phantoms drop off Elite reinforcements to assist, the Elites that are dropped from the second Phantom (the one further up ahead, nearer to the crashed cruiser) can be saved if you reach there in time, otherwise they will die fighting the Flood, near a Gravity Hammer equipped-Brute corpse.
 * If you melee the Suicidal Marine, (depending whether if he survives) he will stop crying and may follow you through the rest of the level.
 * On rare occasions, when you reach the Suicidal Marine, he will be wearing a different uniform. Example: Standard Marine uniform or Specialist uniform.
 * While in the Covenant Cruiser, if you melee the dead bodies of the Elites down to the first biomass room and shoot a sac to infect them, after they are infected, one of the Flood Elite's bodies cannot be destroyed when up and moving, but can when not Infected or fighting. This is also a strange, but wonderful way to get points in the Meta-Game because it can be Infected an unlimited amount of times.
 * At the first checkpoint, you will hear Marines communicating over the radio. One of them says, "We're surrounded, Sergeant."  This is the same line spoken by Captain Keyes in Halo: Combat Evolved during the cutscene introducing the Flood.
 * Even if Lord Hood says that humanity's last stand is at Earth, the UNSC still has other planets that aren't glassed, like Sigma Octanus IV.
 * All of the Elites in the game are equipped with an Energy Sword as their secondary weapon. But oddly, they will never use it, save when their shields are drained and only have a bit of health left, (likely to be killed at that point) or when accidentally stuck by another Elite throwing a Plasma Grenade.
 * Despite seeing Johnson and the Arbiter exchanging weapons with the Elites and Marines during the ending cutscene, you never do see either side actually appear with the other's weaponry (with the exception of the Arbiter during Cortana).
 * In the second outdoor area, if you go into Theater Mode and watch the Elites dropped off by the Phantom up ahead, they will sometimes run up the ramp, and leap down the hole leading into the bowels of the ship. However, you never see any Spec-Ops Elites, or even their corpses in the ship.
 * Inside of the ship, among the fallen Elite, you can find an Elite with a helmet that is crossed between a Combat and Assault helmet. Occasionally, when infected the bodies will split and you will get two infected Elites, other times they will stay combined.
 * At the first checkpoint, the marines on the radio that says, "We're surrounded, Sergeant." is in fact Gus Sorola, the voice actor of Private Simmons from the web series, Red vs. Blue.
 * This is the only level in Halo 3 that takes place during night time.
 * It should be noted that the layout of the factory portion is nearly the same as the layout in The Storm, except the player is going in the opposite direction. This is similar to Two Betrayals.
 * During the final cutscene, the Elites lounging inside the Shadow of Intent stood up when Johnson walks by with numerous Covenant weapons; they may be doing this in surprise, disgust, or even honor.
 * On top of the Flood ship there is what appears to be a distorted demon face, but in actuality, it is just a texture that has two mirrored sides.
 * All of the Elite corpses in the crashed Covenant ship are the corpses of the Rtas Vadum eventhough he never dies in the story. You can tell it is his corpse because all of them have two missing mandibles.
 * It is possible to fight Flood Combat Forms inside the crashed ship. If you melee the Elite corpses down the hole and shoot the Flood bio-mass walls, the Infection Forms that emerge will take over the corpses of the Elites and will attempt to kill you.
 * This is the 1st Halo 3 level where you encounter the Flood, and the first in the series you encounter the Pure Forms and Brute Combat Forms.
 * This is the only level in Halo 3 where you encounter live Special Operations Elites.

Images
 Image:Floodgate1.jpg|The Shadow Of Intent leaves Earth via The Portal Image:Floodgate2.jpg|Lord Hood's dropship leaves The Shadow Of Intent Image:1214642228 Demon.jpg|the demon's face on covenant wreckage 