Cyan Brain is a sci-fi horror adventure from NEKOUJI STUDIO, built in Unity and presented with animated 2D visuals. You play a female protagonist who is chased by futa monsters and other creatures, with graphic violence and adult content included. The game features horror, monster girl, and futa/trans themes, combining pursuit and adult content in a Japanese-made setting.
The current build is version 1.1.4, released January 5, 2026, and development is ongoing. It runs on Windows in English and is censored. This update officially added achievements, added shower scene sounds with HS202, repaired incomplete enemy illustrations, fixed collectible unlocking through Cloud Saves, and corrected a UI crash. Earlier changes included a respawn fix after saving, minor numerical adjustments, small bug fixes, and Korean support, while saving problems remain under active investigation.
Developer's description
Cyan Brain is a sci-fi horror game where players run and are pursued, by futa monsters and more....
Before downloading, please be aware
Please note that the game contains graphic violence and adult content.
v1.1.4
Thank you all for your patience! Achievements for Cyan Brain are now officially live.
We have also implemented the following fixes and updates:
Added sounds for the shower scene with HS202.
Fixed enemy illustrations where the uncensored assets were incomplete.
Fixed an issue where collectibles were not unlocking correctly via Cloud Saves.
Fixed a UI bug that could cause the game to crash.
v1.1.3 Hotfix
Fixed an issue where respawning after saving would still place the player back at the beginning of the level.
The saving issue is still under active investigation and repair. If you encounter any other related issues, please report them in the discussion forum.
v1.1.2
Minor numerical adjustments and small bug fixes
Added support for the Korean version
v1.1.1
Bugfixes
v1.1.0
New Dynamic CG Added (Unlockable After Clear)
2 New Monsters (Appear in Chapters 4 & 5 / Defeat Cutscenes Included)
2 New Weapons (Obtainable in Chapter 3 / Placement Changed)
Mine System Implemented (G Key Deployment / Self-Destruct Mechanism Included)
1.01
New Additions
Added 3 new reward CGs
┗ Unlocked after clearing Stage 2, Stage 3, and Stage 4
┗ Already-cleared save data can directly view them
Difficulty Adjustment
Made Easy Mode even easier to clear
Weapon Adjustment
Improved performance of certain weapons
Map Improvements
Adjusted layouts of certain maps
Bug Fixes
(1) Fixed issue where collected battle data would be lost if the protagonist died
(2) Fixed issue where protagonist would not appear at the correct location after loading a save
(3) Fixed freeze issue when re-entering Stage 2 and talking to HS202
(4) Fixed random crash issues
(5) Fixed freeze when opening doors in maps
(6) Fixed issue where some enemies would freeze in maps
(7) Fixed issue where protagonist could still roll during NPC dialogue
(8) Fixed incorrect UI display when restoring HP
(9) Fixed missing collision in some map areas
(10) Fixed negative ammo count issue
2025-08-13
Full Release
Demo 4.0
N/A
Demo 8.1
Base/Story System/Content Update
Demo 6.14
♦ New weapons
♦ A device for replenishing ammunition
♦ A feature to expand the field of view
♦ Several new screen effects
*Please note that save data from the previous version will no longer be usable.
**Please be aware that this version is a test release and may contain bugs that could affect the gameplay experience. We appreciate your understanding and valuable feedback.
Ch.01 Test Demo
Dear followers, thank you very much for your continued support.
After much hard work, we are pleased to announce that the test version of Chapter 01 of [CYAN BRAIN] is now complete. We have uploaded the game content files so that our sponsors can play it.
Due to time constraints, the story and dialogue content within the game have not yet been implemented. We plan to update the scenario system in the game by next month.
This update includes the prologue map and related gameplay content, as well as new scenes, monsters, traps, and a boss.
There is a possibility that the game save data may contain bugs. If you encounter any issues with the save data, please delete it and create a new save to play.
The current version is a test version and may contain bugs that affect the gameplay experience. We appreciate your understanding and valuable feedback.
The content to be added in the next update includes the following:
△ Dialogue and collectible items for Chapter 1 to deepen the understanding of the story
△ New NPC characters
△ Many more new weapons
△ Base system update, allowing various activities at the base
△ Addition of an animation viewing mode
Player reviews
Player rating3.0 / 5 · 20 ratings
Written reviews20 · avg 3.3★
Positive (4–5★)40%
Latest review2026-03-22
What players say
Mixed reception: strong art and gore appeal, but repetitive combat and excessive violence draw criticism.
5★5
4★3
3★7
2★3
1★2
Players like
Strong art, visuals, lighting, and smooth animations
Gore and ryona scenes are varied and well executed
Fun gunplay and responsive controls
Common complaints
Repetitive, basic combat with little variety
Excessive gore cannot be reduced and turns some players off
Sexual content is limited compared with gore
Best for players who enjoy gore-focused adult games with strong art and shooting.
Summarised from 20 written player reviews.
shujuku2026-03-22★★★★★
The game is good and does its genre well except that it does not let me do one thing. I literally cant disable the excess amount of gore and therefore I literally cant give it any rating higher than 3…
ZuVres2026-03-17★★★★★
It's an okay game overall. The level design is very hallway-like, with only a few platforming segments here and there. Most enemies can be skipped, and bosses can usually be defeated using mines (or mostly mines), except for 2 of…
Fareld2026-03-06★★★★★
Straightforward side-scrolling shooter but still fun to play, with a cute protagonist, good visuals, the executions are quite creative, some enemies have decent design. It's quite repetitive though, some weapons feels like they're fillers and I wish there was a…