Descent — Advanced Warfare Zombies Easter Egg Guide

In this guide: full main-quest walkthrough, map layout, recommended loadout, side Easter eggs & songs, boss strategy · Hard, ~40–60 min.

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Advanced Warfare · 2014

Descent

Descent is the fourth and final Exo Zombies map (Reckoning DLC) — a flooded underwater luxury complex and the climax of the Atlas outbreak story. Its very long, very hard main quest Reunion opens the Tidal Generator secret room, uses an Exo Goliath for a flooded-airlock dive, then runs a chain of Oz challenges around two boss fights against the mutated Oz — a number board, a rocket round and a memory simulation — before reuniting the survivors and permanently unlocking the harder Double Feature mode.

Released 29 Sep 2015 Main quest: ReunionBoss: Oz (two fights)Exo Zombies finale
HardEst. time40–60 minPlayers1–4 (solo-capable)Updated8 Sep 2026
Documented here6 walkthrough steps · 5 side Easter eggs (incl. 1 song) · 2 weapon builds · 6 named areas · 4 sources cross-checkedCounted from this page, not estimated. We publish what is documented rather than a percentage of what might exist — nobody can honestly claim to know the full list.

Quick answers

How do you complete the Descent Easter egg?

It is rated Hard and takes about 40–60 min. The run breaks down like this:
  1. Round-based survival for 1-4 players, fully solo-capable; a very-high-difficulty quest (75–120 min) built around a long Oz challenge chain and two boss fights — Oz is the map boss.
  2. Same Exo systems as the other maps (Exo Suit, local power, 3D Printer, Mark upgrade station, EMZ, infection/decon) plus the Exo Goliath heavy suit needed for the flooded airlock route (normal Exo movement can't substitute).
  3. Setup gate: turn all three Tidal Generator valve/bolt mechanisms until their blue lights show to open the secret room, depressurize the Lounge airlock (progress is persistent — chip at it on safe round ends), and take the Goliath (drops ~round 8–9) for the underwater switch.
  4. The first Oz arena has little or no normal point economy, so build one weapon capable of sustained boss damage before round 13 and enter with full ammo and Exo Health.
  5. Several challenges are round-limited or rule-changing (grenade-only, movement-cost, Simon Says, rocket-only), so save a final zombie before triggering the next interaction and carry Contact Grenades before the grenade round rather than buying under pressure.
  6. Completing Reunion permanently unlocks Double Feature — a much harder alternate run (spawn keypad) that ends in a fused/final Oz encounter tied to the secret Double Tap challenge; treat it as a separate prepared run, not an extension of a tired completion.
  7. Useful weapons: KL03-Trident (ricochet, strong in corridors/against drones but risky in co-op Friendly Fire), CEL-3 Cauterizer (drone/boss damage) and the Mk25 MAHEM (the rocket round).
Each stage is written out in full — with the exact locations, the order things must be done in and what to do when a step refuses to trigger — in the walkthrough below.

Who is the boss on Descent?

Oz (two fights). The walkthrough covers the whole encounter: how the fight is structured, where the damage goes, what the arena throws at you between phases, and the loadout worth bringing before you commit to it.

How long does the Descent Easter egg take?

About 40–60 min for a run that already knows the steps, and we rate it Hard. A first attempt takes considerably longer — almost all of the time goes on setup rather than the finale, so knowing the order in advance is what shortens a run.

Can you do the Descent Easter egg solo?

Players: 1–4 (solo-capable). It is solo-capable. Co-op mainly helps with the timed steps, where a second player can hold a zombie or cover a second position, and it makes the ending far more forgiving.

Is there a song Easter egg on Descent?

Yes — “Dies Irae”. Interact with three manta-ray toys (no prompt) — Galleria (by the smashed-glass round aquarium near the Bartoluccini's sign), the Concierge elevator shaft (high on the left wall, boost-jump), and the Tidal Generator exterior (teleporter-pla Full trigger steps for it are in the side Easter eggs section.

What are the main areas on Descent?

6 are documented: Landing / Spawn, Reception / Great Hall, Galleria, Spa / Promenade, Lounge / Airlock and Tidal Generator. Knowing the names matters more than it sounds — most guides, including this one, describe locations by area name rather than by direction.

How many side Easter eggs are on Descent?

5 are documented here — boss, alternate mode, quest suit, song and loadout. Each one has its own steps rather than a one-line mention, so they can be followed mid-game.

When was Descent released?

29 Sep 2015.

Map & Key areas

The map layout first, then the areas worth knowing by name. Map imagery © Activision, self-hosted.

Descent — Layout
Layout

Landing / Spawn

Spawn; the jump-platform challenge over the water and a common Goliath drop point.

Reception / Great Hall

The Simon Says desk console and central routes.

Galleria

The capacitor-charge panel (by the broken aquarium) and a Dies Irae manta-ray toy.

Spa / Promenade

Contact Grenade wall-buy (for the grenade-only round) and a training area.

Lounge / Airlock

The floodable airlock depressurized for the Goliath underwater switch.

Tidal Generator

The three blue-light mechanisms, the secret room (quest console, number board, teleporter, Mk25 station) and the memory-simulation entry.

Steps at a glance

  1. Round-based survival for 1-4 players, fully solo-capable; a very-high-difficulty quest (75–120 min) built around a long Oz challenge chain and two boss fights — Oz is the map boss.
  2. Same Exo systems as the other maps (Exo Suit, local power, 3D Printer, Mark upgrade station, EMZ, infection/decon) plus the Exo Goliath heavy suit needed for the flooded airlock route (normal Exo movement can't substitute).
  3. Setup gate: turn all three Tidal Generator valve/bolt mechanisms until their blue lights show to open the secret room, depressurize the Lounge airlock (progress is persistent — chip at it on safe round ends), and take the Goliath (drops ~round 8–9) for the underwater switch.
  4. The first Oz arena has little or no normal point economy, so build one weapon capable of sustained boss damage before round 13 and enter with full ammo and Exo Health.
  5. Several challenges are round-limited or rule-changing (grenade-only, movement-cost, Simon Says, rocket-only), so save a final zombie before triggering the next interaction and carry Contact Grenades before the grenade round rather than buying under pressure.
  6. Completing Reunion permanently unlocks Double Feature — a much harder alternate run (spawn keypad) that ends in a fused/final Oz encounter tied to the secret Double Tap challenge; treat it as a separate prepared run, not an extension of a tired completion.
  7. Useful weapons: KL03-Trident (ricochet, strong in corridors/against drones but risky in co-op Friendly Fire), CEL-3 Cauterizer (drone/boss damage) and the Mk25 MAHEM (the rocket round).
Prep before each rule-change. Reunion is a chain of challenges, several of which lock the round into special rules — buy Contact Grenades before the grenade-only round, keep support before the rocket round, and gather every player in the Tidal secret room immediately after the rocket round for the final memory (a late player can miss the console/teleporter window). Build a real boss-damage weapon before round 13; the first Oz arena won't fund one for you.

Before you start

What to have in hand before step 1 — from the loadout notes, from the walkthrough itself, and from the map's own quest documentation where the gate is never stated in a step.

Loadout & perks
  • Build one weapon capable of sustained boss damage and enter with full ammo and Exo Health — the first Oz arena has little or no normal point economy. — step 3
  • Avoid ricochet weapons like the KL03-Trident in co-op — the Friendly Fire challenge bans them. — step 5
  • A Host zombie's hit starts the 60-second infection timer to a decontamination unit, and further Host hits shorten it. — from the map's own quest documentation
Items to bring / craft first
  • Take the Exo Goliath (drops around round 8–9) — normal Exo movement cannot substitute for the flooded airlock route to the underwater switch. — step 1
  • Buy Contact Grenades before the grenade-only round rather than trying to buy under pressure once it starts. — step 2
Round and timing gates
  • The first Oz fight is round 13, the mutated form round 20 — have your damage plan ready beforehand. — step 3, step 4
  • Depressurising the Lounge airlock persists between attempts, so chip at it on safe round ends. — step 1
Solo vs co-op
  • Co-op mainly helps the timed steps and makes the ending more forgiving; solo, Friendly Fire instead means evading invulnerable AI survivors while killing the normal enemies. — step 5

Set aside 40–60 min · 1–4 (solo-capable)

Where your run will differ

Gathered here so you meet them before they cost you a run rather than after — quoted word for word from the guide below, or researched from the map's own quest documentation.

Solo or co-op

What changes with your player count. The rest of the guide is the same either way.

  • “The KL03-Trident ricochets (great in corridors and on drones, risky in co-op Friendly Fire)…” Trident / Cauterizer / MAHEM

Full walkthrough

0% complete

The quest in the order this guide runs it — tap any step to jump to it, and it fills in as you tick steps off.

1
Tidal Generator → Lounge

Open the secret room and dive the airlock

+

Shoot the three valve/bolt mechanisms (ground floor under the stairs; wall above the yellow door one flight up; beside the top of the second flight) until each rotates and lights blue, opening the yellow secret room — use the console (interact again even on Access Denied). Depressurize the Lounge airlock (hold interact; progress persists). Take the Exo Goliath (~round 8–9), enter the airlock, follow the red-lit underwater route, melee the floating zombie and hit the switch, then return before the suit is lost.

  • Three mechanisms lit blue — secret room open
  • Lounge airlock depressurized
  • Goliath underwater switch activated
2
Across the complex

Oz challenge chain — phase one

+

Complete each challenge as it comes: Drone (destroy five flying Treasure Drones in a round — each has a limited window before it flies away, so chase them the instant they appear rather than finishing a train first), Capacitor (stand by the Galleria panel and let shock enemies hit you to 100%), Grenade-only round (buy Contact Grenades from Spa beforehand — the round then grants unlimited Contact Grenades, so the real prep is positioning and Exo Health, not grenade stock), Jump (boost across the glowing platforms at Landing to the target circle), Movement-cost round (every move spends points — hold a position), and Simon Says (repeat the Reception desk sequence to eight inputs).

  • Five-drone challenge
  • Galleria capacitor charged
  • Grenade-only round
  • Jump-platform + movement-cost rounds
  • Simon Says (8 inputs)
3
Oz arena

Round 13 — first Oz fight

+

Shoot Oz through the opened glass behind each of four command consoles. Between openings, survive the arena traps — laser ceiling (don't jump), electric floor (stay off it), infected gas (avoid or use the center decon) and turrets (destroy them) — and repeat until his health is gone.

  • Oz damaged through all four console windows
  • First Oz fight cleared
4
Oz arena

Round 20 — defeat mutated Oz

+

Turn on the four corner generators, then lure Oz onto the central decontamination pad and activate it — he's only vulnerable while the pad runs. Repeat the lure → decon → damage cycle (keeping the floor clear for the lure) until his health reaches zero.

  • Four corner generators on
  • Mutated Oz killed via decon-pad windows
5
Arena → Tidal secret room

Friendly Fire and the number board

+

Complete the Friendly Fire challenge (co-op: finish the round without shooting teammates — no ricochet weapons; solo: evade the invulnerable AI survivors and kill the normal enemies). Then, in the secret room, solve the number board by matching each lower digit to the upper row via its action: 1 = Exo Slam a zombie, 2 = jump, 3 = buy grenades, 4 = kill/allow a zombie to die.

  • Friendly Fire challenge completed
  • Number board matched (actions 1–4)
6
Arena → Tidal secret room

Rocket round → the final memory

+

Finish the rocket-only round (the Mk25 MAHEM with unlimited rockets, very slow movement and self-damage — keep distance from targets and walls). Then immediately return to the secret room: every player interacts with the blue console and the teleporter, survives two rounds on the small floating memory map (resembling Outbreak spawn), and returns through the completion sequence — unlocking Reunion and Double Feature.

  • Rocket-only MAHEM round completed
  • All players used the console + teleporter
  • Two memory-map rounds survived — Reunion complete

Side Easter Eggs & extras

Everything beyond the main quest. Tap any entry to open the full how-and-where breakdown.

Boss

Oz

+

The map's boss, fought twice: at round 13 through four console glass windows amid arena traps, and at round 20 as the mutated form, vulnerable only while lured onto the running central decontamination pad.

Alternate mode

Double Feature

+

Permanently unlocked by finishing Reunion: a much harder run activated from the spawn keypad, ending in a fused/final Oz encounter tied to the secret Double Tap challenge. Start it fresh with a prepared team, not off a tired completion.

Quest suit

Exo Goliath

+

A heavy Exo suit (drops ~round 8–9 at Landing or the roof near Exo Health / Tidal Generator) — the only way to survive the flooded airlock route to the underwater switch.

Song

“Dies Irae”

+

Interact with three manta-ray toys (no prompt) — Galleria (by the smashed-glass round aquarium near the Bartoluccini's sign), the Concierge elevator shaft (high on the left wall, boost-jump), and the Tidal Generator exterior (teleporter-platform edge facing the ocean). The third starts the full track.

Loadout

Trident / Cauterizer / MAHEM

+

The KL03-Trident ricochets (great in corridors and on drones, risky in co-op Friendly Fire), the CEL-3 Cauterizer handles drones and boss damage, and the Mk25 MAHEM is issued for the rocket round — the Tidal secret room's experimental station reaches Mk25.

When it isn't working

The stalls that actually cost people runs on this map, and what to do about each.

TroubleshootingEach of these is quoted from the step it belongs to, derived from a gate the guide already states, or researched from the map's own quest documentation — nothing here is guesswork about what might be going wrong.

Doing everything right and nothing happens?

Check the round. Part of this quest is round-gated — it cannot start early however well you play: “Oz challenge chain — phase one Complete each challenge as it comes: Drone (destroy five flying Treasure Drones in a round — each has a limited window before it flies away, so chase them the instant they appear rather than finishing a train first), Capacitor (stand by the Galleria panel and let shock enemies hit you to 100%), Grenade-only round (buy Contact Grenades from Spa beforehand — the round then grants unlimited Contact Grenades, so the real prep is positioning and Exo Health, not grenade stock), Jump (boost across the glowing platforms at Landing to the target circle), Movement-cost round (every move spends points — hold a position), and Simon Says (repeat the Reception desk sequence to eight inputs).” Keep the setup going and come back to it.

Common Descent questions

Direct answers to the specific things players look up mid-game — part locations, puzzle steps and more.

How do I open the secret room on Descent?

Shoot the three valve mechanisms at the Tidal Generator until each rotates and lights blue: one on the ground floor under the stairs, one on the wall above the yellow door a flight up, and one beside the top of the second flight. Then use the console in the yellow room — and interact again even if it says Access Denied.

What is the Exo Goliath and where does it drop?

A heavy Exo suit, and the only way to survive the flooded airlock route to the underwater switch — ordinary Exo movement cannot substitute for it. It drops around round 8 or 9, at Landing or on the roof near Exo Health and the Tidal Generator.

How do I do the airlock dive?

Depressurize the Lounge airlock first by holding interact. That progress persists, so you can chip at it at safe round ends rather than trying to do it in one stretch. Then take the Goliath in, follow the red-lit underwater route, melee the floating zombie, hit the switch and get back before you lose the suit.

What do I need to buy before the grenade round?

Contact Grenades from the Spa. The round itself hands you unlimited Contact Grenades, so the real preparation is positioning and Exo Health — but you have to own them beforehand rather than shopping under pressure.

How do I beat Oz at round 13?

Shoot him through the opened glass behind each of the four command consoles, and survive the arena between openings: do not jump into the laser ceiling, stay off the electric floor, avoid the infected gas or clear it at the centre decontamination unit, and destroy the turrets. Build a real damage weapon before round 13 — the arena has almost no point economy to fund one.

How do I beat mutated Oz at round 20?

Turn on the four corner generators, then lure him onto the central decontamination pad and activate it. He is only vulnerable while that pad is running, so keep the floor clear for the lure and repeat the cycle until his health is gone.

How does the number board work?

Match each lower digit to the upper row by performing its action: 1 is Exo Slam a zombie, 2 is jump, 3 is buy grenades, and 4 is kill a zombie or let one die.

What is Double Feature?

A much harder alternate run, permanently unlocked by finishing Reunion and started from the spawn keypad. It ends in a fused final Oz encounter tied to the secret Double Tap challenge. Treat it as its own prepared run rather than something you tack onto a tired completion.

Why did one of us miss the final memory?

Because the window is short. After the rocket round, every player has to be in the Tidal secret room to interact with the blue console and then the teleporter — someone arriving late can miss it entirely. Gather the whole team before you finish the rocket round.

Visual guides & sources

Screenshots and exact part locations live in these — open one on a second screen.

TrueAchievements — Reunion
Full Reunion route, Oz challenge chain, both fights
Call of Duty — Descent pro tips
Official systems and route overview
SegmentNext — Descent Reunion guide
Independent step sequence and challenge cross-check
Call of Duty Wiki — Double Feature
Post-Reunion mode and Double Tap cross-check

Map discussion

A shared community board for Descent — posts are public, saved on the server and visible to everyone across devices. Handy for strategies, spawn variations you've noticed, or steps to double-check. Please keep it civil and on-topic.

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Part of the Zombies Easter Egg Codex — step-by-step Call of Duty Zombies Easter egg guides for every map. Open Descent in the interactive codex for the solvers and map discussion.