Sierra 117

Were you looking for John-117, the protagonist of the Halo trilogy?

Sierra 117 is the second Campaign level of Halo 3. It is the first level to feature real game play, as opposed to the first level, Arrival, which is merely a cutscene and tutorial. This is also the first level to feature Cortana Moments.

Upon completing the level on the Normal, Heroic, or Legendary difficulties, the player will earn the "Landfall" achievement and 20 Gamerscore. Upon earning 15,000 points in Campaign Scoring, the player will be awarded with the Guerilla achievement and 10 Gamerscore.

Setting
This level takes place in a lush African jungle that lies on the southern slopes of Shira peak, as confirmed from the hexadecimal code of the Halo 3 Beta and physically confirmed in the Halo 3 E3 2007 Trailer and the short video subsequent Bungie Podcasts (Mawenzi peak can be seen slightly obscured to the right of Uhuru peak, both of which are part of the Kilimanjaro mountain.) The jungle is home to a Covenant Loyalist encampment, and hosts lush verdant forestry, rivers, rocky landscapes, waterfalls, and tunnels. It has been compared to "Off the Rock, Through the Bush, Nothing but Jackal" of Halo 2 ' s Delta Halo, although it isn't the same place, because Sierra 117 is on Earth and Delta Halo takes place on Installation 05.

Plot
Having been found by Johnson, his Marines, and the Arbiter Thel 'Vadam, the Master Chief is escorted through the jungle not knowing there is trouble ahead. Johnson has with him two squads of Marines, but after spotting a Covenant Phantom overhead he decides to split them in order to try and reach an evacuation point at the nearby river. The Master Chief, Thel 'Vadam and one squad head one way, following the stream, while Johnson and the other UNSC forces scale a waterfall and head another way. Bravo squad, apparently left behind by Johnson's team to guard the PZ, then breaks radio silence and is attacked by a Brute Chieftain.

The Chief encounters the previously patrolling Phantoms, which drop off Brutes and Grunts. After the battle, they receive notice from Johnson that they cannot get into contact with another Marine team, Bravo. Almost immediately after, the group comes across a stricken Marine held captive by a Brute on a log above them. The Brute beats the Marine, inquiring about an "Ark". After killing the inquisitive Brute, they are told that the rest of Bravo is dead, apparently pinned down by a Phantom and slaughtered by a Brute Chieftain. The Bravo team survivor, Gunnery Sergeant Reynolds, then joins the squad escorting the Master Chief.

By the time the Master Chief and Thel 'Vadam make it to the river for evacuation, the Pelicans at the evacuation point are already under attack by Covenant infantry and multiple Banshees. Johnson is seen using the Machine Gun Turret at the back of one of the Pelicans, and with combined fire the Covenant are momentarily pushed back. This does not offset the heavy damage taken and they make a fiery exit further down river as more Brute and Grunt reinforcements show up to kill Master Chief's squad. After pushing through the Covenant forces, the Chief and Thel 'Vadam are told over the COM that Johnson's Pelican has crash landed and shortly afterward come across him and his squad fleeing from the crash site, pursued by Brutes and Grunts. The Chieftain pulls his own Phantom out of the fight to regroup.

They desperately try to catch up with Johnson, killing many Grunts, Brutes, and Jackals. After coming across the crashed Pelican, they find Sniper Rifles and Battle Rifles and they discover over the Pelican's radio that there is no sign of the second Pelican. It is assumed to have crashed and sunk into the lake. Master Chief, Thel 'Vadam and the surviving Marines then find themselves in a thick jungle and have to fight past Jackals hiding in the trees and on the ground, with no sign of Johnson or his squad of marines.

They then reach a large dam where they see Johnson being taunted and kicked into a small building and held captive by a Brute Chieftain. It is implied that this is the same Chieftain that killed Bravo's men and pursued Johnson from his crash site. The area is also littered with Grunts and Jackals as well as half a dozen Brutes. With slow progress, the two heroes manage to fight their way through and around the dam and eventually take down the Brute Chieftain. They then rescue Johnson and the three surviving Marines from his squad. (Note: the Marines will not appear if you still have Marines from before)

Johnson calls in Pelican Kilo 023 piloted by Hocus to come and pick them up, but they are first engaged by two Phantoms which drop off hordes of Grunts and a few Brute Captains wielding Brute Shots and Spikers. Whilst the group engages the ground forces, the Pelican arrives and takes down the two Phantoms with missiles. Hocus then lands and evacuates the survivors and Johnson is seen patting the Chief on the shoulder in thanks before the Pelican flies off.

Walk It Off
Brutes on the prowl.

{Gameplay}

Sergeant Johnson: "First Squad, you're my scouts. Move out! Quiet as you can."

Co-op change: Sergeant Johnson: "First Squad, you're my scouts. Arbiter, watch the Chief's back. Move out! Quiet as you can."

(3-4 Players Co-op) First squad you're my scouts. As for you, just try not to wreck my planet. Move out quiet as you can.

If the Chief waits and hangs around.

Sergeant Johnson: "Let's get moving, Chief. Come on. I'll lead you out."

Sergeant Johnson: "Bravo Team, this is Johnson. We got him. Fall back to the extraction point. Over."

G. Sgt. Reynolds (COM): "Roger that. Reynolds out."

A Brute howls off in the distance.

Marine: "That sounded close."

Marine: "Yeah, too close."

Sergeant Reynolds (COM): "Johnson, you be advised. Hostiles are -{static}- on the move -{static}-. I've got eyes on a -{static}- Brute Pack -{static}-. Over."

Sergeant Johnson: "Say again, Gunny? You're breaking up."

There is the ominous whisper of gravitational drives as a Phantom flies overhead above the trees.

Marine: (whispers) "Sergeant Major, Phantom inbound."''

Sergeant Johnson: "We stick together, we're gonna get spotted. We'll split up, and meet back at the LZ. Chief, go with the Arbiter, head toward the river. Second Squad, you're with me."

Co-op change: Sergeant Johnson: "Chief, you and the Arbiter head toward the river."

''Johnson and Second Squad climb up the cliff by the water fall. The Master Chief and Thel 'Vadam lead First Squad. Thel 'Vadam leads the Chief up on some rocks around a pile of fallen logs, while First Squad waits to go straight over, pointing out a Brute Captain Major.''

Brute Captain: "Spread out, you whelps! Find them!"

Marine: (whispers) "Up ahead! Single Brute, plus backup!"

Marine: "He's got power armor, Chief!"

''First Squad engages the Brute and his Grunt subordinates along with the Master Chief and Thel 'Vadam. They regroup.''

Thel 'Vadam (Single Player Only): ''(To the Brute corpse) "The Prophets are liars, but you are fools to do their bidding!"

''A couple of Phantoms draw near, each deploying a squad of Grunts and Brutes, blocking the advance of the Master Chief and his allies. Eventually, they are cleared, and the Marines form up at a winking flare at an underground cave.''

Marine: "Those Brutes are tough. Grunts ain't no slouches either."

Thel 'Vadam: "The Grunts' new-found courage is but fear."

Reply in Co-op: Marine : "Maybe the Brutes put something in their tanks."

Or if there are no Marines left:

Thel 'Vadam: "When we are victorious, all who serve the Prophets will be punished."

''After advancing through the caves, a massive forested expanse is found: the "Grunt Camp". Sleeping Grunts litter the first half while a few Brutes, Jackals, and other Grunts patrol the far hills.''

Marine: "Sleepers! Take 'em out, nice and quiet! {On Heroic or Legendary} Jackals, on the ridge! Stay low; looks like they've got Carbines."

When you are spotted by Covenant:

Marine: {On Heroic or Legendary} I hate it when I'm right!

After the team clears the Covenant Camp.

Sergeant Johnson (COM): "Pelicans are en route, Chief, but I can't reach Bravo. If you find 'em, get 'em to the extraction point."

Beyond the encampment, a Brute Captain is torturing a Sergeant Reynolds on a log {It is possible and optional to save the Marine by killing or distracting the Brute before he kills him}.

Brute Captain: "Tell me its location!"

Sergeant Reynolds: "Kiss...my...ass."

''If the Sergeant is not saved, the Brute Captain breaks his spine and throws him down, noticing the Master Chief and 'Vadam. If he is saved, Reynolds jumps down from the log, grabbing a nearby fallen Assault Rifle and joining the Master Chief and 'Vadam in their fight.''

Sergeant Reynolds: "Brute Chieftain. Phantom. Pinned us down... killed my men."

First Squad continues on until they reach another cave.

Thel 'Vadam: "The river, hurry!"

''The minor UNSC force continues forward, towards further caves and pushing towards the river, where Johnson has established an extraction point for Second Squad. They head down a steep slope for some underground caves that lead to the river.''

Cortana (Cortana Moment): "Could you sacrifice me to complete your mission? Could you watch me die?"

Marine: (looks back) "Sir, you okay?"

Marine: (concerned) "Your vitals just pinged KIA."

Marine: (looks back, on Legendary with IWHBYD) "Uh, you're a chick, right?"

Charlie Foxtrot
Hostile air inbound.

''Second Squad leaves the caves; the river is around the next bend. Three Marine corpses are scattered on the ground, with BR55HB SR Battle Rifle ammunition and Fragmentation Grenades.''

Sergeant Johnson (COM): "Chief, Pelicans are at the river. We've got company, so hustle up!"

Thel 'Vadam: "Grenades! Blow them to bits!"

''Beyond the steep slope is a river substation next to a raging river. A pair of Pelican dropships hover above the river as gunners in their troop bays fire upon a cluster of Covenant troops that have tunneled themselves in the substation. The Pelicans are the extraction force to evacuate the Master Chief and his team.''

Female Pilot (COM): "Hold on. Got a contact."

As the Master Chief and his allies take out the Covenant forces that are closer to the Pelicans, two Banshees streak in along the river.

Female Pilot (COM): "Banshees! Fast and low!"

Echo 51 Pilot (COM): "Break off— NOW!"

''The Banshees launch a high-speed strafing run against the Pelicans, and explosions cascade over them as the Pelicans rock. Echo 051's wingman collides with Echo 51.''

Echo 51 Pilot (COM): "Watch yourself!"

Female Pilot (COM): "I'm hit! I'm hit! ARGH!"

Echo 51 Pilot (COM): "Lost a thruster. Hang on!"

Sergeant Johnson (COM): "Get a hold of her!

Echo 51 (COM): "Negative! We're going down!"

''Both Pelicans streak away around the river bend. Echo 51, in a futile attempt to gain altitude, skims the top of a cliff and crashes out of sight. The 'Wingman' attempts to do the same, but, having suffered more damage than Echo 51, immediately plunges into the river beyond the dam, most likely drowning all of the Pelican's occupants. While Master Chief, Thel 'Vadam, and the Marines fight through to secure the substation despite two waves of Brute-led Covenant Loyalist reinforcements, Johnson and his team exit the wreck of Echo 51 but are beset by a Brute ambush .''

Thel 'Vadam (Single Player} or Marine (Co-op): "The Banshees will return. Back into the jungle, hurry!"

Sergeant Johnson (COM): "Chief, can you hear me?...(static) My bird's down. Half a klick -(static)- downstream from your position."

{If on Easy or Normal}

Marine: "Jackals. On the ridge. Stay low. Looks like they got Carbines."

''After the Chief and 'Vadam pass through the short Jackal-laden "Sniper Alley", they see a bridge. Three Marines are crossing it, under heavy fire, retreating from the wreckage of Echo 51. They hear Avery's voice over the COM unit as a Brute leads a charge against the fleeing Marines.''

Sergeant Johnson (COM): "Come on, you dumb apes! You want breakfast? You gotta catch it!"

Johnson and some of the Marines frag the Brute and his fellow soldiers on the bridge, and run off into a cave.

''The Chief and 'Vadam encounter many hostiles, including a Brute Chieftain on the side of a Phantom, who flies off when either his gunner or much of his troops are eliminated. The Chief and 'Vadam secure the area, and discover Echo 51's crash site by the riverside. The Pelican had flipped over after hitting the cliff, scattering ammunition and weapon racks, including a SRS99D-S2 AM Sniper Rifle and other munitions, around the crash site. The crashed dropship, lying on an outcropping along the valley wall, is surrounded by Assault Rifles, Battle Rifles, and Frag Grenades, and the Pelican's radio is still operational.''

If the Chief or 'Vadam waits by Echo 51's radio.

Crow's Nest Controller: (Echo 51's Radio): "Echo Five-One, this is Crow's Nest. Echo Five-One, please respond! (Pause) Hocus, Five-One is down, divert for emergency evac. Over."

If any of Echo 51's Marines are still alive

Thel 'Vadam: "Again, the Brutes show their weakness."

If any Marines accompany the Chief and 'Vadam.

Marine: "Sergeant Major went this way, Chief. Through the cave."

The Master Chief leads 'Vadam (and any accompanying Marines) through the caves towards where Johnson is being held.

Quid Pro Quo
Rescue at the dam.

{Cutscene}

''At the end the Master Chief and 'Vadam reach a low cliff, viewing a Loyalist-held dam. 'Vadam spots the Chieftain beating Johnson soundly on the far left in front of a small building.''

Thel 'Vadam: "See how they bait their trap?"

''The Chieftain roars at Johnson. Johnson punches the Chieftain in the stomach with no effect.''

Thel 'Vadam: "I will help you spring it."

The Chieftain growls loudly and kicks him back inside the "prison".

{Gameplay}

''The Chief and 'Vadam battle their way across the dam, taking down the Chieftain. They finally reach Johnson, who's been tied up and imprisoned behind a plasma shield.''

Sergeant Johnson: "This isn't as fun as it looks. Cut the power!"

If no Marines came with the Chief or 'Vadam already died, the other three Marines in the prison will still be alive and awaiting rescue.

Marine Escapee: "Brutes were gonna gut us, sir."

The Master Chief releases the plasma shield that was imprisoning Johnson and his fellow Marines.

Sergeant Johnson: "We're even, as long as we're only counting today. Kilo 023, what's your ETA?"

Hocus (COM): "Imminent, Sergeant. Find some cover. Gotta clear a path."

Sergeant Johnson and the Marines grab Covenant weaponry from nearby crates.

Sergeant Johnson: "Roger that, Hocus. Friendly gunship, coming in hot!"

''Two Phantoms arrive, carrying reinforcements. The Chief, 'Vadam, Johnson and any accompanying Marines hold position in the building for shelter until Kilo 23 arrives.''

Sergeant Johnson: "Hocus! Phantom!"

Hocus (COM): "I see 'em! Standby. Going loud. Everyone down!"

''The Pelican Drop Ship Kilo 23 rounds the river bend, directly in front of the two hovering Phantoms. Hocus, Kilo 23's pilot, lets loose a missile barrage, etching the air with vapor contrails as the first Phantom explodes in a brilliant coruscation of light.''

Hocus (COM): "Scratch one Phantom!"

''If any ground forces remain, Kilo 23 will take them out. Kilo 23 fires two missile barrages at the second Phantom, and sends it plunging into the river.''

Hocus (COM): "Scratch two!"

''Hocus lowers the Pelican to the dam for pickup. Johnson, the Master Chief, 'Vadam and any remaining Marines board Kilo 23.''

Sergeant Johnson: {If the Chief reaches the Pelican and stalls} "C'mon Chief, Commander Keyes is waiting!"

Sergeant Johnson: {If the Chief doesn't board the Pelican} "Come on Chief! The world won't save itself!"

If the Chief still doesn't board.

Sergeant Johnson: "Do you or do you not want to finish the fight?"

{Cutscene}

''Kilo 23 takes off. Johnson gives the Chief a pat on the shoulder appreciatively and goes into the cockpit. The back hatch closes and Kilo 23 flies over the first dam, en route to Crow's Nest. The view cuts to an area in the jungle. Sentries on watch in the jungle spot Kilo 23 on approach.''

Marine Sentry: "IFF confirmed. Contact is Pelican Dropship Kilo 23. Over."

Crow's Nest Controller (COM): "Roger that. What's the word, Kilo 23?"

Hocus (COM): "Sierra 117 on board. Request priority clearance. Over."

The two Marine Sentries bump their fists (props) and smile.

Crow's Nest Controller (COM): "Deck's yours. Come on down."

Kilo 23 proceeds to descend into a hole in the ground.

Detours

 * During the chapter entitled Quid Pro Quo, if one wants to bypass the Brute Chieftain, it is possible to take a shortcut. After the cutscene, pick off all the Grunts and Jackals. Then, head towards the dam. There are stairs leading down and up. Go down. You will find yourself in a room. Wipe out any Covenant Loyalists in the room. On the left side of the room, there is a small doorway. If you go in, you will find yourself underneath the main walkway with the Chieftain and other Covenant Loyalists. Walk forward, and you will find yourself past the Chieftain. If the Brute Chieftain goes berserk, however, he may pursue you relentlessly, so be careful. If you also spent some time on the ridge sniping enemies from a safe distance, he will run over the bridge and wait for you, or run under it via the tunnel.
 * When you reach the dam where you must free Johnson, go into the first complex. If you head up the ladder, there is a good sniping spot that gives you a good aim at the enemies, but poor defense. It is also possible to jump from one crate onto a roof, where a Jackal with a Carbine can be found; by jumping through and breaking windows, you can enter that same room.

Glitches

 * In Theater, it is possible to see a six-winged bird. At the start, when you see the first Brute, three birds will sometimes fly low through the area and get stuck on the rock that the Brute is standing on, overlapping and forming a six-winged bird. It will disappear in a few seconds, so you may have to view the level in the Theater and pause when you see it to get a good look at it.
 * There are two vacations that can be performed in this article. (See: Sierra 117 Vacation.)
 * It is possible to "break" the level by tossing a Plasma Grenade at Kilo 23's cockpit at the end of the level. The grenade will pass through the door to the cockpit and kill Hocus, causing the Pelican to fall through the level's geometry and disappear. Caution: Kilo 23 is rather large. if it falls on you, you may be splattered.
 * If, during the Charlie Foxtrot chapter, you shoot Johnson off of the bridge as he crosses it, he will begin to fight the Grunts, and if you are playing on a sufficient difficulty (Legendary with a few gold skulls on), he can be knocked back by grenades and Brute Shot blasts. On rare occasions, he will be held back and rejoin your group, and on other occasions, he may get "stuck" against an environmental obstacle, able to move but refusing to do so. When you go to the bottleneck of the forest before the Brute Chieftain locks Johnson in the room, he will vanish. If done correctly, when you look at Johnson being held by the Chieftain, he will be running and wielding his rifle.
 * You can also grenade him off the bridge. He will generally try to run back up the ridge, and back across the bridge. When this happens, he is unaffected by grenades (they launch him into the air, but while in mid-air, he is posed as if he jumped or fell). He will also rarely respond to shots, though he may occasionally grunt in pain or curse if hit by shots from weapons like the Needler.
 * It's possible to board the Phantom carrying the Brute Chieftain before he flies off to regroup. While inside the Phantom, the Brute cannot be killed. So long as you are on board, and mounted on one of the turrets, the Phantom will always get stuck on the cliff face. Should you dismount, you will fall to your death and the Phantom will resume its journey.
 * When playing on Heroic or Legendary, you can use a glitch to get the Energy Sword that Thel 'Vadam wields. Deliberately weaken the Arbiter by destroying his shield. Either make sure you see his Energy Sword on his hips, or when near enemies, he'll take it out. Kill him by either sticking him with a Plasma Grenade or letting the Covenant kill him (though the latter method will make it harder to find 'Vadam's corpse and his Energy Sword). When the deed is done, pick up the sword and it'll have around one to five energy left. If you want a fully-charged Energy Sword, repeat the steps again, but wait several seconds after 'Vadam respawns, or he will see you as a traitor, and kill you with one shot or melee attack.
 * On Legendary, with all the skulls on, it is possible to climb to the top of the hill where Sergeant Johnson and the Marines climb, but it is a small gap and very difficult to get there. It is on the left of the water. Up there, the marines will run into a small alcove and disappear.
 * In the area where the two Pelicans are shot down by Banshees, as you head back into the jungle, you may be able to grenade the Arbiter off the cliff and onto the waterfall. He will slide down into the water, some distance beneath the surface, and run around for a little while. If you fire at him, you may be able to hear him faintly utter the usual phrases (e.x. "Save your fire for the Brutes!"). He will typically head off to the right (your right, when facing the entrance to the jungle) and travel some distance before reappearing back on the cliff, blindly running into a wall until you approach him.
 * At the end of the level, it is possible to jump inside the Pelican without pressing RB. If you manage to do this, and melee the Marine manning the Machine Gun Turret to death, you can man the turret, but doing so will cause the level to end. You can also melee attack some of the Marines in the seats; they will fall through the floor of the Pelican.
 * It is possible to walk on the riverbed where the Pelicans are shot down. You can use this to take your enemies by surprise, but note that the enemies' bullets will still go through the water.
 * After the Pelicans crash into the river, you can jump down and find their Machine Gun Turrets.
 * At the end of the level, when Hocus's Pelican arrives and the Phantom's wreckage is still in the water, use a Plasma Grenade to blow one of the weapon crates into the water. If you jump onto the crate, it is possible to jump onto the biggest piece of the phantom. You can ride this until it sinks, where you can stay underwater on top of it indefinitely. You can also grenade jump off of the wreckage to get on top of the Pelican.
 * At the end of the level, you can shake Hocus's Pelican. To do this, you'll need the Gravity Hammer and possibly some Plasma Grenades. Jump on top of the Pelican once it comes to pick you up, by using the ledge to the left of it. Whack the tail end with the Gravity Hammer, or throw Plasma Grenades at it, making sure it moves away from the bridge. If done properly, the Pelican should move around.

Mistakes

 * In the August 2007 EGM Halo 3 Story, Sierra 117 was mistakenly said to be the fifth level in the Halo 3 Campaign.
 * The compass on the Assault Rifle is inaccurate - it is out by roughly 90 degrees. Using the compass alone, one would estimate their position as being on top of Shira peak which is of course to the West of Kibo peak. If you scan the horizon, then you would see Shira peak to the left of Kibo peak.
 * Even though the time line takes place in the morning, the actual in-game background scenery tells a different story. If you use the position of the sun, the orientation of Mount Kilimanjaro and the Chief's position at Blind Skull, the time would be late in the afternoon, near the winter solstice. So obviously, the sun is in the wrong place.
 * At the end there is a Marine manning a Machine Gun Turret in the Pelican, but in the cutscene, he is gone.

Easter Eggs

 * When you are approaching the part when you see Johnson and his men running over the bridge, try climbing the rocks in the area behind. You can pick up a Beam Rifle, and if you look closely enough, you might just see a family of Cavemen.
 * Two examples of the trees that have carvings in them are a carved heart that has the initials MF inside the heart and another carved heart that has M + L 7-16-95 inside.
 * The Iron Skull is found on this level.
 * The Blind Skull is found on this level.
 * There are two secret towers outside the map: one behind some two dimensional trees, and one in the same area out by a lighting storm out in the open. They also are behind the invisible wall so you cannot reach them. You can find them if you get outside of the map in the dam area.
 * At the beginning of the level after the Arrival, it is rumored that B-113-421's roars can be heard before entering the pool area. However, this is questionable since B-113-421 is only present and mentioned in Believe which was non-canon.
 * Near the end of the level, you can use the Elevator Glitch where the skull is located to get on top of the glass structure. If you walk across the structure and proceed onto the side of the cliff you will be able to find a lone caveman, which is similar to the cavemen you can find at the beginning of the level.
 * You can also use the Elevator Glitch to get onto the platform above the Skull. You will need the Chieftain's Gravity Hammer to get up. Once you are up, get your co-op pal to commit suicide. They should respawn above the player on the ledge above the skull. Once the map has been overloaded, you can wander around above the dam and up into the hills on foot. There are numerous features like smalls hills and large holes in the ground. It has yet to be fully explored.
 * At the end of the level, on the far side of the dam, if you walk down the pipe running parallel to the water and into a small alcove and look up, it appears that there is an image on the ceiling, but it's yet to be identified.
 * If player one takes too long to board Hocus's Pelican at the end of the level, Johnson might say, "Come on, Chief! The fight isn't gonna' finish itself!" This is an obvious reference to the Halo 3 motto, "Finish the fight!".

Achievement Tips

 * This level is good for getting the "Used Car Salesman" achievement. After rescuing Johnson at the dam, there should be a Phantom outside. Just stick the Phantom's Front-Mounted Turret to get the achievement.

Trivia

 * It is possible to kill the Brute Chieftain on the Phantom by Echo 051's wreckage. However, a Chieftain is still present to push Johnson into the prison, so they may be two different Chieftains, or the one on the Phantom was not scripted to die.
 * For the first time in the entire Halo series, the player doesn't begin playing the game in space but on Earth.
 * This is the only Halo 3 mission where Thel 'Vadam will accompany you through the entire level. (This does not include Halo, because on single player he will be absent during the fight against 343 Guilty Spark.)
 * At the start of the level, players can hear animalistic howls. Instead of native Earth animals, there are actually nearby Brutes.
 * Although the Arbiter skillfully wields an Energy Sword in single-player mode, in co-op, the player controlling him is instead given a Covenant Carbine and a Plasma Rifle.
 * "Bravo Kilo" is another word for "Brute", being phonetic code for "Baby Kong", a joke about the species' ape-like appearance.
 * If N’tho ‘Sraom reaches the middle point cutscene/checkpoint of the level, he will appear in the cutscene instead of 'Vadam (Arbiter) and say his dialogue.
 * This is the only first mission in the entire Halo trilogy (Halo: CE, Halo 2, Halo 3) in which Jackals appear.
 * If you leave any enemies alive after you free Johnson, Hocus will shoot them with powerful missiles, and you can be killed by the blast.
 * Out of all the Halo 3 levels, this one probably goes through the most changes in gameplay on Heroic and Legendary. The most noticeable are the Jackals with Beam Rifles that appear around halfway through the level, and Jackals with Carbines over watching the sleeping Grunts.
 * Sierra 117, along with Crow's Nest, Floodgate, and Cortana, has no drivable vehicles.
 * If you begin killing the surviving marines after all enemies are defeated, and manage to eliminate all of them (except the invincible Johnson), Kilo 23 will fire at you unless you are behind it. Even beside it, it can still fire at you.
 * Over time, Kilo 23 seems to rise higher and higher, until marines entering it seem to jump incredibly high.
 * If you make the marines turn against you, you cannot enter Kilo 23 to end the level.
 * After all the enemies are killed, you can head back to place where the 'Quid Pro Quo' cutscene plays. However, the tunnel entrance would have mysteriously disappeared.
 * If paused in Theater mode right at the start of the level before the game goes to full screen, the Arbiter has no eyes, you can see right through his head.

Achievements

 * Landfall - "Landfall" is an achievement awarded to the player for completing the level on the Normal, Heroic, or Legendary difficulty. It is worth 20 Gamerscore.
 * Iron - "Iron" is an achievement awarded to the player for finding the Iron Skull. It is worth 10 Gamerscore.
 * Guerilla - "Guerilla" is an achievement awarded to the player for earning 15,000 points or more in meta-game free-for-all scoring. It is worth 10 Gamerscore.