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Umbral

A brutal snowstorm. An abandoned research station. And something ancient beneath the ice.

Located on a Norwegian archipelago at the edge of the world, King’s Bay Research Station was built for long-term isolation. Now it sits half-buried in snow, lights flickering behind frosted glass, corridors choked with debris, and the unmistakable signs of something gone very wrong.

Your chopper went down in the whiteout before you ever saw the station. Through the blizzard, its steel bones loom ahead—cold, quiet, and waiting.

Umbral is an atmospheric horror–exploration map for Garry’s Mod with a loose objective structure and multiple endings. Follow the hints—or wander off the path and find your own fate.

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• Full Navmesh & AI Nodegraph (NPC/NextBot ready)
  
  
• HDR & SDR lighting with built cubemaps
  
  
• Detailed soundscapes and spatial ambience
  
  
• Large set of custom assets (models, materials, sounds, particles)
  
  
• 6 different endings to discover
  
  
• Achievement system with 13 achievements (with in-world trophies)
  
  
• Two modes: an immersive Story mode and a build-friendly Sandbox mode, which can be toggled between at will

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Umbral is a large, performance intensive map with a lot of effects and assets. Although every effort has been made to optimize the map, users of lower-end systems may need to reduce settings for the smoothest experience.

Explore the station with the aim of opening new routes and ultimately escaping. Progress comes from restoring power, unlocking doors, and spotting opportunities to move deeper. If you’re unsure, watch for highlighted/interactable objects—they usually mark the next useful action. A full Walkthrough / Guide (routes, endings, puzzle tips) can be found here:

https://steamcommunity.com/sharedfiles/filedetails/?id=3556518353

By default, players are placed into Story mode. Story mode removes the player loadout, disables the spawn menu, and tweaks movement settings for an enhanced immersive experience.

Should you wish to switch to Sandbox mode, you may do so at any time with the chat or console commands below. See Console / Chat Commands.

Umbral features a custom achievement system for players who want to experience everything the map has to offer.

There are currently 13 achievements in total, each with an in-game trophy. A full achievement list and unlock steps are in the Walkthrough / Guide.

Note: Achievement saves are server-side. On remote servers, clients won’t unlock achievements locally; the server’s save is authoritative.

Although there is technically nothing preventing you from playing Umbral with friends, you should bear in mind that it was very much designed as a single player experience.

It's unlikely you'll encounter anything game-breaking, or that will prevent you from completing the map, but you may run into some strange issues, particularly if players are exploring different areas at the same time.

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!togglesandbox – Switch between Story and Sandbox modes.


*See the map guide for a full list of achievement IDs

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gm_umbral began life as nmo_blizzard—an objective map for the mod No More Room In Hell (NMRIH). It was developed over six months starting in late 2024 and released in April 2025 as a collaboration between Hax and me.

Work on the Garry’s Mod port began in May 2025. Rather than a straight copy, Umbral is a near-complete rework: systems rebuilt, spaces re-imagined, and a new focus on atmosphere, exploration, and multiple endings. Thanks for playing.


Q: The map never loads / gets stuck at Loading Lua
A: I am collecting information about this problem, so if you are experiencing this issue please drop a post in the related discussion. I suspect this is most likely a result of running too many addons or an incompatibility with other addons on the workshop.

Q: Some textures and models are missing in the underground section
A: Some users have reported missing Episode 2 content in the underground sections of the map. Try remounting or mounting & then unmounting Half Life 2 & it's episodes and then restarting Garry's mod. No additional content should be required for this map.

Q: The game crashes as soon as the map loads
A: I am collecting information about this problem. I suspect this is due to incompatibilities with other addons.

First, please ensure that you are playing on the 64 bit chromium branch of Garry's mod.
Failing that, try disabling any addons likely to come with a significant additional processing cost or memory requirement, any addon that automatically spawns additional entities, or any addon that is intended to improve FPS.

If you are still experiencing crashes, please post in the related discussion so I can work on identifying the issue.


Hax — collaborator on the original map; continued support, additional models, and exhaustive playtesting of the port.

Jacob Robbins — for the excellent Source skybox collection, one of which features in this map, and for authoring some useful tools / scripts that helped me to prepare for publishing.

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If you enjoyed Umbral…

Please consider liking, favouriting, and sharing with others.

Bugs or feedback? Please leave a comment below.

Curious about the original? Try nmo_blizzard (NMRIH)

Our other NMRIH maps:
Hax — nmo_ghostport
Bine — nmo_extra