Editing Floodgate/Walkthrough

{{Walkthrough infobox

||era=[[Halo 3]]

'''[[Floodgate]]''' is essentially a reversal of [[The Storm]]. Players will have to backtrack from the [[Covenant Empire|Covenant]] [[Covenant Skar'wa-pattern Mantis|Anti-Aircraft Battery]] to Lakebed A, fighting their way through a massive [[The Flood|Flood]] infection. The level is the first Flood-only level in the game, introducing [[Flood combat form|Combat Forms]], [[Pod infector]]s, and [[Flood pure form|Pure Forms]].  

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 [[Halo 3 skulls|skulls]] on [[Legendary]] are [[Halo 3 skulls#Tough Luck|Tough Luck]] and [[Halo 3 skulls#Catch|Catch]]. Tough Luck may cost you a few multi-kill bonuses, but [[grenade]]s 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 [[Halo 3 skulls#Famine|Famine]] are okay on this mission, so try activating one of them too. You may not want to activate [[Halo 3 skulls#Fog|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 [[Halo 3 skulls#Iron|Iron]] activated. [[Halo 3 skulls#Mythic|Mythic]] is a consequence-free multiplier, as there are no Covenant enemies present on this level. [[Halo 3 skulls#Tilt|Tilt]] is not recommended on this or any [[cortana (level)|other]] Flood level.

|Pod infector, Flood Combat Form, Flood Carrier Form, Flood Stalker Form, Flood Ranged Form, Flood Tank Form

|3×

|2.5×

|2×

|1.5×

|colspan=1| {{Pattern|Okarda'phaa|plasma rifle}}

|colspan=1| 2 {{Pattern|Anskum|plasma grenade}}s

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 [[UNSC Marine Corps|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 Pod infectors that reside inside of them. 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 [[Jiralhanae Chieftain|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 [[Halo 3 skulls#Fog|Fog]] skull. Collect Frag Grenades, a [[Gravity hammer (fiction)|Gravity Hammer]], and a [[M90 Close Assault Weapon System|Shotgun]] en route to your first encounter with the Flood.

As you approach the Marines—some of which are gathered behind a pile of sandbags, standing next to weapons lockers—Combat Forms will drop down and start attacking your allies. The safest course of action at this point would be to hang back and wait for the Flood to approach you. Jumping in to save the Marines is a risky decision—seeing as a single Pod infector can make easy work of one, their chances of survival are close to nil, so rushing in an effort to save them will only leave you surrounded by enemies. Make sure you have your Gravity Hammer at the ready, and take full advantage of its splash damage—a single blow can usually wipe out several Combat Forms. The Flood don't carry weapons until later on in the level, so melee weapons are quite useful against them.

Scour the area for more Shotgun ammo—this is your main weapon during this mission, so always be on the look out for more cartridges. There are four Shotguns in the Storage Area, along with Battle Rifle ammo and the Assault Rifles dropped by your fallen allies, so make sure you have a full amount of ammo before moving on. There will also be a Shotgun to the left of the next room.

Inside this warehouse, engaging the Flood over open ground is clearly suicidal. Though only a few carry weapons, their sheer numbers and the scattered Pod infectors (reanimating additional corpses) make it easy to be overwhelmed. The recommended way of dealing with massive amount of Flood is to launch a brief attack before taking a defensive position and encouraging the Flood to come to you.

The next wave of Flood is smaller. If a large group is headed for your position, shoot the [[Fusion coil|Fusion Coils]] as they pass by them; the explosion should engulf a few. Your biggest concern is to avoid being surrounded. 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.

In the next room, you'll find a weapons locker with Battle Rifles in it; it may be a good idea to swap your Shotgun for one of them. After that, as you walk toward the next door, you'll have a [[Character interludes|Cortana Moment]]. Pull out your Gravity Hammer here. If you don't have your hammer then use the trip mine. When you reach the twisting metal corridor, be ready to deal with a large group of armed Combat Forms. If you sprint forward, you can take them all out with two well-aimed strikes. Continue past the [[Suicidal Marine]], exit the warehouse, and you'll arrive at Lakebed B.

A friendly [[Kez'katu-pattern Phantom|Phantom]] will deploy a squad of [[Sangheili|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 [[Betrayal|betrayed]]. To increase their lifespan and your score, skip the [[cutscene]] and [[Sniping|snipe]] the attacking Flood with your Battle Rifle as you approach.

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 for two {{Pattern|Okarda'phaa|plasma rifle}}s to [[dual wielding|dual-wield]]. 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. They usually carry [[Type-25 Grenade Launcher|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 Pod infectors as they approach. Make sure no nearby corpses are reanimated.

To get more points, lower the Elites' shields while fighting the Flood. They'll die, but most times that will draw their Swords and soften up the Flood. These Elites will focus on the Pod infectors, for unknown reasons. Once they die, collect the Swords. Make sure that the sword that you've collected after destroying the Flood has 85% or more energy.

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. This time, take advantage of their aid as you fight the initial wave of Combat Forms and the Pure Forms further ahead. Be warned that they will take little consideration when you run in front of them—it's easy to get caught in the crossfire and get killed by one of their Plasma Grenades.

Finish your objective by heading into the [[Unidentified Flood-captured battlecruiser|Flood ship]] and retrieving what seems to be [[Cortana]]. Remember ''not'' to fire your weapon—if a stray bullet hits a [[Flood blister|Flood Blister]] growing on the wall, it will release several Pod infectors, and since killing them does not earn you any points, there is no benefit in fighting them.

Here, you will see a Marine being ambushed by Pod infectors. Your chance of saving his life is slim, though you will have to kill the Pod infectors 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.

There are no enemies here and no risk of getting lost, so just charge through until you find Cortana. Don't shoot the Flood Blisters unless you want to make the journey harder for yourself. A swarm of Pod infectors can overwhelm you, especially on higher difficulties like Legendary.

[[Category:Halo 3 walkthroughs]]