Compare Project Blue Book: Hidden Mysteries prices across trusted key stores and find the best deal. Developed by Three Gates. Published by Legacy Games. Released on 3/15/2021. Available on PC. Genres: Adventure, Casual, Indie.

Cold War paranoia meets hidden-object comfort gaming: three UFO cases ripped from real declassified files, wrapped in a 1950s atmosphere that rewards patience over reflexes.

My honest reaction when I first loaded this up was quiet surprise at how much effort the period dressing gets. The Cold War palette is muted and purposeful - grey government corridors, dusty airfields, the kind of institutional beige that makes a glowing saucer sighting feel genuinely uncanny by contrast. Three Gates, a small Swedish studio based on the island of Gotland, clearly cared about the license they were working with, and that care shows in the scene construction even if the overall package is modest. Mechanically, this is a straightforward hidden-object adventure with three full cases to work through, each built around real declassified UFO investigations that the actual U.S. Air Force Project Blue Book program examined between 1952 and 1969. Each case layers hidden-object scenes with dialogue sequences and embedded minigames and puzzles, so the pacing doesn't collapse into pure object-hunting. The story was written by science-fiction author Steven-Elliot Altman, and his hand is visible in the connective tissue between scenes - there's a genuine attempt to make you feel like a field agent piecing together a case file rather than just clicking through a checklist. Dr. J. Allen Hynek and Captain Quinn, voiced likenesses drawn from the HISTORY Channel TV series, appear throughout as guides. Fans of that show will get more out of the character work; for everyone else, they function as competent narrative anchors. Where the game underdelivers is scope. Three cases is a thin offering, and the overall runtime sits comfortably in the casual tier - you're looking at a few hours before credits roll, even if you chase the per-level star ratings or hunt for that elusive 100% completion the Steam community has puzzled over. The puzzle and minigame variety is serviceable rather than inventive, and genre veterans who have played through Big Fish-style productions will recognize the rhythms immediately. There is no meaningful difficulty curve; the challenge is observational, not strategic. That's a deliberate design choice and the right audience will find it relaxing, but it does mean the experience is front-loaded with its best impressions. Who is this for? Hidden-object players who want a themed change of pace from gothic mansions and fairy-tale villages will find the Cold War UFO setting genuinely refreshing. The historical grounding gives the hunt-and-click loop a hook that similar games often lack. It's also a clean pick for anyone who watched the TV series and wants a few more hours in that world without committing to something demanding. Come in without expecting a sprawling investigation sim and the handcraft in the scene art and the quietly atmospheric score will do their quiet work on you. Kai, Scout Team

Project Blue Book: Hidden Mysteries

Project Blue Book: Hidden Mysteries

Mar 15, 2021Three GatesLegacy Games
GamerScout Says

Cold War paranoia meets hidden-object comfort gaming: three UFO cases ripped from real declassified files, wrapped in a 1950s atmosphere that rewards patience over reflexes.

PC
Best Price Available
€3.49
at Eneba
Lowest tracked: €3.23
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GamerScout Verdict

Best for hidden-object regulars who want a change of scenery and can live with a short, unhurried case file.

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€3.49
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StandardGlobalSteam KeyKey
€3.49-39%
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StandardGlobalSteam KeyKey
€3.49
Priced in EUR by the store
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StandardGlobalSteam KeyKey
€3.91
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StandardGlobalSteam KeyKey
€4.56-20%
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StandardEurope (EU)Steam KeyKey
€5.69
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Price History

Lowest tracked
€3.2317 Aug 2026
Current best
€3.49
Keyshops
€3.20€3.31€3.41€3.525 Jun28 Jun20 Jul12 Aug3 Sept
5 Jun — 3 Sept
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Screenshots & Media

About Project Blue Book: Hidden Mysteries

My honest reaction when I first loaded this up was quiet surprise at how much effort the period dressing gets. The Cold War palette is muted and purposeful - grey government corridors, dusty airfields, the kind of institutional beige that makes a glowing saucer sighting feel genuinely uncanny by contrast. Three Gates, a small Swedish studio based on the island of Gotland, clearly cared about the license they were working with, and that care shows in the scene construction even if the overall package is modest. Mechanically, this is a straightforward hidden-object adventure with three full cases to work through, each built around real declassified UFO investigations that the actual U.S. Air Force Project Blue Book program examined between 1952 and 1969. Each case layers hidden-object scenes with dialogue sequences and embedded minigames and puzzles, so the pacing doesn't collapse into pure object-hunting. The story was written by science-fiction author Steven-Elliot Altman, and his hand is visible in the connective tissue between scenes - there's a genuine attempt to make you feel like a field agent piecing together a case file rather than just clicking through a checklist. Dr. J. Allen Hynek and Captain Quinn, voiced likenesses drawn from the HISTORY Channel TV series, appear throughout as guides. Fans of that show will get more out of the character work; for everyone else, they function as competent narrative anchors. Where the game underdelivers is scope. Three cases is a thin offering, and the overall runtime sits comfortably in the casual tier - you're looking at a few hours before credits roll, even if you chase the per-level star ratings or hunt for that elusive 100% completion the Steam community has puzzled over. The puzzle and minigame variety is serviceable rather than inventive, and genre veterans who have played through Big Fish-style productions will recognize the rhythms immediately. There is no meaningful difficulty curve; the challenge is observational, not strategic. That's a deliberate design choice and the right audience will find it relaxing, but it does mean the experience is front-loaded with its best impressions. Who is this for? Hidden-object players who want a themed change of pace from gothic mansions and fairy-tale villages will find the Cold War UFO setting genuinely refreshing. The historical grounding gives the hunt-and-click loop a hook that similar games often lack. It's also a clean pick for anyone who watched the TV series and wants a few more hours in that world without committing to something demanding. Come in without expecting a sprawling investigation sim and the handcraft in the scene art and the quietly atmospheric score will do their quiet work on you.

Kai
Kai · Scout Team

Indie & narrative

Tags

singleplayerachievementstier:sub-5Hidden ObjectCold War SettingLicensed IPTV Tie-InDeclassified CasesStar Rating SystemShort Completion TimeMinigame VarietyPeriod Atmosphere

System Requirements

Minimum

OS
Windows 7 (64-bit version)
Memory
2 GB RAM
DirectX
Version 9.0
Graphics
512 MB
Processor
1.5 Ghz

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Game Info

Developer
Three Gates
Publisher
Legacy Games
Release Date
Mar 15, 2021

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Frequently asked questions about Project Blue Book: Hidden Mysteries

How much does Project Blue Book: Hidden Mysteries cost?

As of 3 September 2026, the cheapest in-stock offer for Project Blue Book: Hidden Mysteries is €3.49 at Eneba, out of 6 live offers we track across verified key stores. Prices change daily — the table on this page is refreshed continuously.

Where can I buy Project Blue Book: Hidden Mysteries cheapest?

The lowest in-stock price we track for Project Blue Book: Hidden Mysteries is €3.49 at Eneba (3 September 2026). We compare 6 live offers from verified key stores — the full table with every store and its trust score is on this page.

What platforms is Project Blue Book: Hidden Mysteries available on?

Project Blue Book: Hidden Mysteries is available on PC.

When was Project Blue Book: Hidden Mysteries released?

Project Blue Book: Hidden Mysteries was released on 15 March 2021.

Who developed Project Blue Book: Hidden Mysteries?

Project Blue Book: Hidden Mysteries was developed by Three Gates and published by Legacy Games.