THE UNDERREALM FIELD GUIDE

Shroom and Gloom Pathways

Two ways toward The Gloom. Know what changes when you take another path.

Game version: Early Access / Guide updated: September 11, 2026

Early Access launched with two pathways toward The Gloom. The newly available route is The Mysterious Facility, with a separate card pool, enemies and rewards.

An illustrated cave corridor from official game media
THE EXISTING ROUTE

The original path

The original route and The Facility have different card pools. Do not assume a card you relied on in one will appear in the other.

Exploring a dungeon between fights.

NEW IN EARLY ACCESS

The Mysterious Facility

The Facility has its own cards, enemies and rewards. Quests unlock access.

A step-by-step Facility unlock walkthrough is not included here yet.

What does choosing a pathway change?

Changing paths changes the cards, enemies and rewards you encounter. Rebuild your plan around what you find rather than chasing the same cards every run.

Which path should I choose?

Start with a route you can already enter while learning the basic loop. When you try another path, pay attention to its tools and card pool before committing to a familiar combo.

How do I unlock The Facility?

Complete quests to open access to The Facility. The exact quest requirements are not covered in this guide yet.

How do characters fit in?

Your starting decks and base Foresight affect which cards work well together. Compare those tools before committing to a plan for a new route. Choosing a character →

Prepare your Explore Deck for The Facility

Revealing a structure does not necessarily make it usable. A vending machine may still need fixing before you can claim its reward. Keep tools for both jobs.

  • Bring the right tools. Keep track of which current cards can reveal, fix, unlock or break. Several copies of one action will not solve every obstacle.
  • Support the structures you choose. A structure’s reward matters less if the deck cannot provide its required interaction. Keep a fixing tool available if the structures you want require one.
  • Inspect the merchant’s currency. If a merchant asks for Data, save enough for the trade. Do not spend an activation resource as though it were interchangeable with food.
  • Budget for the next encounter. Optional searches and repairs can become costly if they require repeated rests. Check the room warning before chasing another reward.

For the combat side of this route, read Gunk, Data & Machines.

Sources & version notes

Last verified against the sources below: . This is a source check, not an in-game test of every interaction. Unconfirmed details are labelled separately.

Gameplay transcript sources

Original summaries based on editor-supplied YouTube transcripts. Video URLs, recording dates and build IDs were not included; footage has not been independently checked. Titles and timestamps identify the supplied excerpts.

  • I CLEANED The FACILITY with GUNK & MACHINES in this Double Deckbuilder! - Shroom and Gloom — 02:26–05:14; 18:09–20:15; 25:31; 38:12–39:37.