Casualties: Unknown for PC: Download, Mods & Requirements

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Casualties: Unknown on PC. Click to open it full size.

Casualties: Unknown is a hardcore 2D survival game for PC from Orsoniks, available on Steam. You are a test subject dropped into the caves of an alien planet to bring back lost cargo. You dig, climb, scavenge and craft your way down, one layer at a time.

What makes it different is your body. Every limb, wound and heartbeat is simulated, so you bandage cuts, pull out shrapnel, fight infections and stop bleeding by hand. Your mood matters too, and a character who loses hope gets harder to keep alive.

The full game came out on November 9, 2026, after a free demo that publisher Oro Interactive says more than 500,000 players tried. It runs on 64-bit Windows 10 and 11, plays with mouse and keyboard, and comes in English and Simplified Chinese.

Already down in the caves? Tell us the deepest layer you have reached. Got questions before buying? Reach out to us directly.

What You Need to Know

It is a full release, not Early Access. All 11 layers, three characters and the endings are in.
A free demo with the first five layers is on Steam.
It is sold on Steam only. It is not on the Epic Games Store or GOG.
It is single-player. Co-op exists only as a fan mod.
It runs on almost any PC: Steam asks for a Core i3 laptop chip and 500 MB of space.
It deals with heavy themes, including depression and self harm.

Table of Contents

Quick Facts

The player creature fleeing a hostile animal through a dark purple cave filled with giant glowing mushrooms

Get the Game:

Buy on Steam Check on Boosteroid

Price	$22.99
Released	November 9, 2026
Developer	Orsoniks
Publisher	Oro Interactive
Genre	2D survival, psychological horror
Players	Single-player
Store	Steam (free demo available)
Platform	Windows 10/11 (64-bit)
Controls	Mouse and keyboard
Languages	English, Simplified Chinese
Mods	Nexus Mods (BepInEx)

How to Download Casualties: Unknown on Windows

Casualties: Unknown is on Steam only. It is a small download, well under 1 GB.

Step 1. Install Steam. Get Steam and sign in.
Step 2. Open the store page. Go to Casualties: Unknown on Steam.
Step 3. Buy the game. Click Add to Cart and check out.
Step 4. Install it from your Steam library.
Step 5. Launch it and play the basics course before your first run.

Want to try it first? The free demo installs the same way and has the first five layers.

Casualties: Unknown Price and Editions

Casualties: Unknown costs $22.99 on Steam, with regional pricing in other countries. There is one edition, and it is the whole game.

The only add-on is the Casualties: Unknown Soundtrack for $9.99, made by Orsoniks. It has more than 50 tracks and runs over three hours, as MP3 files. Steam also sells a bundle of the game and the soundtrack together. The soundtrack is a way to support the developer and adds nothing to the game itself.

💡 Your PC is too weak? Cloud gaming is an option. Check on Boosteroid.

What Is Casualties: Unknown?

Casualties: Unknown drops you on a hostile planet as one of thousands of test subjects. Your captors want their lost cargo back, so they send you down into a cave system with 10 main layers, a shorter 11th layer and an optional bonus ending. No one before you has made it back up.

The world is a side-on 2D cave you can dig through, climb and blow apart. Each layer has its own dangers: hostile animals, traps, radiation, flooding and the machinery that earlier expeditions left behind. Old pods and caches hold good loot, but some of it can kill you just as easily as it helps.

The health panel tracks every limb, your blood, your heart rate and your stats.

Injuries are where the game lives. A deep cut keeps bleeding until you bandage it, a dirty wound gets infected, and losing enough blood knocks you out. The heart is simulated too, so blood pressure, heart rhythm and drugs all affect each other. Lose a limb and you can replace it with a prosthetic, and the best tier is better than the original.

Bandaging is a hands-on minigame: drag the dressing around the wound to stop the bleeding.

Your mind is the other half of survival. Your character reacts to pain, hunger and fear, and low mood makes everything harder. Between those two systems, every run turns into a story about how far you can push one fragile body. Finish a run and you unlock the next of the three playable characters, each with their own stats and quirks.

Official Trailer

Watch the official release date trailer for Casualties: Unknown to see the cave layers, the injury system and the creatures you meet on the way down.

Key Features

A fully simulated body

Every limb can be cut, broken, infected or lost, and your heart and blood are simulated in detail.

Mood that changes the game

Your character reacts to what happens to them, and despair makes survival harder.

Crafting from what you find

Turn cave plants and scrap into bandages, medicine and tools, from more than 300 items.

11 layers to descend

Each layer brings new dangers, from traps and radiation to flooding and hostile wildlife.

Three characters, several endings

Unlock new species by finishing runs, and reach different endings depending on how deep you go.

Runs your way

Presets and sliders for loot and danger, plus an endless mode after the story.

Is This Game for You?

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Our Take

🎮 Our Take

Casualties: Unknown is one of the most detailed injury systems we have seen in a survival game, and it fits inside a small pixel art cave crawler. That contrast is the hook: a cute-looking creature whose blood pressure, infections and mental state you manage like a field medic. Three years of work by one developer show in how many systems connect. The flip side is a steep learning curve and runs that can end after an hour of progress, and the heavy themes are not just decoration.

If you like hardcore survival and do not mind dying a lot, buy it, since the full game doubles the demo and adds the endings. If you are unsure, play the free demo first: it has the same core systems, so it will tell you quickly whether the medical side clicks for you. If you want co-op or a controller game, this is not it without mods.

System Requirements

Casualties: Unknown is a light 2D game. Steam lists only a minimum spec: 64-bit Windows 10, a Core i3-8130U laptop processor and 500 MB of space. There is no separate recommended spec and no listed graphics card, so integrated graphics should be fine.

Casualties: Unknown PC Requirements

Minimum spec, as published by the developer on Steam

Component	Minimum
OS	Windows 10 (64-bit)
Processor	Intel Core i3-8130U 2.20 GHz
Storage	500 MB available space
Screens	16:9, 16:10 and ultrawide supported

Thinking of a gaming PC for heavier games? See our Best Gaming Desktops guide.

Tips for Beginners

Play the courses first

The basics course teaches movement, eating and treating wounds. The First Aid course opens once you reach layer 2, and Crafting once you reach layer 3.

Stop bleeding right away

Blood loss is what kills most new players. Bandage a cut as soon as it happens, before you black out.

Keep your mood up

A miserable character performs worse. Eat, sleep and avoid needless pain to keep their spirits from crashing.

Hold Left Control

It shows the labels of every item nearby, which makes it much easier to spot loot in a messy cave.

Tune your first run

Use the run settings on the main menu to raise loot or lower danger while you learn. There is no shame in it.

Best Casualties: Unknown Mods to Start With

Casualties: Unknown has a busy modding scene that started during the free demo. There is no Steam Workshop: mods live on Nexus Mods, and most of them need BepInEx (a free mod loader for Unity games) installed first. All four mods below have been updated for the full release.

Casualties Together

Co-op

By CasTogetherDev

Turns the game into online co-op. You host or join through Steam lobbies, talk over in-game voice chat, point at spots for your friends and heal each other. It runs on its own lobbies, separate from any official servers.

View it on Nexus Mods

QoL Unknown

Quality of life

By Jimmyking

An all-in-one comfort mod. Its headline feature is saving in the middle of a layer, plus autosaves, seeded runs, inventory sorting and quicker item transfers. Every feature has its own toggle.

View it on Nexus Mods

Custom Structures

New content

By Jimmyking

Adds more than 1,200 player-made structures to the caves, each with its own loot and dangers. It also comes with a browser-based editor if you want to build and share your own. It needs CUCoreLib.

View it on Nexus Mods

Alexx_’s Medical Brutalism

Harder

By AlexandrBud

For players who find the base game too gentle. It adds dozens of new medical problems, from collapsed lungs and fevers to frostbite, parasites and blood types, along with the items to treat them.

View it on Nexus Mods

💡 These are fan-made mods, not official ones. Many older mods on Nexus were built for the demo, so check that a mod says it supports the full release before you install it. The game has no anti-cheat, so mods carry no ban risk, but a game update can break them until their authors catch up. If the game acts up, remove the BepInEx folder and use Steam’s Verify Integrity of Game Files option.

Casualties: Unknown Screenshots

The inventory wheel, a hungry run in a dim cave, a crystal cave trader and what it looks like when your character starts to pass out. Click any image to open it full size.

: Casualties unknown inventory wheel from

: Casualties unknown hungry cave from

: Casualties unknown crystal cave from

: Casualties unknown blurred vision from

Casualties: Unknown FAQ

Is there a free Casualties: Unknown demo?

Yes. The free demo is on Steam and covers the first five layers with all the core systems. The developer has said the demo will not get new updates, so the full game is the only place to get layers 6 to 11, the endings and the extra characters.

Does Casualties: Unknown have co-op or multiplayer?

No. The game is single-player only. A popular fan mod called Casualties Together adds online co-op through Steam lobbies, but it is not official, so expect the odd bug after game updates.

Can you make Casualties: Unknown easier?

Yes. The run settings on the main menu have presets and separate sliders for things like loot and danger, so you can make a first run gentler. The full game also adds an endless mode for players who want to keep going.

Is Casualties: Unknown suitable for younger players?

Probably not. The developer warns that the game touches on depression, violence, dismemberment, drug use and self harm, and your character reacts to what happens to them. The art is cartoon pixel art, but the themes are heavy.

Does Casualties: Unknown support controllers?

Steam does not list controller support for the game. Plan on playing with a mouse and keyboard, since the inventory, crafting and bandage minigame are built around the mouse.

Is Casualties: Unknown on Epic, GOG or consoles?

No. On PC it is sold on Steam only, and it is not on the Epic Games Store or GOG. Only a Windows version has been released.

What are the Casualties: Unknown system requirements?

Steam lists 64-bit Windows 10, an Intel Core i3-8130U processor and 500 MB of free space as the minimum. It is a light 2D game, so most PCs and laptops from the last several years can run it.