ROOM 01
Hyejin's first hidden trace
A message on the wiped glass proves that she passed through this room first.
EPISODE 01 · NOW AVAILABLE
THE ROOM THAT
DOES NOT EXIST, 404
An abandoned escape-room game has begun again in the real world.
Follow Hyejin's trail and escape all five spaces.
- GENRE
- MYSTERY · ESCAPE ROOM
- PLATFORM
- PC · MOBILE WEB
- PRICE
- FREE TO PLAY
EPISODE 01 · THE MISSING HYEJIN
SOMEONE RECREATED
HYEJIN'S 404.
No one knows who revived the game or why participants are being summoned. Only one thing is certain: the devices inside do not forgive failure.
ROOM 03
The corridor where the trail ends
ROOM 05
The final choice
ROOM 404 · EPISODE ROADMAP
FIVE EPISODES
ARE CURRENTLY PLANNED.
EPISODE 01 is free to play now. EPISODES 02 through 05 form one continuous story, gradually revealing every secret behind Hyejin and ROOM 404.
EPISODE 02 · IN DEVELOPMENT
SOMEONE'S INVITATION
After Hyejin's trail disappears, a new invitation arrives. The second round begins inside a much larger experimental facility.
EPISODE 03 · IN DEVELOPMENT
REPLICATED MEMORIES
Records left by different participants begin to connect, revealing the purpose behind the copied ROOM 404.
EPISODE 04 · IN DEVELOPMENT
THE OBSERVER'S ROOM
The moment you believe you are watching someone else, you discover that the observer has been tested all along.
EPISODE 05 · IN DEVELOPMENT
THE FIRST 404
The origin of every replica. The reason Hyejin created and abandoned ROOM 404—and why she chose to pursue them—is finally revealed.
ROOM 404 · OFFICIAL ARCHIVE
READ THE RECORDS
BEHIND THE ROOMS.
Explore the public world guide, spoiler-free episode notes, puzzle design, environment production, sound design, and play documentation created by Red Castle Studio.
STORY & WORLD
01
WORLD ARCHIVE
The public history of Hyejin, the copied rooms, and five connected episodes.
02EPISODE 01
A spoiler-free route through the five spaces of The Missing Hyejin.
03EPISODE 02 PROGRESS
What is confirmed, what is being built, and how the next round will change.
MAKING ARCHIVE
04
PUZZLE DEVLOG
How rules, hints, and difficulty are tested before a puzzle reaches players.
05ENVIRONMENT DEVLOG
Building cinematic rooms that remain readable and playable on mobile.
06SOUND DEVLOG
Layered ambience and immediate feedback that communicate room state.
DEEP DIVE
07
HINT SYSTEM DEEP DIVE
Why fixed answer lines failed and how hints began reading real progress.
08WIRING PUZZLE DEEP DIVE
Mobile hit areas, single-touch input, and a shutter that responds in the room.
09AUDIO IMPLEMENTATION
Trimming silence, layering room states, and making every action immediate.
10MOBILE UI DEEP DIVE
Rebuilding investigation, inventory, and popups for a portrait screen.
11LOCALIZATION REVIEW
Manually aligning every clue, error, inventory line, and permanent URL.
SUPPORT THE NEXT ROOM
WE KEEP THE
PRODUCTION RECORD OPEN.
ROOM 404 is built by a small team that documents the story, puzzle, visual, and sound work behind each room. Support is optional; the game and its core production archive remain free. Contributions help reserve focused production time for the next episode.
If you open the next door for us,
we will build the world behind it.
YOUR SUPPORT HELPS US
- Build new rooms and puzzles
- Improve images, video, and sound
- Fund localization and servers
- Shorten development time
THE STORY IS NOT OVER
OUR STORY
IS NOT OVER YET.
Until the next invitation arrives, the door to ROOM 404 will remain open.