The Mermaid Mask Achievements Guide: All 21, No Spoilers

This The Mermaid Mask achievements guide confirms all 21 unlocks straight from Steam's own Community stats page, and it's honest about the fact that 15 of them stay completely hidden by design. That's not a research gap on this site's part: SFB Games built a whodunit, and showing the exact trigger for a suspect-specific achievement would hand players the answer before they've earned it. Our The Mermaid Mask walkthrough guide already covers all 8 suspects and the early puzzles without spoiling the final reveal; this guide does the same for achievements specifically.

TL;DR: The Mermaid Mask has 21 total achievements, and only 6 show a public description; the other 15 are hidden, an unusually high ratio for this site's achievement guides. The rarest confirmed unlock rate belongs to Silversnake Sleuth at 27.7% of players. One achievement, Tangle Tower, is a real, confirmed self-reference to developer SFB Games' own earlier mystery game. Clue collection (Gather the Clues and its harder follow-up) is confirmed as a real prerequisite for the rarer achievements further down the list.

How many achievements does The Mermaid Mask have? (quick answer)

21. Steam's public Community stats page for The Mermaid Mask lists all 21 by name and unlock percentage, but only 6 include a visible description. The other 15 show nothing until you earn them, which is Steam's standard way of flagging a spoiler-sensitive unlock, and given this is a mystery game built entirely around a deduction reveal, that ratio makes sense rather than looking like missing data.

Key takeaways

• 21 total achievements, all base game, confirmed directly from Steam's Community stats page.
• Only 6 have a public description. The other 15 are hidden by design, not by an incomplete source.
• The rarest confirmed achievement is Silversnake Sleuth at 27.7% of players.
• Clue collection is a real, tracked prerequisite: Gather the Clues (72.6%) and Gather the Clues, But For Real This Time (70.3%, hidden) both explicitly reference finding all the clues.
• The Tangle Tower achievement is a genuine, confirmed reference to developer SFB Games' own 2019 mystery game, not a fabricated or coincidental name.
• The Mermaid Mask launched July 16, 2026 at $19.99 and sits at Overwhelmingly Positive (2,742 reviews, 99.5% positive) as of this guide's research pass, an exceptionally strong score for a $19.99 indie release.
• Still deciding whether to buy? Our Mermaid Mask review covers that question in full.

The 6 confirmed achievements

These are the only unlock conditions Steam shows publicly. Everything else on the list is spoiler-hidden.

Notice that Gather the Clues, But For Real This Time is hidden despite its name making its general purpose obvious. That's a useful pattern to understand before you go looking for spoilers elsewhere: SFB Games hides an achievement's Steam description independently of whether the name itself is a giveaway. A hidden description doesn't always mean a deep story secret; sometimes it just means the exact completion threshold isn't public.

Break Time, tied to reading the in-game Movie Magazine, is a reminder that this game rewards exploring its world beyond the core suspect interviews. The magazine isn't a clue in the mystery-solving sense, but SFB Games built an achievement around finding it anyway, which tracks with how thoroughly the Mortuga Submarine setting is furnished with readable flavor text throughout, the same kind of environmental detail our Mermaid Mask review singled out as one of the game's strengths.

Steam achievement descriptions are a legitimate primary source for confirming otherwise-undocumented mechanics, the same method this site used for Security 51's tips guide and Denshattack's achievement guide. The difference here is what the source itself confirms: most games' achievement text explains what to do, while The Mermaid Mask's own text often confirms only that something exists.

The Curse in the Cauldron, the game's most common achievement at 94.2%, fires simply for reaching Chapter One. This scene is exactly the kind of early-game atmosphere that achievement is built around.

The 15 hidden achievements, sorted by rarity

Since Steam gives no description for these, this section reports only what's actually confirmed: the name and the unlock rate. No guessed trigger conditions.

Two names are worth a closer, careful look, without crossing into invented mechanics. HER (59.5%) matches a location name visible in this guide's own hero image, a red-lit parlor with a glowing "HER" sign on the ceiling, which suggests the achievement is tied to reaching or interacting with that specific room rather than anything about a character. That's a reasonable inference from a visible in-game location name, not a guess about story content.

Tangle Tower (78.3%) is the more interesting case, and it's fully confirmed, not speculation: SFB Games' own Steam developer page lists Tangle Tower as one of their prior releases, alongside Detective Grimoire, Crow Country, and Haunt the House: Terrortown. Naming an achievement after their own earlier mystery game is a real, verifiable self-reference, the kind of detail a fan of the studio's other work would recognize immediately. What specifically triggers it in The Mermaid Mask isn't public, but that it's a genuine developer callout, rather than a coincidence, is confirmed.

GODEEPER: If you want the full non-spoiler suspect and puzzle breakdown before circling back to these hidden unlocks, our walkthrough guide is the companion piece to read first. The Mermaid Mask Walkthrough Guide: All 8 Suspects →

What the rarity spread actually tells you

The confirmed achievements cluster at the top of the rarity list (94.2% down to 65.5%), and the hidden ones spread across almost the entire range, from 83.1% down to 27.7%. That overlap matters: it means the hidden achievements aren't uniformly "endgame-only" unlocks bunched at the bottom. Several sit above 70%, meaning most players trigger them without deliberately hunting for anything, which fits achievements tied to normal story progression rather than optional side content.

Sally. We've been over this. sits at 30.2%, well below the story-progression cluster above 70%, suggesting it's tied to a specific, repeatable interaction rather than something every player triggers by default.

The real split worth planning around is the bottom three: Secret of the Swamp (36.4%), Sally. We've been over this. (30.2%), and Silversnake Sleuth (27.7%). All three sit meaningfully below everything else on the list, including the two confirmed clue-collection achievements. That gap is the closest thing to a completionist warning this guide can give without inventing what isn't public: expect these three to require something beyond a single clean playthrough, whether that's a specific dialogue path, a repeat interaction, or an alternate solve.

Step-by-Step: a sensible completion order

1. Play through normally, no guide, for your first solve: The Curse in the Cauldron, Break Time, Lever Lover, and The Mermaid Mask itself will all fire from ordinary progress, and going in blind is the actual point of a whodunit.

2. Deliberately sweep every room for clues before accusing a suspect: Gather the Clues (72.6%) confirms basic clue collection matters, and doing this properly on your first run avoids needing an extra pass later just for this achievement.

3. Read the Movie Magazine and explore flavor content: Break Time rewards this specifically, and the Mortuga Submarine has enough readable detail scattered around that a completionist pass benefits from slowing down, not rushing to the next suspect.

4. On a second pass, hunt down every interactive object and character exchange: several of the mid-rarity hidden achievements (77-83%) likely track specific interactions you can miss on a normal playthrough while focused on the central mystery.

5. Save the bottom three for a dedicated completionist session: Secret of the Swamp, Sally. We've been over this., and Silversnake Sleuth all sit well below the rest of the list, so budget extra time and expect to need more than one clean solve.

Frequently Asked Questions

How many achievements does The Mermaid Mask have? 21 total, confirmed directly from the game's public Steam Community stats page. Only 6 show a visible unlock description; the other 15 stay blank until you earn them, an unusually high hidden ratio compared to most achievement lists on this site.

Why are so many achievements hidden in The Mermaid Mask? The game is a whodunit built entirely around deduction and reveals. SFB Games hiding 15 of 21 achievement descriptions matches the genre: showing the trigger for a suspect-specific or ending-specific unlock would spoil the exact thing the game asks you to figure out.

What is the rarest achievement in The Mermaid Mask? Silversnake Sleuth, at 27.7% of players, the lowest unlock rate on the list. It's hidden, so Steam doesn't confirm what triggers it, but its position at the very bottom of the rarity list suggests it's tied to a harder, less-obvious ending or deduction path.

Do you need to find all the clues for 100% completion? Yes, at minimum. Gather the Clues (72.6% of players) and its harder follow-up, Gather the Clues, But For Real This Time (70.3%, hidden), both explicitly track clue collection, confirming a full clue sweep is required before you can chase the rarer, story-locked achievements.

Is The Mermaid Mask connected to Tangle Tower? Not narratively, but the achievement named Tangle Tower is a real, confirmed reference to SFB Games' own earlier mystery game of the same name. SFB Games' Steam developer page lists Tangle Tower, Detective Grimoire, and Crow Country alongside The Mermaid Mask.

Can you get all achievements in one playthrough of The Mermaid Mask? That's not confirmed either way, since 15 of the achievement conditions aren't public. Given the game centers on interviewing 8 suspects and reaching one deduction, a completionist run likely means replaying to see outcomes a single correct solve wouldn't show you.

Related Reading

• The Mermaid Mask Walkthrough Guide: All 8 Suspects: the full non-spoiler suspect and puzzle breakdown this guide is designed to complement.
• Gamble With Your Friends Achievements Guide: another Steam-sourced achievement breakdown, for a completely different genre.
• Security 51 Tips Guide: another indie where the achievement list itself doubled as the primary source for undocumented mechanics.
• Winter Burrow Achievements Guide: a cozier game with the same discipline of not inventing what a source doesn't confirm.
• Black Jacket Achievements Guide: a card-focused roguelite's take on hidden, spoiler-sensitive unlocks.

References

• The Mermaid Mask on Steam: official store page, price, and review data.
• The Mermaid Mask Steam Community Achievements: the primary source for every achievement name, description, and unlock rate in this guide.