- The Mermaid Mask steam demo introduces a gripping maritime locked-room murder mystery set in a decaying harbor town.
- Core investigation mechanics require players to scour environments, analyze physical clues, and solve intricate mechanical puzzles.
- The Mortuga submarine serves as the primary setting, featuring hidden compartments, suspicious characters, and a locked control room.
- The locked cauldron at the crime scene holds the key to the supernatural undertones of the victim's death.
- Wishlist the game on Steam to stay updated on the full release and advanced detective chapters.
The Mermaid Mask steam: Demo Walkthrough
The coastal town of Stonetop is shrouded in thick fog, rotting wood, and forgotten secrets. In the demo of The Mermaid Mask steam version, players assume the role of an investigator arriving at the harbor in the dead of night. Alongside your sleeping assistant, Sally, you are tasked with unraveling a baffling locked-room murder that occurred deep within a newly surfaced submarine.
This walkthrough covers the essential progression paths, hidden details, and environmental puzzles you will encounter while exploring the harbor and the mysterious vessel.
Video Highlights:
- Stonetop Inn Investigation: Finding the initial case file and historical lore books at 4:00 AM.
- Harbor Navigation: Tracking the eerie green light past the fountain square to the docked submarine.
- Submarine Exploration: Navigating the pink-lit drawing room and locating the locked serpent cabinet.
- The Illusion Theater: Examining the final crime scene, analyzing the victim, and inspecting the mysterious cauldron.
Your journey begins inside the Stonetop Inn. The atmosphere is immediately hostile and abandoned. While Sally rests on a bench, you must scour the tavern for clues. The wood is rotting, the bar stools are unstable, and a single book titled Hex of the Helmsman by JD Worman sits on the counter. This book details historical fishing trips onboard a ship named the Dearest Selena, hinting at the deep-seated maritime lore of the region.
On the bar counter, you will find the official case file left by Captain Seafoam, the mysterious figure who hired you. The file outlines the bizarre death of Magnus Mortuga, but the captain is nowhere to be found. Suddenly, an eerie green light shines through the windows from the harbor, prompting you to wake Sally and venture out into the cold night.
Do not waste time trying to interact with the rotting bar stools or locked doors inside the inn. Your primary objective is to secure the case file and follow the green light outside before it fades.
Step-by-Step Investigation Guide
Navigating the harbor requires a keen eye for detail. The path to the submarine is littered with remnants of Stonetop's glory days, including the abandoned Mr. Grip Emporium and a decaying billboard advertising a performance by Whan Wolf at the Fortuna Hall theater.
To reach the crime scene and begin your official deduction, follow these precise steps.
Examine the Stonetop Fountain
Locate the large stone statue in the center of the square. It depicts a fisherman wrestling with a creature known as the Silkworm Serpent. Read the inscription to understand the local mythology surrounding sea serpents with legs.
Locate the Mortuga Submarine
Follow the fading green light to the edge of the harbor. You will discover a surfaced submarine. Note the nameplate on the hull: the original name Seafo has been aggressively crossed out and replaced with Mortuga, signaling a past mutiny.
Enter the Submarine Hatch
Climb down the main ladder into the dark interior. The control room door is heavily taped and locked from the inside, with a warning note instructing you to proceed directly to the back of the vessel to locate the crime scene.
Secure the Drawing Room Clues
Before heading to the crime scene, explore the drawing room. Turn on the main light switch to illuminate the pink-hued room. Inspect the puffer fish lamp, the playing cards, the half-finished wine glass, and the locked serpent statue.
The harbor and submarine layouts are tightly packed but filled with environmental storytelling. Use the table below to track the most critical locations and the primary clues associated with them during your walkthrough.
| Location | Key Clues Found | Primary Significance |
|---|---|---|
| Stonetop Inn | Hex of the Helmsman book, Captain's file | Establishes the initial case details and background |
| Fountain Square | Silkworm Serpent statue, old billboard | Hints at local folklore and historical timeline |
| Submarine Deck | Green light source, altered nameplate | Suggests a mutiny and active luring mechanism |
| Drawing Room | Half-finished wine, playing cards, S-tables | Recreates the final moments and social context |
| Illusion Theater | Magnus Mortuga's body, cauldron, stool | The central crime scene containing the murder puzzle |
The green light emanating from the wooden buoy on the deck fades the moment you step aboard. This suggests the submarine was actively broadcasting a signal to draw the investigators to this exact location.
Submarine Puzzles and Clue Solutions
The interior of the Mortuga is designed to disorient and intrigue. As you move past the locked control room, you enter a lavishly decorated drawing room. The room plays unsettling, classical music through wall-mounted speakers, evoking the atmosphere of a masquerade party.
To progress further, you must analyze the environmental anomalies and prepare to solve the mechanical puzzles left behind by the crew.
One of the central puzzles in this area involves a large metal statue of a serpent with a built-in cabinet. This cabinet is secured by a locking mechanism consisting of four rotating dials, each displaying different shapes in a central window. To unlock it, you must cross-reference the shapes with details found in the Hex of the Helmsman book and the physical layout of the drawing room's Z-shaped (or S-shaped) tables.
| Clue Item | Description | Investigation Note |
|---|---|---|
| Wooden Stool | Overturned standard bar stool | Matches the Stonetop Inn stools, suggesting transport |
| Serpent Cabinet | Metal statue with four rotating shape dials | Requires a specific combination to unlock the interior |
| Cauldron | Locked metal vessel at Mortuga's feet | Scratched on the inside, suggesting something was trapped |
| Upside-Down Poster | Taped drawing of the Illusion Theater | Possible misdirection or symbolic clue left by the killer |
| Broken Bottle | Shattered glass on the theater floor | Dropped by Mortuga during the fatal struggle |
The music playing in the drawing room is described by Sally as the kind of music played at a fancy party for masked vampires. Keep this theatrical, masquerade theme in mind when analyzing the motives of the suspects.
Analyzing the Illusion Theater Crime Scene
At the very back of the submarine corridor lies the "Illusion Theater." This tiny space, separated from the corridor by a simple door, is where Magnus Mortuga met his end. The crime scene presents a classic locked-room mystery that challenges your logical deduction skills.
Magnus Mortuga was found lying on his back with a massive cut across his neck. Strangely, there is no murder weapon at the scene—no knife, blade, or sharp tool. The room was bolted securely from the inside, leaving no logical exit route for a human killer.
To piece together what happened, you must weigh the three primary theories supported by the environmental evidence.
The Paranormal Entity
- Locked-Room Mystery: The room was bolted from the inside.
- Internal Scratches: The cauldron shows claw-like marks.
- Unexplained Green Light: Suggests supernatural elements at play.
The Captain's Mutiny
- Altered Nameplate: The submarine was renamed from Seafo to Mortuga.
- Familiar Stool: The crime scene stool matches the local inn's furniture.
- Captain Seafoam: Hiding in the control room, directing investigators away.
The Illusionist's Trick
- Rebranded Theater: The corridor was hastily turned into a stage.
- Upside-Down Poster: Indicates a staged scene or visual misdirection.
- Missing Weapon: A classic magic trick setup where the tool disappears.
The most unsettling element of the room is the heavy iron cauldron resting at the victim's feet. According to the case file, this cauldron had never been unlocked prior to the murder. However, close inspection reveals deep scratch marks on the inside of the lid, suggesting that something—or someone—was trapped inside and desperately trying to claw its way out.
When formulating your final thoughts at the end of the demo, combine the clues: Magnus Mortuga unlocked the cauldron, and he was subsequently killed by whatever was residing inside it.
Steam Release Expectations & Progression
The demo of The Mermaid Mask steam version offers a brilliant vertical slice of the game's atmosphere, writing, and puzzle design. It establishes a dark, maritime noir tone that leaves players eager to explore the full release.
While the demo concludes shortly after you analyze the Illusion Theater and formulate your initial theories, the full Steam release promises to expand significantly on these mechanics.
| Feature | Demo Version | Full Steam Release |
|---|---|---|
| Playable Areas | Stonetop harbor and Mortuga submarine | Expanded coastal town, lighthouse, and deep-sea ruins |
| Puzzles | Serpent dial cabinet, basic room navigation | Multi-layered environmental and narrative puzzles |
| Case Files | Magnus Mortuga murder investigation | Multiple interconnected marine mystery cases |
| Save System | Automated checkpoints only | Full manual saves and chapter select options |
To ensure you have fully completed all content available in the demo, use the checklist below to verify your progress before wishlisting the game on Steam.
Demo Investigation Milestones:
- Locate the Hex of the Helmsman book inside the inn
- Inspect the Silkworm Serpent fountain statue
- Discover the Mortuga submarine in the harbor
- Unlock the drawing room light switch
- Examine all five active clues at the crime scene
If you enjoyed the atmosphere and mechanical puzzles of the demo, head over to the Steam store page to wishlist the game. This directly helps the developers gain visibility ahead of the full launch.
Frequently Asked Questions
Q: How do I access the full game of The Mermaid Mask steam version?
You can download the official demo of The Mermaid Mask directly on Steam. The full game is scheduled for release later, expanding on the Stonetop harbor mystery with multiple interconnected cases.
Q: What is the solution to the serpent cabinet puzzle in the submarine?
The cabinet puzzle requires you to rotate four dials to match specific shapes. These shapes correspond to the environmental clues found on the Z-shaped tables in the drawing room and the maritime illustrations in the case files.
Q: Is Captain Seafoam the killer in The Mermaid Mask?
While Captain Seafoam is highly suspicious—having locked himself in the control room and left a misleading case file—the demo leaves his ultimate role ambiguous to set up the full game's narrative.
Q: What does the locked cauldron at the crime scene represent?
The locked cauldron is the central piece of the locked-room mystery. Scratch marks on the inside indicate that a physical or supernatural entity was sealed within it before Magnus Mortuga unlocked it.
Keep your save files intact, as some progress or narrative choices made during the Steam demo may carry over or unlock exclusive cosmetic rewards in the full release.