Zell23 Games released a new game called Mysterious Abandoned Building and the version is Demo 1.27. The game’s story is about The game takes place inside a decaying, multi-floor abandoned building filled with dark corridors, strange rooms, and hostile creatures. The focus is on slow exploration, environmental tension, and navigating the building’s floors while encountering enemies and scripted events. Each update typically introduces new rooms,
enemy animations, or mechanics, and reflects the author’s iterative development style. Unlike his more combat-focused projects, Nazo no Haibiru leans into a claustrophobic horror tone, highlighting tight spaces, surprise encounters, and survival-style progression. Players must explore carefully, pay attention to environmental clues, and avoid or endure encounters with the building’s residents.
Developer
Zell23
Version
1.80
File Size
179 MB
Censored
No
Language
English
Platforms
Windows
Game Version ChangelogLatest
v1.80
Fantia article IMPORTANT NOTICE REGARDING FUTURE UPDATES This current version is intended to be the final release. Due to the difficulties of publicly sharing adult (H-animation) content while co-developing the project, we have determined it is no longer feasible to continue updating this title.
VERSION 1.80 UPDATE DETAILS New Content
New Enemy: Added a new “Unknown” enemy type: Sahagin.
New Scenes: Added adult (H) animation sequences for the Sahagin.
Location: The Sahagin hunts in damp, waterside areas.
Specific Event: This update includes a capture scene where the character Hop is caught by the Sahagin. Note: In this specific scenario, the player cannot save her.
Game Flow Changes
NEW GAME: Now starts with the full introductory sequence.
Demo Room System To facilitate viewing specific scenes, a central “Demo Room” has been added.
Navigation: Use the gates in the room to warp directly to specific H-event locations.
Emergency Return: If you get stuck or an event breaks:ç
B_ver: Press SPACE to return to the Demo Room.
A_ver: Press A to return to the Demo Room.
Warnings
Speed Toggle: You can still press ‘S’ to increase game speed. However, this may cause character position errors and prevent events from triggering correctly. Please use with caution.
Visual Effects: Some effects, such as cross-section diagrams, are currently experimental and may be changed or removed without notice.
Enemy Roster: The following enemies are available in the demo:
