SZ
SZ
SZ
SzGames

Loading Sub-Optimal...

This may take a few seconds

Sub-Optimal

3.8 / 5
12,125 plays
adventure

Game Information

Developer: SZ Games
Rating:
3.8/5
Released: April 2024
Last Updated: June 2025
Technology: HTML5 (Unity WebGL)
Platform: Browser
Size: ~15 MB
Plays: 12,125
Mobile Support: No

Tags

adventure (194) mouse (1038) keyboard (1038) easy (376) 2D (0) indie (1038) free (1038) html5 (1020)

About Sub-Optimal

Dive into the wild and whimsical depths of Sub-Optimal – the indie browser sensation that’s sweeping party game fans off their fins! As the 2nd Place Winner of Game Jolt's Party Jam, this adrenaline-fueled 2-4 player online co-op adventure throws you and your friends into a quirky, chaos-filled submarine, where teamwork is the only thing keeping you from a watery grave.

Set sail across four unique oceanic levels, each bursting with vibrant hand-crafted visuals, unpredictable hazards, and monstrous boss battles. Your ragtag crew must coordinate under pressure: pilot the submersible, operate powerful cannons and drills, scan for danger with sonar, shield against incoming threats, and keep the map updated—all in real time. Communication is key, so rally your squad, jump into the dedicated Sub-Optimal Discord for seamless voice chat, and experience true co-op mayhem.

No two dives are the same. The journey from novice explorers to deep-sea legends will have you ducking tentacles, outmaneuvering underwater fiends, and combining gadgets with last-second precision. The true test awaits in the epic confrontation with the Mighty Kraken, a boss fight packed with surprises and requiring full squad synergy.

Sub-Optimal respects your time: the easy-to-learn gameplay makes onboarding a breeze, letting everyone contribute without feeling left behind. Yet there’s plenty of depth for seasoned gamers who crave strategic mastery and wild co-op moments. Best of all, it’s totally free to play in your browser—just grab a friend (or three) and get ready for laughs, shouts, and unforgettable undersea adventures.

Forget solo quests—make memories together in Sub-Optimal, today’s must-play multiplayer adventure. Can you survive the ocean’s darkest secrets and emerge as party legends?

How to Play

Getting started in Sub-Optimal is simple but calls for smart teamwork! First, ensure you and at least one other player are at different computers—this wildly fun adventure is online-only and thrives on coordination. Head to the Sub-Optimal itch.io page, create or join a lobby, and connect by sharing the provided room code.

Once onboard your submarine, roles are up for grabs! Players can take the helm to steer, control the cannons and drills for defense and clearing obstacles, manage the sonar to scout unraveling dangers, operate the map to plot your course, or hold the shield against incoming threats. Rotate tasks as you wish, as the game encourages dynamic switching in the heat of action.

All controls are conveniently keyboard-based (check the settings for key bindings). Coordination is vital: announce your intent in the built-in chat or hop onto the official Sub-Optimal Discord for high-energy voice banter.

Progress through four stages filled with shifting perils and mini-bosses, culminating in a legendary face-off against the Kraken. Collect quirky power-ups, dodge environmental hazards, and collaborate to patch up damage.

Beginner Tips:

- Divide roles based on each player’s strengths

- Keep communication flowing—solo play isn’t possible!

- Regularly swap roles to keep everyone engaged

- Prioritize upgrades and repairs mid-mission

With every session, master efficiency and synergy for maximum fun—and glory.

Controls

mouse
keyboard

Tips & Tricks

  • Constantly communicate! Use voice chat for the fastest, clearest teamwork.
  • Assign roles but rotate often to adapt to rapidly changing threats.
  • Use sonar frequently to reveal hidden dangers and plan ahead.
  • Prioritize shields during boss fights—timed defense can save your crew.
  • After defeating a boss, scavenge the area for power-ups before advancing.
  • Master quick repairs—damage can spiral out of control fast if ignored.
  • Coordinate special abilities and gadgets—timing is everything in tough moments.

Game Features

  • Chaotic 2-4 player online co-op exclusively focused on teamwork
  • Browser-based and completely free—no downloads required
  • Vibrant indie visuals and lively sound design for immersive play
  • Engage in four hand-crafted levels, each with a dramatic boss battle
  • Unique submarine controls—rotate between pilot, cannons, drills, shield, sonar, and map
  • Dedicated Discord for seamless voice chat and community events
  • Replayable challenge: every playthrough brings new comedic chaos

Frequently Asked Questions

Can I play Sub-Optimal solo or with AI teammates?

No, Sub-Optimal is designed strictly for 2-4 real online players. You’ll need at least one other person (on another computer) to play.

Is Sub-Optimal compatible with mobile devices or tablets?

Currently, the game is built for HTML5 desktop browsers and does not support mobile or tablet play. For the best experience, use a desktop or laptop.

How do I communicate with my team during gameplay?

The game features built-in text chat, but for peak coordination and hilarity, join the official Sub-Optimal Discord server for real-time voice chat.

What happens if a teammate disconnects mid-game?

If a player loses connection, the team is left shorthanded, increasing the challenge. Try to reconnect quickly or restart the mission for a balanced crew.

Are there any in-game purchases or ads?

No! Sub-Optimal is 100% free to play with no ads or microtransactions. Enjoy a pure, uninterrupted adventure with your friends.

Game Info

Rating 3.8/5
Plays 12,125
Category adventure
Difficulty easy
Mobile No
Haunted

Haunted

Grotesqueresque

Grotesqueresque

D-List Diva

D-List Diva

Coop Catacombs: Async Multiplayer Roguelike

Coop Catacombs: Async Multiplayer Roguelike

Dating Killmulator

Dating Killmulator

Lookouts

Lookouts

Exhibit of Sorrows

Exhibit of Sorrows

Learn Godot's GDScript From Zero

Learn Godot's GDScript From Zero

Cantata

Cantata

purrgatory

purrgatory

Honey Trap: Burned

Honey Trap: Burned

BLACK OPIUM prologue

BLACK OPIUM prologue

Confidential Killings

Confidential Killings

I Didn't Cheat

I Didn't Cheat

Melanie and the Magic Forest

Melanie and the Magic Forest

Island Of Mine (beta)

Island Of Mine (beta)

Arcane Earth - Increment Clicker

Arcane Earth - Increment Clicker

Silent Bonds

Silent Bonds

We Suspect Foul Play

We Suspect Foul Play

Open Saber

Open Saber

Fetch Quest (Game Jam Version)

Fetch Quest (Game Jam Version)

Seedship

Seedship

Noia Online [Alpha]

Noia Online [Alpha]

Zorlok

Zorlok

Fire and Dice

Fire and Dice

Social Democracy: An Alternate History

Social Democracy: An Alternate History

The King's Hound

The King's Hound

Ranfren:  Not Lucid Swap

Ranfren: Not Lucid Swap

Good Morgan Eve

Good Morgan Eve

Pre-Odyssey: Odysseus, Penelope & her Ducks [Otome; NaNoReno Version]

Pre-Odyssey: Odysseus, Penelope & her Ducks [Otome; NaNoReno Version]

Mind Games: Obsession

Mind Games: Obsession

Stygian Sun: Total Eclipse IF

Stygian Sun: Total Eclipse IF

Cargo

Cargo

The Adventures of Sherlock Holmes - An Affair of the Heart

The Adventures of Sherlock Holmes - An Affair of the Heart

Moonlight

Moonlight

Unraveled

Unraveled

Godly Heritage Quiz

Godly Heritage Quiz

M's Cases | Chapter 1

M's Cases | Chapter 1

Misplaced

Misplaced

Solitomb

Solitomb

Another Night at the Archive

Another Night at the Archive

Tales of Misteria

Tales of Misteria

IF - Mafiafell

IF - Mafiafell

"And I'll Never Leave"

"And I'll Never Leave"

Incredibox Sprunki Pyramixed

Incredibox Sprunki Pyramixed

Dream Diary

Dream Diary

FarAfter

FarAfter

Bru & Boegie: EPISODE 1 – Get da MILK!

Bru & Boegie: EPISODE 1 – Get da MILK!

RunieStory - Gameboy color / Analogue Pocket

RunieStory - Gameboy color / Analogue Pocket

Download RAM Idle

Download RAM Idle

The Lonesome shooter : A Father's Retribution

The Lonesome shooter : A Father's Retribution

Decline

Decline

The Marked

The Marked

Fall from Space (Game Boy)

Fall from Space (Game Boy)

Ciao Nonna

Ciao Nonna

Dragon Sweeper

Dragon Sweeper

Bedrot

Bedrot

i had another dream about you last night

i had another dream about you last night

Yume Tenshi 夢天使

Yume Tenshi 夢天使

nekoneko RPG

nekoneko RPG

HARVEST 2300

HARVEST 2300

Theropods - Demo

Theropods - Demo

Mad Science Interactive: Evil Embryology

Mad Science Interactive: Evil Embryology

Star Word: a Scrabble-like Adventure

Star Word: a Scrabble-like Adventure

Knight Night

Knight Night

BROCCOLI QUEST II: THE DARK SACRAMENT

BROCCOLI QUEST II: THE DARK SACRAMENT

Night Flyer - A Bat’s Journey

Night Flyer - A Bat’s Journey

SYNTAXIA

SYNTAXIA

O, Your Heavenly Stars!

O, Your Heavenly Stars!

Mezma's Revenge

Mezma's Revenge

Something is wrong with my World Map

Something is wrong with my World Map

Crash Course in You

Crash Course in You

stay with me

stay with me

soundStrider

soundStrider

Aria's Choice

Aria's Choice

Maia

Maia

On Wings Bringing Sleep

On Wings Bringing Sleep

Defiled Hearts: The Barbarian (alpha demo)

Defiled Hearts: The Barbarian (alpha demo)

ID Card [AI Remake]

ID Card [AI Remake]

Overnight

Overnight

Drown the Bride

Drown the Bride

Berrywitched!

Berrywitched!

Things Are Grim

Things Are Grim

Explore MakeGame

Explore MakeGame

Butterfly Soup 2 Web & Android Ports

Butterfly Soup 2 Web & Android Ports

Graveyard Oracle

Graveyard Oracle

80s Ford Game - Day 0 + Day 1 Demo

80s Ford Game - Day 0 + Day 1 Demo

Sailing with Stans (DEMO)

Sailing with Stans (DEMO)

Remnants Of The Past - Act 2

Remnants Of The Past - Act 2

Happiness Inc.

Happiness Inc.

GBVR - Virtual Trader

GBVR - Virtual Trader

Barback Blues: A Valhalla Story ~鬱陶しき日々~

Barback Blues: A Valhalla Story ~鬱陶しき日々~

Dante's Detour - Chapter I

Dante's Detour - Chapter I

(OPEN SOURCE) Tetris.html

(OPEN SOURCE) Tetris.html

Volatile Memory: Blood Trail

Volatile Memory: Blood Trail

Tourist Trap

Tourist Trap

Hauntsfield

Hauntsfield

Scale Salon

Scale Salon

Chantey - DEMO

Chantey - DEMO

A Taste of the Past

A Taste of the Past

Myosotis

Myosotis

Kity Builder (Prototype)

Kity Builder (Prototype)

Dungeon Raid

Dungeon Raid

Bubble Dreams 3D

Bubble Dreams 3D

Stake Through A Bloody Heart

Stake Through A Bloody Heart

Astro Gets A Snack at 2:34 AM | Playable Engine

Astro Gets A Snack at 2:34 AM | Playable Engine

And You'll Miss It

And You'll Miss It

4x4 Archipelago

4x4 Archipelago

Antlers

Antlers

Mister Jack - ScreamJam2024

Mister Jack - ScreamJam2024

Makin Biscuits

Makin Biscuits

Lowland Keepers

Lowland Keepers

Isletography

Isletography

Baldi's Gameboy All-Stars V3.0.5c

Baldi's Gameboy All-Stars V3.0.5c

BLOODSONG

BLOODSONG

Goblins Demise

Goblins Demise

Slay the Lizard of Lunenberg! (and other thankless sidequests)

Slay the Lizard of Lunenberg! (and other thankless sidequests)

Cow Life Sim RPG

Cow Life Sim RPG

The Giant's Visit 1.1

The Giant's Visit 1.1

Sebastian's Quest

Sebastian's Quest

Shadow Hunter (Amstrad)

Shadow Hunter (Amstrad)

Tutankham

Tutankham

Behind the Green Door

Behind the Green Door

shutdown.

shutdown.

Midnight Idle

Midnight Idle

TUNIC GBC

TUNIC GBC

Friend of the Void

Friend of the Void

Longest Night

Longest Night

The Snowperson [Demo, Winter VN Jam 2021]

The Snowperson [Demo, Winter VN Jam 2021]

Oni

Oni

Julia Was Alone (Chapter 4)

Julia Was Alone (Chapter 4)

The founders of [redacted]

The founders of [redacted]

Withering Hour

Withering Hour

iro

iro

The 14th Axe Wound

The 14th Axe Wound

Confluence: An Of Sense and Soul Soliloquy [EN/日本語]

Confluence: An Of Sense and Soul Soliloquy [EN/日本語]

Little Dungeon Renovator

Little Dungeon Renovator

zone: a history

zone: a history

Girls' Day Out

Girls' Day Out

A dark winter wander

A dark winter wander

Gorf the Ghost Saves Halloween

Gorf the Ghost Saves Halloween

The Advisor's Game

The Advisor's Game

Event Horizon

Event Horizon

Squeaks & Squalls

Squeaks & Squalls

After the Janazah

After the Janazah

Hamster Shelter

Hamster Shelter

Cubito McRadio & Dr.Isosceles - Prologue

Cubito McRadio & Dr.Isosceles - Prologue

Bunbons

Bunbons

Traced In Ink

Traced In Ink

Little Space Rangers

Little Space Rangers

Happy Dawn

Happy Dawn

Download RAM Idle 2

Download RAM Idle 2

Tech and Blood

Tech and Blood

Coria and the Sunken City

Coria and the Sunken City

Drifting Among Worlds

Drifting Among Worlds

Congee

Congee

CaliforniaClan

CaliforniaClan

GBJam10 - Potbound

GBJam10 - Potbound

A Fond Farewell

A Fond Farewell

Sofia the Witch Curse of the Monster Moon - Demo

Sofia the Witch Curse of the Monster Moon - Demo

The End of Decay

The End of Decay

The Daughters of the Sun

The Daughters of the Sun

Stevedore (MSX, 2020)

Stevedore (MSX, 2020)

Kudzu

Kudzu

Peter Stinger, Scorpion Ethicist, learns about himself and others

Peter Stinger, Scorpion Ethicist, learns about himself and others

BIRLA

BIRLA

sprunki unblocked free no virus! mini update 2!

sprunki unblocked free no virus! mini update 2!

PowerPutt Legend

PowerPutt Legend

Billy Went to a Carnival

Billy Went to a Carnival

Borbo's Quest

Borbo's Quest

Resident Evil:GB

Resident Evil:GB

Faceless Date

Faceless Date

TREES' ADVENTURE - Demo

TREES' ADVENTURE - Demo

Fatal Focus

Fatal Focus

Momotarou

Momotarou

Engineering Marvels From Hell

Engineering Marvels From Hell

Lil Flutie 3D - Director's Pandemic Edition

Lil Flutie 3D - Director's Pandemic Edition

Spooksville, USA - the sequel to HECK HOUSE

Spooksville, USA - the sequel to HECK HOUSE

Arcane Beak

Arcane Beak

Messages

Messages

The Time Has Come

The Time Has Come

ZENO 4/1

ZENO 4/1

Adventures In BreezeClan - A Tale Begins

Adventures In BreezeClan - A Tale Begins

Pixl Patches

Pixl Patches

The Story of Sin

The Story of Sin

Fairytale Thief: Sleeping Beauty

Fairytale Thief: Sleeping Beauty

ZOZ

ZOZ

Crossing Lines

Crossing Lines

I Can Still Be A Hero

I Can Still Be A Hero

Perfumare DATING GAME

Perfumare DATING GAME

PIXEL CONQUEST

PIXEL CONQUEST

The Last Astronomer

The Last Astronomer

The Last of the Lords of Ice

The Last of the Lords of Ice