Project Blue Book: Hidden Mysteries
Developed by Three Gates · Published by Legacy Games
At a glance
Overview
An adventure, casual, indie game by Three Gates, published by Legacy Games — single-player.
Steam’s own one-line description: “It’s 1952, and the U.S. Air Force is operating a top-secret investigation: Project Blue Book. As a newly recruited agent, it’s your job to uncover the truth behind these real declassified UFO sightings. Test your observation and investigation skills in this out-of-this-world hidden object adventure!” — developer/publisher text via the Steam store page.
Reception & community
Review sentiment, ownership and peak-concurrent estimates via SteamSpy; tags are player-voted on Steam. Estimates change over time.
Features & modes
Derived from the gameplay modes and feature categories Steam lists for Project Blue Book: Hidden Mysteries.
| Feature | Supported |
|---|---|
| Single-player | Yes |
| Multiplayer | No |
| Co-op | No |
| Online co-op | No |
| PvP | No |
| Cross-platform multiplayer | No |
| Full controller support | No |
| Partial controller support | No |
| Steam Cloud saves | No |
| Steam Achievements | Yes |
System requirements (PC)
As published on the Steam store page. Requirements can change between updates.
Minimum
- OS *: Windows 7 (64-bit version)
- Processor: 1.5 Ghz
- Memory: 2 GB RAM
- Graphics: 512 MB
- DirectX: Version 9.0
- Additional Notes: Storage 1.5 GB
Supported languages (1)
Project Blue Book: Hidden Mysteries FAQ
Answered from the official Steam listing as of June 2026. Where something hasn't been announced, we say so rather than guess.
What kind of game is Project Blue Book: Hidden Mysteries?
Steam classifies Project Blue Book: Hidden Mysteries as a Adventure, Casual, Indie game, developed by Three Gates. It’s 1952, and the U.S. Air Force is operating a top-secret investigation: Project Blue Book. As a newly recruited agent, it’s your job to uncover the truth behind these real declassified UFO sightings. Test your observation and investigation skills in this out-of-this-world hidden object adventure!
How much does Project Blue Book: Hidden Mysteries cost?
As of June 2026, Steam lists Project Blue Book: Hidden Mysteries at $6.99. Prices and regional pricing change — check the Steam page for the current figure.
Is Project Blue Book: Hidden Mysteries single-player or multiplayer?
Steam lists these modes for Project Blue Book: Hidden Mysteries: Single-player. It lists a single-player mode.
Is Project Blue Book: Hidden Mysteries on PlayStation, Xbox, or Switch?
Our data comes from the Steam (PC) store, which lists Project Blue Book: Hidden Mysteries for Windows. Console availability isn’t in our Steam-sourced data — check the official site or the console store.
Is Project Blue Book: Hidden Mysteries out yet?
Yes — Steam lists a release date of Mar 15, 2021.
What platforms is Project Blue Book: Hidden Mysteries on?
Project Blue Book: Hidden Mysteries is listed for Windows on the Steam (PC) store. Console availability isn't covered by Steam's PC store data — check the official channels.
Is Project Blue Book: Hidden Mysteries single-player or multiplayer?
Steam lists these modes: Single-player.
How much does Project Blue Book: Hidden Mysteries cost?
Steam lists it at $6.99.
Does Project Blue Book: Hidden Mysteries have achievements?
Yes — Steam lists 10 achievements for Project Blue Book: Hidden Mysteries.
Who made Project Blue Book: Hidden Mysteries?
Project Blue Book: Hidden Mysteries is developed by Three Gates and published by Legacy Games.
Where to get Project Blue Book: Hidden Mysteries
We don't sell games or track prices — this links to the official Steam store page.
View on Steam →Listing details from Valve's public Steam store data · official site. Not affiliated with Valve/Steam, Legacy Games.