Operation: Floodgate – Full Mythic+ Walkthrough

Operation: Floodgate – Mythic+ Dungeon Guide (Season 2, The War Within)

Introduction

Operation: Floodgate is a Season 2 dungeon in The War Within, featuring a mix of industrial chaos and swampy hazards. This guide focuses on Mythic and Mythic+ difficulty and provides a detailed breakdown of trash mobs, boss mechanics, and routing tips for effective group coordination. Whether you're timing a high key or just learning the ropes, this guide will help your party navigate the complex mechanics and avoid the most dangerous pitfalls.

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Dungeon Overview

Key Mechanics

• Weapon Stockpiles: Five must be collected throughout the Waterworks to unlock the third boss. These are in fixed locations—make sure at least one player interacts with each pile as you pass.

• Goblin Glider Shortcut: A glider near a dam-side weapon stockpile allows for fast travel across the map. Coordinate with your group before jumping—let the tank lead to avoid accidental aggro.

• Zeppelin Hazard: A patrolling Zeppelin targets players with missile indicators in the swamp zone. After defeating the second boss, a rocket becomes available to shoot it down, clearing a safe path forward.

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Waterworks Trash Breakdown

Shreddinator 3000 (CC Immune)

• Shreddation: Spawns sawblades under each player — spread and dodge.

• Flamethrower: Frontal cone that rotates. Tanks must face it away; group should track rotation to avoid damage.

Mechadrone Sniper

• Trickshot: Interrupt this channeled shot to reduce pressure on the group.

• Snipe: Targets random players; consider defensives if multiple hit the same person.

Loaderbot

• Wind Up: Fixates a random player; kite it and use stuns or knockbacks to break the channel.

Venture Co. Surveyor

• Surveying Beam: Channel that targets one player; leaves damaging puddles. Interrupt or use CC.

• EZ-Thro Dynamite III: Additional fire-based splash damage to random players — avoid stacking.

Darkfuse Soldier

• Blood-Infused Strikes: Stacking DoT on the tank; dispel or rotate defensives.

Darkfuse Hyena

• Pack Tactics: Buffs nearby hyenas — avoid multi-pulls.

• Bloodthirsty Cackle: Interrupt or use soothe to remove enrage effects.

Venture Co. Architect (CC Immune)

• High Ground: Grants immunity while positioned on scaffolding — destroy scaffolding to bring them down.

• Nailgun: Applies a bleed and root — dangerous if overlapping with other AoEs.

Venture Co. Diver

• Plant Seaforium Charge: Drops bombs — avoid the planted explosives.

• Harpoon: Interrupt to prevent forced pulls and random damage.

Bombshell Crab

• Pinch: Tank ability with stacking slow.

• Crabsplosion: On-death AoE — stagger kills to avoid group wipes.

Darkfuse Demolitionist

• R.P.G.G.: High-damage explosion — avoid or interrupt reload via CC.

Darkfuse Bloodwarper (CC Immune)

• Blood Bolt: Interrupt to reduce tank pressure.

• Warp Blood: Applies a healing absorb and causes group-wide damage — prepare cooldowns and healing.

Darkfuse Inspector

• Surprise Inspection: Random teleport + frontal — use CC to prevent it.

Disturbed Kelp

• Jettison Kelp: Group-wide damage channel — interrupt or prepare healing.

• Restorative Algae: Interrupt or purge to prevent mob healing.

Unpulled Swamp Mobs

Usually skipped in optimal routes, but useful to know if pulled accidentally:

• Waterworks Crocolisk: Applies Vicious Chomp to tanks — kite to drop stacks.

• Undercrawler: Casts Lethargic Venom — interrupt or dispel poison.

Boss Encounters

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Boss 1: Big M.O.M.M.A.

This fight alternates between two phases:

• Add Phase (Mechadrones)

• Burn Phase (boss takes massive damage)

Add Phase Mechanics

• Mechadrone: Maximum Distortion – Interrupt to prevent group damage.

• Doom Storm – Swirls spawn on random players; dodge quickly.

• Shoot – Random target physical damage; watch group health.

Big M.O.M.M.A. Abilities

• Sonic Boom: Targets a random player with a delayed wave that:

  • Silences on hit

  • Pushes back

  • Explodes in a 7-yard radius at the end

  Counter: Targeted player should run away from the group and dodge the wave. Use movement speed abilities if needed.

• Electrocrush: Tank hit + 10s nature DoT

  Use defensives proactively.

• Kill-o-Block Barrier: Casts at 100 energy — reduces boss damage taken by 80% and pulses AoE every 2.5s

  Prevent it by killing all 4 Mechadrones before energy reaches 100.

Burn Phase

• Jumpstart: Once all adds die, boss takes 200% increased damage for 12s, but the group takes heavy AoE every 1.5s

  Burn boss, use healing/damage cooldowns, and reposition carefully — electricity puddles will shrink your space.

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Boss 2: Demolition Duo (Bront & Keeza)

Bront and Keeza do not share health. Keep damage balanced to avoid the Divided Duo stacking buff.

Bront Mechanics

• Wallop: Tank-targeted slam + 5yd AoE

  Tanks should use defensives and stay clear of melee players.

• Barreling Charge:

  • Charges 2 random players, then the tank.

  • Stuns anyone hit.

  • Destroys bombs if it passes through them.

  Players must bait charge through bombs, then move out of its path.

Keeza Mechanics

• Kinetic Explosive Gel: Magic DoT applied to a random player

  • Explodes in 5yd radius on dispel

  • Also clears bombs on contact

  Spread out before dispel to avoid splash damage.

• Quick Shot: Random-target damage

  Be cautious if this hits someone with the Gel debuff.

• B.B.B.F.G.: Spawns wide damaging lines to avoid.

Bomb Mechanic

• Big Bada BOOM!: Spawns 6 bombs that explode after 30s, applying a stacking DoT to the group.

  • Clear them using Barreling Charge or Gel explosions.

  • Avoid puddles left behind when bombs are destroyed — they deal damage on contact.

Strategy: Assign players to manage bomb clearing. Balance boss HP, use defensives for overlapping damage.

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Boss 3: Swampface

Central mechanic: Razorchoke Vines

• 4 players (non-tank preferred) are tethered in pairs for 24s.

• If partners move more than 14 yards apart, the vines snap them back together.

Coordinate movement with your partner — especially while dodging other mechanics.

Other Abilities

• Mudslide: Large line AoE at a random player

  Everyone should stay loosely spread and dodge.

• Awaken the Swamp:

  • Spawns 5 circles that explode one after another, sending out waves and doing group-wide damage.

  Dodge the outward waves and prepare for healing throughput.

• Sludge Claws (Tank Mechanic):

  • Deals physical + nature damage and applies a healing absorb.

  Healers should prioritize dispels and tanks should use defensives during overlaps.

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Boss 4: Geezle Gigazap

Energy-based fight with alternating Turbo Charge phases and heavy movement.

Turbo Charge (Every time boss hits 0 energy)

• Boss jumps to the control panel and channels for 10s:

  • Constant AoE ticking damage

  • Shoots damaging lines at random players every 2s

  Healers should use cooldowns here; players dodge the lines.

• After Turbo Charge: Dam Rubble falls, creating Dam Water puddles. These are vital for handling the next mechanic.

Leaping Sparks

• 5 Sparks spawn and fixate each party member, stunning on contact.

• Can only be destroyed by luring them through Dam Water.

• If a Spark touches water:

  • It dies

  • The puddle becomes Shock Water (dangerous and unusable for future sparks)

Each player must find their own water puddle to kite their Spark through. Limited puddles = high coordination check.

Other Abilities

• Gigazap: 4yd AoE on 2 random players + DoT

  Spread out to avoid cleaving others or hitting water puddles.

• Thunder Punch (Tank Mechanic):

  • Physical hit + 4s nature DoT + knockback

  Keep your back to the room’s edge or console to avoid being thrown off or into Shock Water.

Strategy: Position puddles well, clear Sparks individually, and spread out to avoid overlapping AoEs.