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. Also, this is 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 Gamer points. Upon earning 15,000 points in Campaign Scoring, the player will be awarded with the Guerilla achievement and 10 gamer points.

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.

Available Weapons

 * Assault Rifle
 * Pistol
 * Heavy Machine gun (Heroic or Legendary only)
 * Plasma Cannon (only dropped by Phantoms)
 * Plasma Pistol
 * Needler
 * Plasma Rifle
 * Sniper Rifle
 * Spiker
 * Frag Grenade
 * Plasma Grenade
 * Gravity Hammer
 * Battle Rifle
 * Covenant Carbine
 * Brute Shot (Heroic or Legendary Only)
 * Particle Beam Rifle (Heroic or Legendary Only)
 * Energy Sword (Only by killing Thel 'Vadam. It has very little battery left)

Plot
Having been found by Johnson, his Marines and the Arbiter Thel 'Vadam, the Master Chief is escorted through the jungle not knowing there was trouble ahead. Johnson has with him two squads of marines but after spotting a Covenant Phantom overhead, he decides to split them into two teams 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. They also have to face a Jackal Marksman. Around the time they finish mopping up the first group of Covenant, 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 Brute who was torturing the Marine, they are told 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 their cause.

Later on, UNSC forces and Thel 'Vadam make it to the river for evacuation, but the Pelicans at the evacuation point are already under attack by Covenant infantry. Johnson is seen firing from the back of one of the Pelicans with a Machine Gun Turret and with combined fire, the Covenant are momentarily pushed back. However, before the Chief and Vadam can reach them, Banshees show up and fire on the Pelicans with their Fuel Rod Cannons. Heavily damaged, they make a fiery exit out of the Chief's sight and more Brute and Grunt reinforcements show up to mop up survivors. 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 afterwards come across him and his squad fleeing from the crash site, pursued by Brutes and Grunts. The Chieftain mentioned earlier pulls his own Phantom out of the fight to regroup.

They desperately try to catch up with Johnson, killing dozens of Grunts, many Brutes and a handful of Jackal Snipers or marksman jackels (depending on the difficulty) that were crowded around the area. 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 this is the same Chieftain that killed Bravos 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 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 and kills 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''{Whisper}: "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(Whisper): "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, taking them by surprise. They regroup.''

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

''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.''

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

Thel 'Vadam: "The Grunts' new-found courage is but fear. When we are victorious, all who serve the Prophets will be punished."

Reply in Co-op: Female Marine or Male 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 Marine Sergeant on a log {It is possible and optional to save the Marine by killing the Brute}.

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) "Uhh, 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 drop ships, hover above the river, and their door gunners fire on a cluster of Covenant troops that have tunneled themselves in the substation. They 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 clear the site of Covenant that is nearer to the Pelicans in the substation, 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! AAARHHHH!"

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 attempts in vain to gain altitude, instead skimming the top of a cliff and chrashes out of sight. Likewise, the wingman attempts to do the same, but having suffered more damage than Echo 51, immediately plunges into the river beyond the dam, mostlikely drowning all ocupants. 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 leave the wreck of Echo 51 but are beset by a Brute ambush .''

Thel 'Vadam/Marine{Co-op only}: "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 Sniper-laden gorge "Sniper Alley", they see a bridge. Three Marines are crossing it, under heavy fire, retreating from the crashed Pelican Echo 51. They hear a familiar 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 flipped over after hitting the cliff, scattering ammunition and weapon racks in the area, including a SRS99D-S2 AM Sniper Rifle and other munitions. To get to Echo 51, go under the bridge towards the river. At the rivers edge, walk towards the valley wall on your right. The wreckage of Echo 51 is on an outcrop. There are ample frags, assault and BR ammo. Echo 51's radio is still operational, however.''

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.''

''Keep on going. When the passageway ends, turn to your left and you will be on the other side of the dam. You can run and rescue Johnson without killing all those Covenant on the main walkway on the dam.''

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 be still alive and await 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. Kilo 23 shuts the back hatch and 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 spots 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 onboard. 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 land in 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.
 * 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 an otherwise inaccessible room that provides a good view of the entire walkway.

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 four 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.
 * 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.
 * 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 bust 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). After that, pick up the sword and it'll have around 1 to 5 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. Also, if you 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 now-detached Machine Gun Turrets.
 * At the end of the level, when Hocus's Pelican arrives and the phantoms 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.
 * 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 similiar to the cavemen you can find at the beginning of the level.
 * 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 it self!" 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 a few times and you get the achievement.

Miscellaneous

 * 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 campaign 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, as thought, it is 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.
 * Sierra 117 is the only first mission in the entire Halo franchise (Halo: CE, Halo 2, Halo 3, and Halo Wars) in which Jackals appear.
 * If you leave any enemies alive after you free Johnson, Hocus will shoot them with powerful missiles, and if you're too close, you will be killed.
 * Most of the time the machine gun turret off the pelican when you meet up with the Marines at the dam has fallen off the Pelican, sometimes its still on the Pelican.
 * 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 (Level), and Cortana (Level), has no drivable vehicles.

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 Gamerpoints.
 * Iron - "Iron" is an achievement awarded to the player for finding the Iron Skull. It is worth 10 Gamerpoints.
 * 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 Gamerpoints.