The Mermaid Mask Review: SFB's Locked-Room Mystery

The Mermaid Mask review begins in a locked room aboard a submarine. Captain Magnus Mortuga is dead. An ancient stone cauldron sits beside him. The door was locked from the inside. Detective Grimoire and Sally are standing in the corridor trying to figure out how any of this is possible, and the game gives you a 3D cauldron you can rotate, inspect from every angle, and hunt for hidden details on.

That's SFB Games' signature move, and seven years after Tangle Tower established it, the feel of physically picking up a clue object and turning it over in virtual hands still works.

TL;DR: The Mermaid Mask is the fourth Detective Grimoire game, launching July 16 on PC, PS5, Switch, and Switch 2. It's a handcrafted point-and-click locked-room mystery set aboard the Mortuga Submarine, featuring 3D clue examination, a full voice cast, and a Budapest Art Orchestra score. If Tangle Tower was your benchmark for how good this genre could feel, The Mermaid Mask meets it.

The Mermaid Mask review: what you're investigating (quick answer)

A locked-room murder aboard a submarine crewed by eccentric suspects, in an abandoned fishing town off a coast that doesn't fully exist in the real world. Detective Grimoire and Sally Spears are back, investigating the death of Captain Mortuga, a man described variously as an immortal time-traveller, a vampire, and a fraud. The game commits to none of these explanations immediately and lets the contradictions stack up before sorting them.

The mechanical core is the same as Tangle Tower: you gather clues, interrogate suspects, and connect evidence through a case-building screen that rewards lateral thinking over brute-force item combination. The 3D clue objects are new to the series rather than legacy features. In Tangle Tower you examined flat hotspots. Here, every significant piece of evidence is a rendered 3D object you can rotate freely, revealing details that hide on the underside or require a specific angle to read. It's a small difference that makes the investigation feel tactile in a way the predecessor didn't quite manage.

Key takeaways

• Handcrafted point-and-click mystery by SFB Games, launching July 16, 2026
• 3D clue examination replaces the flat hotspot model from Tangle Tower
• Set aboard the Mortuga Submarine off Silkwirm-on-Sea; full voice cast in English
• Budapest Art Orchestra recorded the original score
• Available on PC, PS5, Nintendo Switch, and Nintendo Switch 2
• SFB has confirmed they're taking a break from Detective Grimoire after this title
• Demo available free on Steam covering the opening section

Gameplay

The Mortuga Submarine is not a realistic environment. Its crew includes someone who claims to speak only to the dead, a cook whose kitchen defies submarine geometry, and a navigation officer whose charts describe routes that don't map to any ocean. SFB uses this unreality deliberately: the weirdness of each suspect gives you information about who they are, and the contradictions in their stories become puzzle elements rather than character flavour.

Interrogations follow a branching structure. You present evidence to get new statements, which unlock new evidence, which loop back to the interrogations. The case-building screen in the middle tracks which threads you've confirmed and which remain open. It's a familiar loop if you've played Tangle Tower. The satisfaction of a correct connection clicking into place doesn't degrade on repetition, which is not something you can say about every mystery game that tries this structure.

A typical investigation scene aboard the Mortuga Submarine. The room layout gives you several interactable points before you're ready to question the suspect in the corner.

The 3D examination system is The Mermaid Mask's clearest upgrade over its predecessors. In Tangle Tower, a key clue might be a drawing on a piece of paper that you could zoom into. Here, the equivalent clue is a physical object: you pick it up, tilt it, find the inscription on the base, and carry that detail back to a conversation where it finally becomes useful. The translation to PS5 and Switch via controller is adequate; the triggers rotate the object, though the mouse feel on PC remains the more precise option.

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The Budapest Art Orchestra score is the thing I keep coming back to. Tangle Tower had a good soundtrack. This one is different: recorded live, tuned to individual scenes, shifting based on what you've just discovered. The opening undersea sequence alone made me pause. That's expensive for a game at this scale, and it shows.

What SFB Games does differently

The Mermaid Mask review's clearest case for the game is its puzzle fairness, and that's harder to achieve than it looks. Most point-and-click mysteries solve for atmosphere at the cost of it. The rooms look great, the dialogue is flavourful, and then the solution involves combining a fish with a battery for reasons the game hasn't earned. SFB doesn't do this. The Mermaid Mask's puzzles are constructed so that every solution follows from something you've already found. The "ah, of course" moment is the consistent payoff rather than the exception.

The suspect characterisation is the other differentiator. Each crew member on the Mortuga Submarine is strange in a way that's specific to them, not generic "comic relief" or "red herring" strange. The strangeness is often the point: what a character refuses to explain is exactly what you need to understand. The detective work involves reading people as much as examining objects, and the game is confident enough in its cast to lean into that.

SFB has said publicly that they're taking a break from Detective Grimoire after this. Whether that reads as a finale or a pause, it puts some weight on The Mermaid Mask that most point-and-clicks don't carry. The game seems aware of it. There's a completeness to the way it's built that feels intentional, like SFB wanted to leave the series somewhere specific.

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The 3D clue system in practice: the cauldron from the locked room can be rotated freely. The inscription on the base only becomes readable at a specific angle.

The Mermaid Mask review: verdict

This is SFB Games at their most confident. The locked-room premise gives them a tighter premise than Tangle Tower's sprawling mansion, and they use the constraint well: every room on the submarine is doing narrative work, every character has a specific function in the puzzle architecture. The 3D clue system is the mechanical upgrade that actually changes how the investigation feels. The Budapest Art Orchestra score is the production value that makes you aware something unusual is happening.

If you played Tangle Tower and found the ending anticlimactic (a common complaint), know that SFB has had seven years to think about endings since then. The Mermaid Mask's conclusion is earned. If you want a different genre of indie game with the same commitment to tension: Black Jacket scratches a related itch through blackjack rather than deduction.

Rating: 8.3/10

References

• The Mermaid Mask on Steam: official store page with demo download
• The Mermaid Mask launches July 16 for PS5, Switch 2, Switch, and PC: Gematsu coverage of the release date announcement, June 2026
• The Mermaid Mask release date trailer (YouTube): official trailer from SFB Games confirming July 16 release
• SFB Games is "definitely taking a break from Detective Grimoire" after The Mermaid Mask: Gamereactor interview with SFB Games on the series' future

Frequently Asked Questions

Is The Mermaid Mask related to Tangle Tower? Yes. Both are Detective Grimoire games by SFB Games. Tangle Tower (2019) was the third game in the series. The Mermaid Mask is the fourth. You don't need to play Tangle Tower first. Each case is self-contained, and returning players will recognise Grimoire and Sally.

How long is The Mermaid Mask? The Mermaid Mask runs approximately 4-6 hours for most players, consistent with Tangle Tower's length. Point-and-click mysteries in this style rarely extend past 8 hours, and SFB's pacing keeps things tight.

Is The Mermaid Mask on console? Yes: PlayStation 5, Nintendo Switch, and Nintendo Switch 2, alongside PC on Steam. All versions launched simultaneously on July 16, 2026.

Who made The Mermaid Mask? SFB Games, the UK studio behind Tangle Tower (2019) and Crow Country (2024). The Mermaid Mask is their fourth Detective Grimoire game and their second consecutive multi-platform release.

Is there a demo for The Mermaid Mask? Yes, a free demo is available on Steam covering the opening section of the game. It's a good test of whether SFB's puzzle style clicks for you before committing to the full release.