Player reviews: 0% positive0 reviews
Runs on: Windows

Where to get it

2026 · Adventure · Indie

Casualties: Unknown

Casualties: Unknown is an unforgiving cave-exploration survival simulator. Your captors have tasked you with retrieving lost cargo on a foreign planet, explore its 5 layers and do your best to survive diverse hostile environments. You are just one of the thousands of test subjects sent to die.

Released: 2026
Platforms: Windows
Genres: Adventure Indie Simulation Survival
Developers: —
Publishers: —
Perspective: Side view
Themes: Action Science fiction Horror Survival
Languages: Arabic, Chinese (Simplified), Czech, English, French, German, Korean, Polish, Portuguese (Brazil), Russian, Spanish (Mexico), Ukrainian

About

Casualties: Unknown, also known by its former name Scav Prototype, is an upcoming survival video game developed by indie developer Orsoniks and published by Oro Interactive. A playable demo became available on Steam on April 20, 2026. The game scheduled to be released on November 9th, 2026.

The players play as an Experiment, a test subject sent down to the depths of an alien planet to retrieve lost cargo. The game revolves around navigating and safely descending the planet's cavernous layers while avoiding and treating injuries, hunger, and thirst. The game centers around complex health systems and difficult resource management, challenging players to avoid death in numerous ways as they go as far down as they can while making their way to the final objective of the game, a piece of high value cargo mistakenly sent to the game's setting, The Grey Planet.

›Story

Humanity has technologically progressed significantly. Things that seemed impossible before were now commonplace.

At the center of it was one company. Their progress seemed miraculous, but they guarded their secrets closely.

Years ago they had created a new species: a combination of animal and human DNA they simply called "Experiments."

These experiments were the perfect test subjects, close enough to humans, but theirs to do with as they pleased. They toiled over them, twisting their biology even further to suit their needs, and as the years went by, the population only increased.

None would ever see the outside.

Now it seemed that the Earth could no longer contain their ambitions. With their newly devised teleportation technology, they set their sights on a gray planet teeming with life.

Soon enough, tons of miscellaneous cargo and trash was sent.

Due to calibration difficulties, just as much ended up in the planet's cave system as on the surface, but the project progressed smoothly.

That was, until an unknown error caused an important piece of technology to be sent deep into the caves instead.

Soon enough, the scientists had devised a plan. A plan with little risk to themselves.

The chance of success were low, but their living fodder was plenty.

You are one unfortunate specimen.

Resistance is not an option.

Players say

Media

The articlegameplay, story, development, reception

Gameplay

Casualties: Unknown is a cave-exploration survival game in which the player controls a captive test subject called an Experiment placed on a hostile alien planet and tasked with retrieving lost cargo sent by a futuristic and spacefaring version of the human race. The full game is planned to include eleven procedurally generated underground "layers" of increasing difficulty; the public demo makes five of these layers available, and upon release of the full game, 6 more layers will be available. The game features a simulated limb and cardiovascular system, requiring the player to bandage wounds, treat infections and manage blood loss to avoid losing consciousness. The player character's mental state is also tracked as a survival mechanic alongside physical injury.

Too low mood can cause self-harm events of various severity, varying from lightly clawing their own arm to ripping out their own eye. The health system emphasizes the fact that the only "game over" condition is the player's brain health reaching zero, not any other organs.

Development

Casualties: Unknown is developed by Orsoniks, described in a publisher press release as a designer, programmer, composer and artist. The game began as a small personal project that gained a wider following after early alpha builds were distributed for free on the platform itch.io, with the publisher reporting that the game had surpassed 300,000 players on that platform prior to its Steam debut. The game is built using the Unity engine.

The first public build of Casualties Unknown was released on itch.io on January 1, 2025, under the placeholder name Scav Prototype.

Reception

Casualties: Unknown received a largely positive response on the basis of its free demo. Games outlet GamingBible described the demo as "brutally difficult but emotionally gripping" and reported that it had drawn an "overwhelmingly positive" Steam user-review rating despite the game having little prior public profile, noting that user reviews singled out its damage-simulation and physics systems for praise while citing its difficulty as the main point of criticism. Rock Paper Shotgun published a piece comparing the game to Noita. Writing for OpenCritic in a piece syndicated from TheGamer, journalist Josh Coulson identified Casualties: Unknown as the highest-rated demo of more than 8,500 available during the June 2026 Steam Next Fest, citing a score of 93.08 percent based on user reviews tracked by SteamDB, and described its core loop as combining cave exploration with the board game Operation. GamingOnLinux also rated the demo positively, calling its exploration and injury systems intense, though it noted that the user interface needed further work.