UNDERTOW

In a drowned rust-belt America, compete with other salvagers to dive the submerged ruins of flooded cities — where murky water is equal parts cover, oxygen clock, and coffin.

Extraction Shooter PC (Windows) KBM + Controller Early Access · $34.99 Concept · 2026-07-20

Three strata — above water, at the line, below it

The World

2047. The Great Inundation permanently submerged 40% of Memphis's south and west sides. The government withdrew. Corporations, community networks, and black-market brokers all send people in to salvage what's left — data drives, industrial tech, medical supplies, pre-Flood artifacts — from the drowned ruins of the American rust belt. You are one of those people.

Vertical play — map in cross-section

Map Strata

+5M

Topside — Rooftops & Bridge Spans

Open air. Normal audio. Ranged combat. Your dive frame limits mobility slightly. Best sight lines. Highest exposure.

The Waterline — Wading & Surface Swimming

Transition zone. Audio cuts in and out. Chest-deep water slows movement. Most dangerous — visible from both above and below.

−18M

The Bottoms — Submerged Interiors

Muffled world. Sonar replaces footsteps. Silt trails expose movement. Oxygen ticks down. The best loot is deepest.

Core Loop

30-Second Play

Check your O2 gauge. Scan sonar — one ping, 40 meters northeast. Drop below the waterline. Sound cuts to a deep hush. Spot the data locker. A drone sweeps its spotlight. Go still — moving stirs silt. Drone passes. Crack the locker. Push back up.

Core Loop

30-Minute Run

Enter via surface boat. Choose depth tier. Work three buildings. O2 forces a surface trip — or you find an air pocket in an overturned tank car. Enemy salvager surfaces nearby. Standoff. They go left, you go deep. Extract the contract package. Reach your boat. Keep what you pulled. The run ends.

Key systems

Interlocking Systems

🫁

Oxygen Budget

4 minutes at rest. Exertion burns faster. Found rebreathers and sealed air pockets refill it. No O2 = 30-second drowning timer. You set your own run clock by deciding how deep to go.

🔊

Acoustic Duality

Topside: normal extraction audio — footsteps, ricochets, weapon cracks. Underwater: muffled pressure thuds, silt trails, sonar pings. Two completely different audio languages in one map.

📡

Sonar System

Handheld device pings metal masses and life-signs through murk. Useful — but your ping is audible to anyone holding a receiver. Using it is a bet.

🌊

Silt & Visibility

Moving fast kicks up silt — visible trails, reduced sight lines. Hovering still clears the water. Tactical stillness is a skill. Approach by drifting, not thrashing.

🚰

Environment Control

Flood valves and bilge pumps can drain sections (exposing loot) or flood topside routes. High-noise actions — every player in the zone hears the pumps start.

🤝

Faction Contracts

Three contractors: Levine Corp (gear), Bottoms Collective (community standing + unique weapons), Morel's Brokerage (cash). Rep tracks unlock hideout upgrades and map access.

Key features — copyable for your pitch deck

Key Features

Aquatic Verticality
Three distinct play strata — below the waterline, at the surface, and above water on rooftops — each with different movement, audio, combat, and loot economics. No extraction shooter in the genre operates across a water/air boundary as a core mechanic.
Acoustic Duality
Mastering two audio environments is itself a progression curve. Topside: conventional extraction audio with footsteps and weapon cracks. Underwater: muffled pressure thuds, silt trails, and sonar pings. Veterans move between them seamlessly. Novices drown.
Oxygen as Natural Run Timer
Unlike zone-shrink circles, the O2 budget scales with your ambition. A shallow run has minutes of margin. A deep vault dive has seconds. You set your own pressure by deciding how far down to go.
Post-Flood Americana Setting
Drowned rust-belt cities — submerged factories, murky Mississippi water, still-blinking emergency lighting. Rust-orange, algae-green, and concrete-gray. Distinct from military gray, fantasy dungeons, or sci-fi chrome. A real near-future disaster, not a genre set piece.
Battlefield Manipulation via Infrastructure
Activating flood valves and bilge pumps reshapes the playfield mid-run — draining sections to expose loot or flooding topside sniper routes. High-noise actions that telegraph your position. Every decision is a trade.
PvE Mode — No Empty Lobbies
AI salvager population scales dynamically to fill maps. A full PvE-only mode is available from day one, letting new players learn the systems before entering PvPvE. Matchmaking never feels hollow.

Risk register

Honest Risks & Mitigations

Risk	Type	Mitigation
Matchmaking population	Market	Dynamic AI fill + full PvE mode from day one
Underwater movement feel	Design	Week 1 is movement only — no other systems until swimming is right
Complexity cliff	Scope	Guided solo dive tutorial; progressive system unlock (sonar at rep tier 1)
ARC Raiders / Marathon entrenchment	Market	$35 buy-in; genuinely different mechanical hook — not a reskin
Network / underwater physics sync	Technical	Authoritative servers; client-side-only silt visuals; server-authoritative sonar pings

6-week prototype path

Prototype Plan

Week 1 Core movement: walk, wade, swim, dive. Oxygen depletion + surfacing. External playtest. Nothing else until swimming feels right.

Week 2 Graybox map (The Stacks), two depth tiers, basic loot + inventory UI, O2 pickup items.

Week 3 AI scavenger threats, above-water combat, extraction boat mechanic.

Week 4 Underwater combat (altered ballistics, pressure-wave grenades), sonar system, silt-trail visuals, acoustic duality pass.

Week 5 8-player multiplayer test on dedicated server; full run loop; faction contract hooks; flood valve interaction.

Week 6 Vertical slice: 12-player playtest on The Stacks. Tune O2 timings, loot density, AI encounter frequency. Stakeholder presentation build.