Halo Alpha
Halo Alpha


Looking for 343 Guilty Spark, the Monitor of Installations 04 and 04B?

Creep through a swamp to meet the only enemy the Covenant fear.

343 Guilty Spark is the sixth campaign level of Halo: Combat Evolved.

This level takes place on Installation 04, in a Flood Containment Facility. The first chapter of the level is set in a swamp and the second chapter, "The Flood" is set in the Alpha Halo containment facility. The third chapter is outside the containment facility. In this chapter, John-117 is dropped from Echo 419 to search for Captain Jacob Keyes who has been out of contact for over 12 hours. Soon, John-117 stumbles upon a structure and ventures within it, only to find out that the Marines accompanying the Captain have been slaughtered by an unknown force. After realizing the fate of the Marines, John fights his way out to the swamp and encounters a questionable ally.


Well Enough Alone[]

{Original Cutscene} {Anniversary Cutscene}

Camera flies over a group of Kig-Yar and Unggoy running through a swamp, panicky and obviously in retreat. As it pans over them, the player sees through the fog and rain the outline of a dropship, which further materializes as the camera draws closer.

  • Carol Rawley (COM): "The last transmission from the Captain's dropship was from this area. That was over twelve hours ago. When you locate Captain Keyes, radio in, and I'll come pick you up."


In certain parts of the level, the player can hear a radio transmission coming from a crashed human dropship and a Covenant communications terminal. As it repeats, it seems that this is some sort of distress beacon. Static pervades the transmission, and the signal fades in and out of clarity.

  • Dropship Victor 933's Pilot: "Dropship Victor 933-(static)-Pillar of Autumn-(static)-need assistance. We are under att-(static)-attack by some new kind of hostile-(static)-isn't Covenant. (Static) Captain Keyes has been captured by hostiles. (static) -dug in at a large structure in a swamp-(static)-We need to pull out. Please-(static)-I will set this message to repeat at-(static)-regular intervals. Dropship Victor 933, clear."

John-117 quickly finds the crashed dropship sending the message. There are weapons and supplies piled nearby, but no signs of life. He passes by a crashed Covenant Spirit and deals with a small group of Unggoy and Kig-yar, and crosses a log bridge. As he moves across the bridge, he sees several shadowy figures running around on the top of the cliff to the right. Also, his motion tracker shows seemingly friendly units in the swamp not too far from his location, but they suddenly disappear off radar.

When he reaches the other side, he hears Assault Rifle fire nearby. He investigates and sees a mob of Unggoy and Kig-yar fleeing from an A-shaped structure. A frag grenade explosion throws a Shade turret around. The fleeing Covenant attack him out of fear.

John-117, thinking Marines are attacking the Covenant, hurries to the entrance, but finds no one there. A lift arrives for him. He takes the lift down into the depths of the structure.

John-117 passes through several large rooms and many smaller ones inside the structure, filled with Unggoy, Kig-Yar, empty Shade turrets, discarded weapons, and dead bodies - both Marine and Covenant. In some rooms, Kig-Yar and Unggoy gather at the doorways as if expecting an attack. In one room, John discovers a strange green-yellow substance falling from the ceiling.

As John-117 comes into an area blasted with gunfire and scorch marks, there is the sound of shattering glass. A lone Marine sits leaning against a wall, Pistol pointed at you. He shoots at John if he comes too close, while screaming at the top of his lungs the following phrases. He also fiddles around with his pistol a lot, checking to see if the magazine is full.

AWOL Marine:

  • "Stay back! Stay back, you're not turning me into one of those things!"
  • "I'll blow your brains out! Get away from me!"
  • "GAAAAAHH! AAAAAAHH! Don't touch me, you freaks, I won't be like you, I'll die first!"
  • "Find your own hiding place, the monsters are everywhere!"
  • "Play dead! That's what I did... played dead. They took the live ones... oh God, I can still hear them!"
  • (Sobbing) "Monsters..."
  • "Ahhhhhh! Ahhhhaaahhh..."
  • "Sarge? Mendoza? Bisenti? Oh, God... the things took them, oh God, I can still hear them... (mumbles and cries) They're gone! Get it? GONE!"
  • "They won't get me! Oh God... oh God I don't want to be like them, please, please no, nooo..."

John-117 leaves him, and finds a way to the second floor. An Assault Rifle lies on the ground, pointing like an arrow towards the entrance of a room marked with ominous red Forerunner glyphs. The door appears to have been forced open. John goes in, passes a dead Marine, and walks down a ramp.

As you come down one of two ramps on either side of a door which has been recently opened by a UNSC spoofer.

{Original Cutscene} {Anniversary Cutscene}

John-117 approaches the door cautiously and listens for any movement inside. Just as he was going to type a command into the spoofer, there is a noise behind him. He turns around, gun ready to shoot, but sees nothing. After a moment, he turns back to the door, places his gun on his shoulder and opens the door. When it opens, a dead Marine falls into his arms. He advances a few paces, places the body on the floor gently while making sure nobody follows him through. He sweeps his Assault Rifle about the room. The floor is covered in blood. Discarded UNSC weapons lie all about. John-117 also notices a helmet lying on the floor, and, crouching, moves swiftly towards it. Once he's there, he surveys the room one more time, places his rifle on the floor, and picks up the helmet. The name JENKINS is stamped across it. There is a large, jagged hole punched through the top of it. John-117 shakes his head. He then examines the helmet more closely and notices that the Helmet recorder, near the HUD, is still intact. He retrieves the Recorder Chip and inserts it into a socket in his helmet (where Cortana was previously stored).

Recording starts playing:

Open Record View (2552.5.27.5:52:56 L).

Pvt. Jenkins, Wallace A.


Helmet cam view (night vision enabled). A Marine (Jenkins) looks around the inside of Dropship V-933. There are several other Marines seated in the dropship with him. Johnson's favorite music (flip music) blares over the cabin speakers.

  • Staff Sergeant Avery Johnson: "Watch your mouth, son. This "stuff" is your history. It should remind you grunts what we're fightin' to protect."
  • Private Manuel Mendoza: "Hey... if the Covenant wanna wipe out this particular part of my history, that's fine by me."
  • Private Bisenti: "Yeah... better it than us."
  • Staff Sergeant Avery Junior Johnson: "You ask 'em real nice next time you see 'em, Bisenti. I'm sure they'll be happy to oblige."
  • Pelican Dropship Pilot (COM): "LZ looks clear! I'm bringing us down!"
  • Staff Sergeant Avery Junior Johnson: "Go, go, go!"



The Squad advances through the swamp towards the same structure you are in now.

  • Staff Sergeant Avery Junior Johnson: "Stay close, Jenkins!"

They reach the entrance and sweep their weapons across it, wary.

  • Staff Sergeant Avery Junior Johnson: "Mendoza! Move it up!"

Mendoza advances in a crouch, gun at the ready.

  • Staff Sergeant Avery Junior Johnson: (to Jenkins) "Wait here for the Captain and his squad, and get your ass inside."
  • Staff Sergeant Avery Junior Johnson: "Okay, let's move!"

The team heads into the structure.



The squad stands around a Sangheili carcass, the chest is torn wide open. Private Kappus is examining a similar carcass on the left hand side of the screen.

  • Private Kappus: "--which is weird, right? I mean... look at it." (Prods the Sangheili with his foot.) "Something... scrambled the insides."
  • Staff Sergeant Avery Junior Johnson: "What's that? Plasma scarring?"
  • Private Kappus: "Yeah... I dunno. Maybe there was an accident. You know, friendly fire or something?"

Captain Keyes approaches the squad.

  • Staff Sergeant Avery Junior Johnson: "Looks like a Covenant patrol. Badass Elite units, all KIA."
  • Captain Jacob Keyes: "Real pretty. Friend of yours?"
  • Private Kappus: (sounds slightly apprehensive) "Nah, we just met."



The squad, along with Captain Jacob Keyes and his own squad, stand outside a locked door - the one you have just come through.

  • Captain Jacob Keyes: "Right. Well, let's get this door open."
  • Private Kappus: "I'll try, sir. But it looks like these Covenant worked pretty hard to lock it down."
  • Captain Jacob Keyes: (impatiently) "Just do it, son."
  • Private Kappus: "Yes, sir."

Kappus removes a Spoofer from his pocket and sticks it to the door. He punches a few keys, and the door opens. He waves the squad through. Bisenti takes point through the door, Jenkins close behind him, and the rest of the squad fans out around him. An odd rumbling sound is heard.

  • Private Manuel Mendoza: "I've got a bad feeling about this..."
  • Staff Sergeant Avery Junior Johnson: "Boy, you always got a bad feelin' about something--"
  • Corporal Lovik (COM): "--Captain, Sarge (static) can you hear me?!"
  • Captain Jacob Keyes: "What's going on, soldier?"
  • Corporal Lovik (COM): (panicked) "We've got contacts...lots of 'em...but they're not Covenant...they're just tearing through us...what the?!...ooooohhh...nooooo!!" (Flood noises can be heard in background)
  • Staff Sergeant Avery Junior Johnson: "Corporal? Do you copy, over?"

No response.

  • Staff Sergeant Avery Junior Johnson: "Mendoza, get your ass back up to Second Squad's position, and find out what the hell is goin' on."
  • Private Manuel Mendoza: "But, si--"
  • Staff Sergeant Avery Junior Johnson: "I don't have time for your lip, soldier! I gave you an order!"

The same noise that John-117 heard before entering the room is heard.

  • Private Kappus: "Sarge! Listen!"

The odd hissing noise grows louder and louder.

Everyone scans the room, trying to find the source of the strange sounds.

  • Private Bisenti: "What is that?"
  • Sergeant Johnson: "Where's that coming from, Mendoza?"
  • Private Mendoza: "Everywhere... I don't--there! ¡Mira!"

Mendoza points to a nearby door, which has just exploded outwards. Small squid-like creatures swarm from it.

  • Private Riley: "Ahh... augh! Get it off! Get it off-- augh!"

Riley lies on the ground, one of the Infection Forms attached to his chest. Kappus tries to pull it off him.

  • Private Kappus: "Hold still, hold still!"

Kappus pulls the creature off of Riley, who goes limp. Kappus struggles with the creature which is now trying to infect him.

  • Staff Sergeant Avery Junior Johnson: "Let 'em have it!"

The Marines and Captain Jacob Keyes open fire, to little effect. Infection Forms are now all around them.

  • Captain Jacob Keyes: "Sergeant, we're surrounded!"
  • Staff Sergeant Avery Junior Johnson: "God dammit, Jenkins! Fire your weapon!"
  • Private Mendoza: "There are too many, Sarge!"
  • Sergeant Johnson: "Don't even think about it, Marine!"
  • Private Mendoza: (Staggers for the door, several Infection Forms on his back.) "Yo, this is loco!"
  • Captain Jacob Keyes: (through clenched teeth) "Get back here, Marine! That's an order!"

The Marine squad is overtaken, still firing, while their blood sprays as Infection Forms continue to crawl onto them.

  • Staff Sergeant Avery Junior Johnson: "Jenkins!"

Several Infection Forms attack Jenkins and block his helmet cam. After a moment the screen blacks out. Words flash.

>Unexpected Halt X (WND/INCAP/KIA? Ref.a4 3d.3) (WND stands for Wounded, INCAP stands for Incapacitated, KIA stands for Killed in action; the question mark indicates the status is unknown.)

>End Record View (2552.5.27.6:39:23 L)

John-117 removes the chip from his helmet, shakes his head, and tosses the chip to the ground. The noises begin again. He stands quickly, gun ready.

  • NOTE: Even though Sergeant Johnson is attacked by Infection Forms, he survives because the Flood cannot infect him due to his alleged Boren's Syndrome (actually the side effects of his Spartan-I augmentation).
  • NOTE 2: The date listed on Jenkins' camera is incorrect. The events on Alpha Halo took place in September of 2552, not May.

The Flood[]


The door John-117 came through is now locked. Three doors holding dozens of Infection Forms break open one at a time, their inhabitants attacking him.

The entrance breaks open. Massive amounts of Infection Forms skitter inside, followed by unarmed Sangheili Combat Forms.

John-117 escapes the facility, encountering Flood forms and some Covenant infantry struggling to survive.

Scrn 036

John is about to be attacked by Infection Forms that broke quarantine in Containment Facility.

John-117 tries to take the elevator he entered with, but while he waits for it to come down, it suddenly falls down and crashes down to the bottom of the facility.

After some fighting, John-117 arrives at another elevator, but it goes deeper underground and Unggoy blood is seen painted on the elevator's shaft. At the bottom of the shaft, he's attacked by armed Combat Forms - both Sangheili and Human. This detour forces him to fight his way back up.

John-117 eventually sees two or three Marines armed with Shotguns or Assault Rifles fighting the Flood.

Although their weapons give them a distinct advantage, a single Infection Form or a single Combat Form attack can kill them.

If they survive, they hold their position inside the room.

As John-117 reaches the final elevator and rises to an exit from the structure.

  • Carol Rawley (COM): "This is Echo 419. Chief, is that you? I lost your signal when you disappeared inside the structure. What's going on down there? I'm tracking movement all over the place!"

John-117 reaches the top where a group of trapped Marines is holding out.

It is obvious they used a lot of ammo to escape, and it is all stacked in a pile. Most Marines hold Shotguns and Assault Rifles, one or two have Plasma Rifles.

Marines escape

Corporal Lovik and the survivors of the second squad attempting to escape the Flood-infested swamp.

  • Marine: "We could use your help, sir."
  • PFC Chips Dubbo: (Desperate and afraid) "Sir! Thank God you're here! We've been lost out here for hours. After we lost contact with the rest of the mission, we, we headed for the RV point, and then these....these things...they ambushed us. We've gotta get out of here!"
  • Carol Rawley (COM): "There's a large tower a few hundred meters from your current position. Find a way above the fog and foliage canopy and I can move in and pick you up."

The Marine squad eagerly follows John-117 outside, where the Flood close in from all sides. Some Marines are attacked by Infection Forms, and their allies are forced to shoot them. If you lead them, they all may survive, but this is rare. Corporal Lovik will most likely survive, being that he is a Corporal, has slightly higher health.

As John-117 comes near the tower Foehammer was speaking of, an odd blue object and a flotilla of floating robots descends from the mist. The robots begin to slice away at any nearby Flood, avoiding your Marines. After a few seconds of fighting around the base of the tower, the screen fades to white.

343 Guilty Spark[]

{Original Cutscene} {Anniversary Cutscene}

John-117 suddenly finds himself enveloped in a bright gold light, and then appears on top of one of the legs of the tower. The blue object hovers in front of him. John instinctively points his weapon at it.

John slowly lowers his Assault Rifle. Gunfire is still heard below, and bright beams slice through the dark swamp. John and the Monitor ignore the commotion.

  • 343 Guilty Spark: "Someone has released the Flood. My function is to prevent it from leaving this installation. But I require your assistance. Come. This way."

John-117 and the Monitor vanish in another series of gold flashes.

  • Carol Rawley (COM): "Chief, I've lost your signal! Where'd you go? Chief? Chief!"

Fades to black.

Level ends.


Icon Name Description Value
343 Guilty Spark (achievement)HTMCC AchievementArt 343-Guilty-Spark 343 Guilty Spark Complete 343 Guilty Spark. 25G (CEA)

10G (MCC)

HTMCC AchievementArt Bearly-Contained Bearly Contained Activate Terminal 6 on 343 Guilty Spark. 5G
Breaking Quarantine (achievement) Breaking Quarantine Escape the Forerunner facility in the level in 21 minutes or less (CEA only). 25G
HTMCC AchievementArt Circuit-Breaker Circuit Breaker Beat the par score on 343 Guilty Spark. 10G
HTMCC AchievementArt Get-Me-Out-of-Here Get Me Out of Here! Ride in a Pelican for several seconds on the level 343 Guilty Spark. 5G
HTMCC AchievementArt Lightning-in-a-Bottle Lightning in a Bottle Beat the par time on 343 Guilty Spark. 10G
HTMCC AchievementArt Skulltaker-Halo-CE-Recession Skulltaker Halo: CE: Recession Find and claim the Recession skull in remastered mode. 5G
This One’s for Jenkins! This One’s for Jenkins! Kill 50 Flood Combat Forms in the level on Heroic difficulty or harder (CEA only). 10G



Main article: Glitches
  • If the player plays in co-op and use the stay on Pelican glitch, then leave one player in the upper swamp and the other player walks along the tree trunk, then the player that is above can see the Flood up close and kill them easier.
  • When the Covenant run away from the structure early in the level, there are Assault Rifle shots coming from the structure. To see this fully, use the "Stay in Pelican Trick" to get to the higher level of the swamp. Walk towards the entrance and slide down. The player will see three MA5Bs floating in the air pointing at different angles, firing wildly for a few seconds before disappearing.
  • If the player looks closely at the dead Marine before John-117 lays him on the floor in the cutscene, the player can see that the Marine will blink about two to four times despite the fact that he's supposed to be dead.
  • If the player pushes the Shade turret in the way of Jenkins' scripted walk path prior to entering the structure beforehand, the player will get stuck in the spot where the turret was placed but continue his scripted movement while the rest of the squad moves ahead of him into the structure due to the fact that the recording takes place in exactly the same places that the player previously traveled. This is because the game doesn't "clear out" the room and return it to the state that it was in when Jenkins and his companions were in it.


  • During the Private Jenkins' helmet cam cutscene, when the Pelican dropship lands, the player can see a crashed Pelican in the background. It is odd that the Marines do not inspect the downed Pelican. Though, an explanation could be that V933 is one of the other Pelicans that landed to drop off troops for the mission but, probably crashed. In addition, John probably fast forwarded the recording before the player could see the squad inspect the crash site. Another sign of evidence supporting why the V933 is different from Johnson's Pelican would be that the voice of the repeating recording left by the pilot of V933 was male but, the voice of the pilot in the other dropship was female. One additional explanation would be that in the "Jenkins' recording" cutscene, Johnson orders several Marines to wait at the structure's entrance for when Captain Keyes and a "second squad" arrive. Another theory is that either Victor 933 was Second Squad's Pelican or Johnson's Pelican's wingmate.
  • It is impossible for V933 to be Johnson and Keyes' Pelican because the voice in the distress signal was male. However, in Halo: The Flood, the pilot of their Pelican was female. Therefore, the Pelican could have crashed when attempting to takeoff and was later attacked by the already escaped Flood since it was also stated that Johnson's squad found evidence of combat before they even arrived. In conclusion, it is more than likely that the V933 was attacked by the Flood before Johnson and Keyes even arrived and was later overlooked by them due to the possibility that the swamp's fog was probably thicker when they arrived.
  • The date on the timestamp of Private Jenkins' footage is May 27, 2552; months before the game actually takes place. This is due to the Private not calibrating his helmet cam's time.
  • During the ending cutscene, the Monitor can be seen flying around the tower as well as talking to John. Similar to the Shade turret glitch above, this is because the Monitor is in the level before the cutscene, but isn't removed when the cutscene starts.
  • After the player encounters the Crazed Marine, there is a Plasma Rifle laying on the ground. There was supposed to be a dead Sangheili beside him but oddly it only appears in Jenkins' recording despite that same Sangheili being encountered by John in Halo: The Flood as well. Another theory is that the Sangheili Warrior was infected by the Flood before John arrived on the scene.
  • Sometimes Sgt. Johnson will be in the surviving second squad, even though he escaped the structure by himself, according to the Halo Graphic Novel.
  • According to Halo: The Flood, Jenkins was the one who tried to run, instead of Mendoza. Also, it is unknown how Jenkins' helmet got damaged as according to the book, an Infection Form got Jenkins on the back.
  • It is odd that the dead Marine in the recording cutscene is still there, as the Flood infect anything they find. Of course, Bungie may have just put it there to increase the tense atmosphere that started at the beginning of the level. However, in the novel, he's been half-infected by the Flood.
  • In Jenkins' helmet cam, the Marines exit the Pelican from at least 10 feet off the ground.
  • Sometimes, after John-117 has left Dropship V933's crash site, the emergency distress call will start again prematurely, causing the message to overlap on itself.
  • The Spoofer which John-117 uses to open the door, only appears in the cut-scene and not during actual gameplay.
  • The dead marine who falls on John-117 has a hat on during the cutscene, though during gameplay he doesn't.
  • In the Anniversary version of Halo: Combat Evolved, there is a subtitle error on Foehammer's speech during the opening cutscene. After she said "That was over twelve hours ago," the subtitles displayed as "...and we've been unable to reestablish contact with the Captain or his team," but she never said that. Another subtitle error was after John-117 gets out of the Pelican and waits for some seconds, the subtitles will display as "Good luck sir." but again, Foehammer did not say that line.

Easter Eggs[]

Main article: Easter Eggs
  • At the very beginning of this mission, when you are still in the Pelican, immediately throw a plasma grenade. This allows you to stay within the aircraft. After a while, the pelican will "crash" and you will be able to walk around the top parts of the map. You can encounter a lone marine who is simply standing out there and will not follow you (although it is possible to attack him, in which he will respond). If you keep walking around, you slip down and see floating assault rifles shooting at the Covenant (at the area where the explosion occurs).
  • During the first chapter of the level, corpses will spawn in the swamp when you are at some point of the inside of the installation. Walk back outside before the Private Jenkins helmet cam cutscene, and bodies of Marines will be scattered through the lower level of the swamp. If the player can make it to the upper level of the swamp (around Mendoza and such), the player will find corpses of Covenant and Human Flood forms.
  • There is a hidden active camouflage in this level. After the player kills the Kig-Yar on the tree trunk that goes to the next part of the level, get onto the tree trunk. Once in the middle, the player must stop. Turn right. Jump down. There is a pipe leading up to a small ledge that is too high to jump to. There is a ramp. Go up it. Go as far back as the player can on the ledge, and inside a bush there is an Active Camouflage power-up.
  • Private Jenkins' chip says "Do Not Eat." However, it is only visible if the player opens the map with HMT and look at the Bitmaps tab.
  • If the player walks off the tree trunk and go left occasionally a Sangheili Combat Form will jot across the player's path. This occasionally varies in direction.
  • When the player sees the fallen Spirit dropship keep moving forward and advance to the fallen tree. Look up and use the pistol scope and the player will see a Flood Combat form. The Combat form can be shot and have pieces blown off, but it cannot be killed, as so not to spoil the surprise of the Flood.
  • This level has the Hidden Flood Combat Forms Easter egg.
  • This level makes several references to the movie Aliens, such as the banter between the marines witnessed by observing Jenkins' recording.


  • In the Halo 3 level, Floodgate, there is another Crazed Marine, though this one won't shoot at the player. Instead, he points a Magnum at his head occasionally, contemplating suicide. Some have rumored that there is also a crazed Marine in Halo 2 on the level Sacred Icon, who is hidden. [verification needed]
  • There was an idea for the Crazed Marine earlier in the development of this level in which he would stay alive, and when the player walked a distance away from him there was going to be a loud bang. If the player came back, you would find him dead on the floor. This was revealed by Joseph Staten on the Halo 3 Legendary Edition bonus disk.
  • The line "I have a bad feeling about this" is another Bungie homage to Aliens or Star Wars.
  • The swamps are covered by some kind of glowing plants. Similar plants may be seen in High Charity in Halo 2.
  • In the novel Halo: The Flood, John was claimed to have taken away the Crazed Marine's pistol and ordering him to calm down before returning the pistol to him. Although, he never followed the orders, both in the game and the novel.
  • Some point after the player watches Jenkins' recording, the player will come across three Marines that are struggling to fight off a horde of Flood. Those three Marines are actually noted to have existed in Halo: The Flood, stating that John was amazed to see that other rescue teams were actually still present inside of the facility. It is possible to save them from being killed, however, they will not follow you any further. Instead, they will run in circles, occasionally dropping to one knee for a moment, and repeat the phrases: "I'm not sticking around to get killed," "I'm gone, man," "I'm out of here," "You can't stop them," "Forget this," "Later, dude" and "This is suicide, man!"


  • The song playing during the Pelican ride with Sergeant Johnson and the Marines is titled Shreddin', from the game Marathon: Durandal as "flip music," another Bungie creation rather than their previously planned licensed song which was going to be "Paint it Black" by the Rolling Stones. Marty O'Donnell stated this on the Halo 3 Legendary Edition bonus disk.
  • This is one of three levels in the entire Halo trilogy where the player can see and use Needler magazines, the others being the Halo 2 multiplayer map Uplift, and the mission Quarantine Zone.
  • Flood do not reload and can somehow fire endlessly.
  • The swamp area in the end of the level was later reused for the map Backwash in Halo 2.
  • The Pelican, Victor 933, is stated in Halo: The Flood, to have been only one of the many UNSC forces sent to investigate the alleged "weapons cache," thus explaining the reason for the large numbers of human Combat Forms.
  • Playing the level on "Easy" is the only way to play the level according to events from Halo: The Flood, due to the fact that you can only obtain a shotgun at V933's crash site as mentioned in the book on "easy" where in comparison to higher difficulties the shotgun won't be encountered until the events that occur after the "Jenkins' recording" cutscene.
  • At the start of the level, the player can see multiple Flood Combat Forms (both previous Elites and Marines) running across the lower and upper regions of the swamp. They will appear as yellow blips on the player's radar, indicating they are allies. This is done to add mystery and suspense to the initial part of the mission.
    • Interestingly, if the player finds a way to avoid triggering the Flood Combat Forms (i.e., by doing the riding in the Pelican glitch), enters the facility, returns to the surface, and triggers the combat forms, they will now appear as red blips on the player's radar, indicating them as enemies. This further cements that this was done to add suspense and mystery.
  • A Flash Parody was made about this level, titled "TISAH: Flood," it features almost each notable aspect of this level. In the part where John-117 first makes contact with the Flood, a reference is made about the zombie series Resident Evil.
  • If the player were to examine the floor to the right of the unlocked containment door, the player can find the neural chip that John-117 tossed aside after the "last recording" cutscene. However, it will disappear as if it was a particle over a short period of time.
  • Before entering the unlocked Flood containment room, there is an object that resembles a vault or door of some type. Its purpose and function is completely unknown though, it is most likely another more advanced lock containing more Flood captives. In addition, on both sides of the "door" there are four mechanisms inserted into the walls. The four mechanisms are believed to be earlier versions of the Forerunner energy cells that appear in Halo 2 and Halo 3 though these variants are indestructible due to graphic limitations.
  • The dead Sangheili seen in the "recording" was specifically made for the cutscene due to it having its own file and model.
  • Before the player enters the installation in this level and choose to linger in the swamps, one can hear in the background Flood gurgles and howls. However, the player will not see any Flood Combat Forms roaming, just the noises can be heard.
  • This level is one of the few rare mission levels with both red team and blue team symbols. They can be found near the first Flood encounter area and at any similar areas In the levels.
  • Above the passageway to the first player encounter with the Flood, there are red team symbols. It can be assumed that the red symbols indicate potential danger ahead.
  • As the player moves inside the building, the player will see a Flood containment room blocked off by supply cases. Inside are dead Unggoy and Kig-Yar. They were probably there because the Flood couldn't infect them as they didn't have enough calcium, so they tossed them aside. There is also the possibility that the Kig-Yar encountered moments before finding the containment room barricaded the gored Unggoy and Kig-Yar to prevent the risk of them becoming infected or because they were showing signs of progression towards becoming Flood.
  • While the player tries to cut through the waves of Flood, the player may notice that sometimes a skull will fall out of a Human form's head. This is best demonstrated from close-range shotgun blasts. However, if the player melees the skull, it will disappear.
  • This is the only campaign level that starts with a number.
  • If the player returns to the elevator he/she entered the structure with after meeting the Flood, looking up to where the elevator is, the player can clearly observe that it is on fire and damaged. Activating it will result in the elevator debris falling down the shaft, and the Halo soundtrack Lament for Pvt. Jenkins will play again.
  • In Halo PC and Custom Edition, if the player opens the map in a modding program such as Halo map tools, goes to the cyborg biped, and makes the jump velocity (height) around 3, they will be able to re-access the area above, triggering a loading point. Along the way, if you haven't activated the elevator, you will find that the elevator is not a physical object, and you can go through it.
  • This is the final level of Halo: Combat Evolved in which Marines are seen alive (except for the non-canon Legendary ending on The Maw featuring Johnson and a Sangheili).
  • It should also be noted that once the player has passed the lone Marine, the player won't be able to get back to him once the player has discovered the Flood, unless you can force a shade turret halfway into the doorway of that room. The crazed marine will not be there, but there will be some combat forms.
  • There is a unique Flood infection form used for Jenkins recording cutscene, in the modding code it is called a "nopop" and is specifically designed not to pop in the cutscene.
  • Both the Sniper Rifle and Rocket Launcher can be found in the files of this level, including Ammo packs. However, there is no spawn point on the level for either weapon.
  • In one of the last rooms in the containment center before returning to the surface, there is a pile of Marine and Kig-Yar corpses sprawled across a dismantled pillar, with Needler rounds and Shotgun shells next to them. It is assumed that in a last ditch effort, the Marines and Kig-Yars likely formed an alliance against the Flood who were descending into the room. This is confirmed in Halo: The Flood, where it's described the corpses were far too mangled for the Flood to mutate into Combat Forms. Furthermore, given the Kig-Yar were armed with Needlers (they only utilize Plasma Pistols in Halo: CE), it's likely they took the weapons of fallen Sanghelli and Unggoy to help them in the fight against the Flood.
  • If the player blocks the door where you exit from the AWOL Marine room with a Shade Turret, he/she can enter the room again (after John-117 encounters the Flood the room is locked) using the shade turret after John-117 encounters the Flood. In the room there are a few Infection forms and combat forms. Also there will be the corpse of the Sangheili seen on Pvt. Jenkins helmet cam. The player MUST NOT skip the cutscene where John-117 views Pvt. Jenkins helm cam or else the corpse will not load. The corpse shows that the center of the Sangheili is ripped open. There are several other ripped-open bodies found around the room.
  • This level, along with The Library, are the only missions in Halo: Combat Evolved that does not feature any living Sangheili.
  • If you find a point in the swamp where you can dunk underwater, you can see all of the level below you.
  • On the Halo: Combat Evolved Anniversary version of the level, many elements of the old design are not present in the new graphics engine, such as the sound effects for the dripping Flood particles and the smeared Covenant blood on the elevator shaft.
  • This is the first level to feature the shotgun.
  • In Halo: Combat Evolved Anniversary, at the entrance to the Forerunner facility, when the Kig-Yar and Unggoy are running from the explosion, one can find an Unggoy Minor that has red armor, instead of the orange armor the proper Unggoy Minor would have. If one switches back to classic mode, it is actually a red Unggoy Major.
  • In the original cutscene detailing the discovery of the Flood, when Keyes appears, he is no longer wearing his Captain's uniform, having changed into a set of Marine fatigues. In the redone cutscene for Halo: Combat Evolved Anniversary however, Keyes still appears in his Captain's uniform instead.
  • Before heading into the large containment room previously sealed by the Covenant, it is possible to look inside that room through a window beyond the ramp at what appears to be a control or monitoring position. Unlike later, once inside the room, the first door on the left side remains intact. Jenkins' helmet, however, is visible from here.