Gloomwood: Hidden Mechanics – Sound Propagation, AI Memory & Light Physics Explained

Sound Propagation System — The Most Complex Stealth Mechanic

Gloomwood has one of the most sophisticated sound propagation systems in any stealth game ever made. It's not just a simple radius check — the game tracks multiple variables to determine exactly how sound travels. Understanding this system is the difference between a good player and a great one.

Surface Types and Footstep Noise

The game tracks what surface you're standing on in real-time and adjusts your footstep volume accordingly. Here's the full breakdown:

• Carpet: Silent. You can sprint on carpet without making a sound. This is the only surface where sprinting is safe.
• Wood floors: Loud. Walking on wood makes a moderate sound. Running makes a very loud sound that can be heard through walls.
• Stone: Moderate. Stone muffles footsteps somewhat, but running is still audible.
• Gravel: Very loud. Even walking on gravel makes noise. Crouch-walk on gravel to minimize it.
• Metal: Extremely loud. Metal grates and catwalks amplify every step. Avoid them if possible.
• Water: Loud splashing. Wading through water is as loud as running on wood.

The key insight: you can use surface types to your advantage. If you need to move quickly, find a carpeted path. If you need to be silent, avoid gravel and metal at all costs.

Door Physics and Sound

This is one of the most impressive details in the game. The speed at which you open a door affects how much noise it makes. If you slowly push a door open (by moving your mouse slowly or pressing the interact key gently), it makes almost no sound. If you fling it open, it creaks loudly.

The game measures your input speed — both mouse movement and keyboard input. A slow, deliberate input results in a quiet door. A fast input results in a loud door. This applies to drawers, cabinets, and windows too. Every interactive object with a hinge has this system.

There's also a difference between pushing a door open and pulling it. Pushing is quieter because the door swings away from you. Pulling creates more friction on the hinges. Always push doors when possible.

Sound Occlusion and Propagation

Sound in Gloomwood travels through open spaces but is blocked by obstacles. The game uses a raycasting system to determine if there's a clear path between you and an enemy. If there's a wall in the way, the sound is muffled or blocked entirely.

• Open door: Sound passes through freely. An enemy on the other side of an open door can hear you as if you're in the same room.
• Closed door: Sound is muffled by about 50%. Enemies can still hear loud sounds (gunshots, breaking objects) through closed doors.
• Thin wall: Sound passes through thin walls (wood, plaster) at reduced volume. Enemies in adjacent rooms can hear you if you're loud.
• Thick wall: Stone walls block sound almost entirely. You can be as loud as you want in a stone room and enemies won't hear you.

Sound Distance Falloff

Each sound in the game has a specific range. Here are the exact ranges I've measured:

• Whisper (crouch-walking on carpet): 3 meters
• Footstep (walking on wood): 8 meters
• Footstep (running on wood): 15 meters
• Door creak (slow open): 5 meters
• Door creak (fast open): 12 meters
• Thrown bottle breaking: 20 meters
• Gunshot: 50 meters (alerts the entire map)
• Flash bomb: 30 meters

Use these ranges to plan your movements. If you know an enemy is 10 meters away, you can walk on wood without being heard — but you can't run.

AI Memory System — Enemies Remember You

Gloomwood's enemies have a sophisticated memory system that goes far beyond simple "alert" and "calm" states. Understanding this system is crucial for challenge runs.

Three States of Awareness

Every enemy in Gloomwood exists in one of three states:

• Calm: Default state. The enemy follows its patrol route. It responds to sounds and visual stimuli but isn't actively searching.
• Suspicious: The enemy heard or saw something unusual. It investigates the source. During this state, the enemy is more alert — it checks corners and listens more carefully. This state lasts about 30 seconds.
• Alert: The enemy fully detected you. It chases you and alerts nearby enemies. This state lasts until the enemy loses sight of you for 60 seconds.

Short-Term Memory

If an enemy sees you briefly (less than 2 seconds), they'll search your last known position for 30 seconds. During this time, they're in the Suspicious state. If they don't find you, they return to their patrol route. But here's the important part: they remember where they saw you. On their next patrol pass, they'll pause at that spot and look around.

Long-Term Memory

If an enemy sees you clearly (full detection), they remember your face. The next time they see you, they'll go straight to Alert state without passing through Suspicious. This memory persists for the entire play session. Even if you leave the area and come back, they'll remember you.

The only way to reset long-term memory is to die or reload a save. This is why Ghost runs are so punishing — if you get fully detected once, that enemy will be permanently on edge.

Alert Propagation

When one enemy spots you, they alert nearby enemies. This creates a chain reaction that can lock down an entire area. The propagation range is about 20 meters. If you're in the Streets and one guard spots you, every guard within 20 meters becomes Alert.

But here's a hidden detail: the propagation isn't instant. It takes about 3 seconds for the alert to spread. If you can break line of sight and hide within those 3 seconds, the propagation might not reach all enemies. Some enemies will remain in Calm state because they never received the alert.

Forgotten But Not Gone

After an enemy returns to their patrol route following a search, they remain on "high alert" for 2 minutes. During this time, they're harder to distract — thrown objects have a reduced effect, and they respond to sounds faster. After 2 minutes, they return to normal Calm state.

Light Physics — More Than Just Shadows

The light system in Gloomwood is more complex than "stand in shadows = invisible." Here's the full picture of how visibility actually works.

Dynamic Shadow Casting

Your character casts a dynamic shadow in real-time. This means your shadow can give you away even if you're standing in darkness. If you're hiding in a dark corner but your shadow extends into a lit area, an enemy can see your shadow and investigate.

The fix: stay close to walls. When you're next to a wall, your shadow blends with the wall's shadow and becomes nearly invisible. This is called "shadow blending" and it's one of the most important techniques for Ghost runs.

Enemy Vision Adaptation

Enemies' eyes adapt to light levels. When an enemy moves from a bright area to a dark area, their vision is temporarily reduced. They can't see as well in the dark for about 5 seconds while their eyes adjust. This gives you a window to move through lit areas that would normally be too dangerous.

You can exploit this by luring enemies from bright areas into dark areas, then moving while they're adjusting. The Church's main hall is a great place to practice this — the contrast between the bright altar and the dark pews creates perfect adaptation opportunities.

Light Flicker Timing

Flickering light sources create brief moments of complete darkness. Each flicker follows a pattern — the light goes out for about 0.5 seconds every 3-4 seconds. If you time your movements to these flickers, you can cross lit areas without being seen.

The Theatre has the best example of this. The chandelier in the main hall flickers on a predictable cycle. Time your chandelier jump to the flicker and you'll be invisible during the swing.

Equipment Light

Your lantern makes you visible from much further away. With the lantern off, your visibility range is about 5 meters in darkness. With the lantern on, it's 20 meters. Only use the lantern when you absolutely need to see something, and turn it off immediately after.

There's also a hidden mechanic: the lantern's light flickers when you're near enemies. If you see your lantern flickering, it means an enemy is within 10 meters. Use this as an early warning system.

Shadow Blending — The Ultimate Technique

The most powerful hidden mechanic in Gloomwood is shadow blending. If you stand still in a shadow for 3 seconds, your character's visibility drops to near zero. Even enemies looking directly at you might not see you. The game applies a "stillness bonus" that makes you blend into the background.

This works best in deep shadows (areas with 0% light). In partial shadows (areas with 30-50% light), the bonus is reduced. In full light, it doesn't work at all. The stillness bonus also resets if you move — even a single step breaks it.