Floodgate is essentially a reversal of The Storm. Players will have to backtrack from the Covenant Anti-Aircraft Battery to Lakebed A, fighting their way through a massive Flood infection. The level is the first Flood-only level in the game, introducing Combat Forms, Infection Forms, and Pure Forms.

Overview[edit | edit source]

Finding your way around Floodgate shouldn't be much of a problem—you're backtracking your footsteps all the way to Lakebed A in the previous level. This is the first mission in which you fight the Flood, making it a new experience when fighting the newly evolved Pure Forms. Keep in mind the useful weapons when in combat with them and any other Flood, especially on higher difficulties. This is a good starter mission for engaging the Flood. You can test the best technique of dispatching them without dying, because although there are some instructions about where to go and what to do, there are a billion other techniques that work just as well.

The recommended skulls on Legendary are Tough Luck and Catch. Tough Luck may cost you a few multi-kill bonuses, but grenades aren't a vital part of your arsenal during this mission. Catch is, as in all other Flood-only missions, a consequence-free multiplier—the Flood don't use grenades, so leaving it inactivated is a waste. All other skulls except Famine are okay on this mission, so try activating one of them too. You may not want to activate Fog if you aren't skilled at close combat with the Flood. Due to its short length, this level is arguably the easiest level to beat with Iron activated. Mythic is a consequence-free multiplier, as there are no Covenant enemies present on this level. Tilt is not recommended on this or any other Flood level.

This is one of the Flood levels where you cannot get Plasma Grenades unless some of the Elites die.

Weapon instructions in this level can be freely followed, as you will receive new weapons upon completing the level—specifically, the MA5C Assault Rifle and a Sniper Rifle

Statistics[edit | edit source]

New in Floodgate[edit | edit source]

Introduced in this level...
New Enemies: Flood Infection Form, Flood Combat Form, Flood Carrier Form, Flood Stalker Form, Flood Ranged Form, Flood Tank Form
New Vehicles:
New Items:
New Weapons: Flamethrower, Energy Sword

Campaign Scoring[edit | edit source]

Points information
Exterminator Achievement Milestone: 15,000 points
Recommended Multiplier: 8x (Tough Luck (1.5) + Catch (1.5) + Thunderstorm (3) + Mythic (2))
Time Bonus
0-10 min 3x
10-15 min 2.5x
15-20 min 2x
20-25 min 1.5x

Starting Weapons[edit | edit source]

Player V
Starting Point >
Mission Start Rally Point Alpha Mission Start
Rally Point Alpha
John-117 Primary Weapon
BR55 Heavy Barrel Service Rifle BR55HB SR Battle Rifle N/A N/A
Master Chief Secondary Weapon
MA5C Assault Rifle MA5C Assault Rifle N/A N/A
Master Chief Grenades
2 M9 High-Explosive Dual-Purpose Grenades 2 M9 High-Explosive Dual-Purpose Grenades N/A N/A
Master Chief Primary Weapon
BR55HB SR Battle Rifle BR55HB SR Battle Rifle BR55HB SR Battle Rifle BR55HB SR Battle Rifle
Master Chief Secondary Weapon
MA5C Assault Rifle MA5C Assault Rifle MA5C Assault Rifle MA5C Assault Rifle
Master Chief Grenades
2 M9 High-Explosive Dual-Purpose Grenades 2 M9 High-Explosive Dual-Purpose Grenades 2 M9 High-Explosive Dual-Purpose Grenades 2 M9 High-Explosive Dual-Purpose Grenades
Thel 'Vadam Primary Weapon
N'tho 'Sraom Primary Weapon
Usze 'Taham Primary Weapon
Type-51 Carbine Type-51 Carbine Type-51 Carbine Type-51 Carbine
Thel 'Vadam Secondary Weapon
N'tho 'Sraom Secondary Weapon
Usze 'Taham Secondary Weapon
Type-25 Directed Energy Rifle Type-25 Directed Energy Rifle Type-25 Directed Energy Rifle Type-25 Directed Energy Rifle
Thel 'Vadam Grenades
N'tho 'Sraom Grenades
Usze 'Taham Grenades
2 Type-1 Antipersonnel grenades 2 Type-1 Antipersonnel grenades 2 Type-1 Antipersonnel grenades 2 Type-1 Antipersonnel grenades

Walkthrough (In-depth)[edit | edit source]

It Followed Me Home (Mission Start)[edit | edit source]

Storage Area[edit | edit source]

If you're skilled with the Battle Rifle and are trying to get the Exterminator achievement, you may want to look to the right of the path that is about to be described. There, in the distance, if you are quick enough, you may see several Flood Combat Forms assault a small group of Marines. They will begin to retreat, though if you fire at them, they may turn to face you, and strafe instead of running away. For quick kills without using a lot of ammo, aim for their chests to kill the Flood Infection Forms that reside inside of them. On Heroic you will get 38 points from that, and on Legendary you will get twice the amount on a headshot. When you're done with that, proceed as you normally would...

Backtrack down the path you took to get to the Anti-Aircraft Battery. Make your way down the hill, and enter the Storage Area where you previously fought the Brute Chieftain. There will be a building on your right. Just after the checkpoint—right when a Marine says, "All squads, report!"—a Flood Combat Form will appear on the roof and jump over the street. If you kill this Flood during his jump (or right as he starts to jump), he will drop the Fog skull. Collect Frag Grenades, and swap your Assault Rifle for the Gravity Hammer. Take the grenades from the dead Brutes and Marines in the area, and do not switch with any other weapon unless you're very bad with the Battle Rifle.

As you approach the Marines — one or two of which are near some sandbags and ammo lockers, a massive horde of Flood will attack - a mix of Infection and Combat Forms drop onto the ramp, while another group of Infection Forms drops on the marines near the ammo lockers. The Flood will generally kill the marines they land on, so toss a few grenades to kill them, though doing so too early can cause a betrayal. On Heroic and Legendary, a squad of Combat Forms will appear from the fence, so once the Flood spawn, you may want to hang back and let them funnel to you. Sometime later, all Combat Forms will disintegrate into a harmless Infection Form that simply wanders around, though there may be a few revived Combat Forms you may need to deal with. Collect Battle Rifle ammo before proceeding to the next section.

Warehouse[edit | edit source]

Upon entering the warehouse, two more sets of Marines are ambushed by numerous Combat Forms. It's possible to save the Marines, though don't expect this to occur frequently on higher difficulties. Like the first set of Combat Forms you just encountered, the Combat Forms initially seen do not wield any weapons. Snipe the Combat Forms with your Battle Rifle; if any go up the stairs, swap to your Gravity Hammer and pummel them. As more Combat Forms fall, a second squad of Combat Forms will jump from across the room, all carrying Spikers.

There is some potentially useful equipment here, including a Trip Mine, a Bubble Shield, and a Regenerator; these items are common throughout the mission. The most useful is probably the Regenerator, as armed Combat Forms can rapidly deplete your shields.

The next wave of Flood is smaller. If a large group is headed for your position, shoot the Fusion coils as they pass by them; the explosion should engulf a few. Your biggest concern is to avoid being surrounded. The Flood will also come behind you, so watch your back. There will also be one Carrier Form, but it's too far to hurt you. Otherwise, this battle should be relatively easy. The metal walkway that leads to the next room is home to a Flamethrower. It's enjoyable to use, but relatively slow and limited in range—which can be problematic, as you'll really need to destroy Combat Forms quickly on Legendary. Use it to torch the prone Flood bodies, which is quicker than using melee attacks. Swap your equipment if you haven't yet for the Deployable Cover.

Clear off all the enemies and stock up on grenades if needed. Go through the given path and go down a hole, or break a window for faster access. When landing into this room a Cortana Moment occurs. Stock up on more Battle Rifle ammo and leave the room. A large squad of Combat Forms appear around the bend, so drop the Deployable Cover; if used correctly, they'll either get stuck or funnel one at a time to easily pick them off. The Deployable Cover is extremely useful because all the Combat Forms here are armed with either Spikers, Plasma Rifles or SMGs which can easily shred your shields and then kill you. You'll know when the fight is over when the Suicidal Marine starts talking; restock on Battle Rifle ammo, grab the Regenerator if desired and head out to the lakebed.

Shadow of Intent (Rally Point Alpha)[edit | edit source]

Lakebed B[edit | edit source]

A friendly Phantom will deploy a squad of Elites at your location. They are a big help, but they can be a nuisance if you're actively seeking a high score—valuable kills will be stolen. The Elites also tend to jump into the line of fire when you least expect it, and their furious grenade lobbing could lead to you being unintentionally betrayed.

To increase their lifespan and your score, skip the cutscene and snipe the attacking Flood with your Battle Rifle as you approach. If you do not want the Elites to die too fast, use your battle rifle (if you have it), and start killing the Combat Forms by jumping and so forth. Once they reach the ramp, they will slowly move to your position (their walking speed), allowing for easy headshots and points for your Exterminator achievement if you haven't gotten it. Deal with the Flood quickly, as on the harder difficulties they will die almost instantly and leave you with no allies apart from the Arbiter. Since the Flood attack up close, the Elites will also attack them up close and rarely switch to their Energy Swords. They also have a very poor melee attack that barely does any damage on them, so try to kill as many as you can so they don't do this.

Most of the time, there will always be an Elite Combat Form around, but it's not strong to harm you and your allies a lot. This is only if you stay in the area too long without starting the cutscene. This Combat Form at the moment does not use shields, so snipe it if you want to as these give the most points out of all Combat Forms.

(Occasionally, the Catch skull may cause them to grenade themselves off the cliff and to their deaths.)

The Elite landing party will thin down the force of Combat Forms situated on the side of the lakebed. If you find any intact Flood bodies, destroy them to prevent their reanimation. When the area is visually clear, search the nearby structure for two Plasma Rifles to dual-wield and an Energy Sword. Slightly down from the structure is another dead Marine with a Battle Rifle and two additional frag grenades. Approach the ramp slowly, and immediately pull back into cover as Combat Forms leap from the cliff to your left. Dispatch them at range using your Plasma Rifles/Battle Rifle. They usually carry Brute Shots and Shotguns at this point, so take care not to get hit, and be ready to duck behind cover.

More Combat Forms will advance down the ramp, so knock them over before they open fire. Two Carrier Forms will waddle down the slope; toss some Frag Grenades or Plasma Grenades to rapidly blow them up, and then aim to mop up the swarm of Infection Forms as they approach. Make sure no nearby corpses are reanimated, though the Elites and your default ally will probably have killed all of the Infection Forms.

Factory B[edit | edit source]

As you enter the factory, avoid trying to fight the Combat Forms in the open. The Combat Forms are in a very large swarm, using Spikers and Plasma Rifles (the former is much more common in this swarm). Snipe off as many as you can before proceeding from the low corridor, scanning the intact bodies for some dual-wielding action.

As you leave the low corridor, additional Combat Forms will drop down from the ceiling. They'll generally land in close proximity of each other, so drop your second Plasma Rifle and throw a grenade or two into their midst. Then, retrieve your second Plasma Rifle and dispatch any that remain. Quickly run underneath the walkway to avoid being shot by the second wave. They'll arrive through the door above, so stay alert. Wait at the bottom of the stairway to take out any that run down. The Arbiter will take care of the rest. It could help to deploy a Regenerator at the bottom of staircase.

If daring enough, you can lob grenades at the door to score several kills, or attempt to headshot the Combat forms coming out of the door. The Combat forms that come out from the door will either jump down or go down the stairs and attack there. Your Energy sword is perfect to knock them to bits.

If you used the Regenerator, there is another one beside a dead Marine and a loaded Battle Rifle with two more extra clips.

On the upper level of this building, you can find a second Flamethrower. This isn't the best of weapons to deal with the Combat Forms, but it should make easy work of the Pure Forms outside.

Lakebed A[edit | edit source]

Another group of Elites is usually (but not always) dropped off as you exit the warehouse—they will be deployed if the previous group of Elites has been wiped out. A single Flood Stalker Form is lurking in the pile of crates as you enter the lakebed, its carapace making it very hard to spot in most cases. As soon as it detects the player, it'll jump down and transform into a Flood Tank Form which will likely kill all of your Elites if it survives; plasma weaponry, or the Flamethrower you obtained recently will be enough to dispatch them. Additional Flood reinforcements will appear, with shielded Combat Forms making their appearance here; on Heroic and Legendary, one will appear with an Energy Sword, and you will want to dispatch it from long range before it gets close.

Detach the Machine Gun Turret and walk on the pathway to the side; not the lakebed. Some Flood may attempt to flank you from this side, and you'll be protected from the Combat Forms that jump onto the lakebed. Your allies will always walk down onto the lakebed to deal with the Combat Forms. Typically a single Flood Ranged Form will be lurking at the structure in the distance, so grabbing some Plasma Rifles will dispatch it quickly. Numerous Tank Forms will be waiting near the structure, and you'll want to use an Energy Sword, Flamethrower or plasma weapons to deal with them. Most if not all of the Combat Forms will have already been killed, but they shouldn't pose a threat to you anyways.

Once all enemies in this area are cleared, jump down and enter the Indulgence of Conviction. There shouldn't be any enemy resistance at all by this point, but rarely players may need to deal with a whole squad of Combat and Pure Forms who did not move to meet the player and their allies in the previous fight.

Infinite Devil Machine[edit | edit source]

Finish your objective by heading into the Indulgence of Conviction and retrieving Cortana. Remember not to fire your weapon—if a stray bullet hits a Flood Growth Pod growing on the wall, it will release several Infection Forms, and since killing them does not earn you any points, there is no benefit in fighting them. However, you can knock the dead Elites down the hole and shoot the pods for more points if you are trying to get the "Exterminator" achievement. The Combat Forms aren't shielded and won't attack the player unless they get too close to them.

Walkthrough (Brief)[edit | edit source]

It Followed Me Home... (Mission Start)[edit | edit source]

Backtrack along the path you took to get to the Anti-Air Battery. On the left side, when first heading south, there is a Gravity Hammer lying behind an overturned vehicle. Swap your Assault Rifle for it.

As you enter the next section, where Marines are waiting for you, Combat Forms will drop from the roof. Take advantage of the Gravity Hammer's splash damage or your Battle Rifle's headshot capability to make short work of the Flood. After the engagement, you may swap your Hammer for a Shotgun if you so desire. Continue through the office behind the door through which you entered this area on The Storm.

Here, you will see a Marine being ambushed by Infection Forms. Your chance of saving his life is slim, though you will have to kill the Infection Forms regardless. Inside the main room, there is a swarm of Combat Forms. Get their attention by shooting or lobbing frags at them, and then pick them off with a Shotgun or Battle Rifle as they climb (or jump) up the stairs to the office. If you still have your Hammer and are feeling daring, you can exit the office, smash a few Combat Forms, and then retreat back to the office; staying outside, however, will get you surrounded and killed.

When the Flood have been dealt with, grab a Trip Mine, a Regenerator, or a Bubble Shield, and then continue forward. The next section after the wall of shipping containers contains additional Combat Forms; kill them. Go up the stairs, across the bridge, and around. Drop through the hole for a Cortana Moment. Pass the two weapons lockers, and then turn right. There are several Flood camping around the 180° turn; counter this by throwing two grenades, and then finish off any survivors. (Frags can be bounced off of the wall, to hit them without exposing yourself.) Pass the Suicidal Marine and continue.

Shadow of Intent (Rally Point Alpha)[edit | edit source]

Several Elites will be dropped at your location. Aid them in killing the Flood, and then continue. Go through the indoor area. A swarm of Flood will jump down from where a swarm of Drones flew in The Storm. As always, you will be fine if you don't let them surround you.

When you get outside, kill the Stalker Form. If it turns its back and changes form, it can be assassinated. Kill the Combat Forms in this area, then deal with the Pure Forms. Grab the Machine Gun Turret, detach it, and walk down the path to the right, killing anything in your way. When you pass under the metal pipe, be careful because there are several Pure Forms. Kill them and make your way to the entrance to the Flood ship.

Alternatively, if you are skilled at deploying equipment in precise locations, you can place a Deployable Cover in front of the Machine Gun Turret (without detaching it) to create an instant machine-gun nest that is extremely powerful against Pure Forms. Like any machine-gun nest, it is weak against flanking; keep your Elites alive (give supporting machine gun fire) so that they can defend your flanks. If you are playing Co-op, your partners can defend you. One Ranged Form will be out of the machine gun's range, so kill it with your Battle Rifle. Make your way to the entrance to the Flood ship.

Infinite Devil Machine[edit | edit source]

There are no enemies here and no risk of getting lost, so just charge through until you find Cortana. Don't shoot the Flood Growth Pods unless you want to make the journey harder for yourself. A swarm of Infection Forms can overwhelm you, especially on the higher difficulty.

Videos[edit | edit source]

Preceded by
The Storm
Halo 3 Campaign Walkthrough for:
Succeeded by
The Ark

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