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Watch trailer on Steam ↗Happy Nuclear
Hi-Develop · Published by Hi-Develop
Positive — 89% positive (18 reviews) · 7 achievements
Last updated 28 Sept 2026
Happy Nuclear is an evidence-based investigation game where players act as detectives to prevent a disaster. They analyze interconnected case information on an investigation board, primarily using old CCTV and access logs. Cases link together at the end, and each replay introduces changes.
£4.29
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Price history
Indie, RPG, Simulation, Casual · 2025 · More under £5 games
Discover clues and prevent disasters as a detective in Happy Nuclear, an engaging RPG where every replay brings new challenges. Analyze CCTV and logs to solve puzzles in this simulation game from Hi-Develop.
About this game
Happy Nuclear
Happy Nuclear is a challenging puzzle investigation game that tests your thinking skills. Players take on the role of a detective who becomes involved with a terrorist organization planning to destroy the world with nuclear bombs. You must use logic and problem-solving skills to investigate and stop this organization before it's too late.
Gameplay Mechanics
Players need to identify the culprits by piecing together incomplete information to reconstruct a complete picture of events at the crime scene. The game system feels similar to Sudoku, but instead of filling in numbers, you're creating movement patterns of suspects at the crime scene.
In-Game Information Sources
"CCTV Smart Detection System" - This system provides partial information about who used rooms at specified times.
"Room Usage Log" - This system provides partial information about how many times a specified suspect entered this room.
Game Rules (Golden Rules)
Happy Nuclear has 2 fundamental rules that apply throughout the game:
Everyone must move only to adjacent rooms - skipping rooms is not allowed.
No one can stay in the same room for more than 1 hour.
Hotkeys make gameplay more fun
Press number keys 1-0 to pull out tokens and tools.
Press Delete to remove tokens and tools.
Copy and paste tools with Ctrl+C / Ctrl+V.
Quick access the applications: Press 'Q' to open logs, 'W' to open CCTV
System Requirements
Will my PC run this? →Minimum
- Requires a 64-bit processor and operating system
- OS: Windows 10 and later
- Processor: 2.5Ghz or better
- Memory: 2 GB RAM
- Graphics: Support for OpenGL 3.3
- Storage: 1 GB available space
Recommended
- Requires a 64-bit processor and operating system
- Memory: 4 GB RAM
Supported Languages
Latest news
Patch NotesOfficial
V 0.2.9 Temporary Fix
We've received reports about an issue where floorplans automatically pull tokens to unwanted positions when loaded, which ends up destroying the progress players have worked hard to build. Originally, this feature was designed to make things easier by letting players move floorplans along with their tokens to different locations. However, it seems like it's causing more trouble than convenience for our players. I think we need to go back to the drawing board and redesign this feature. In the meantime, to keep the game playable, we've temporarily disabled this system.Read full article on Community Announcements (Eit)Patch NotesOfficial
Hot fix V 0.2.8
Bug Fixes: Fixed an issue where cases would not randomize properly when the player restarted the gameRead full article on Community Announcements (Eit)Patch NotesOfficial
Update Notes For June 12 (Version 0.2.7)
V 0.2.7 Fixed unclear English translation in the tutorial section Added hotkeys for quick access: Press 'Q' to open logs, 'W' to open CCTVRead full article on Community Announcements (Eit)Patch NotesOfficial
0.2.6
Fix token spawning in wrong position.Read full article on Community Announcements (Eit)Patch NotesOfficial
V 0.2.5 Add SFX and BGM options
Add SFX and BGM options Fix some SFX not syncing with inputRead full article on Community Announcements (Eit)






