THE UNDERREALM FIELD GUIDE

Shroom and Gloom Boss Guide

Prepare your deck. Check the encounter rules. Use strategies that match your version.

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

Before a difficult encounter

Before entering a difficult fight, make sure your deck can survive a turn when the combo does not come together.

  1. Inspect the cards you are relying on. Check current costs, targets and trigger conditions.
  2. Review your recovery options. Read what your food and related cards actually restore or produce.
  3. Check whether your damage depends on setup. Have a fallback if a conditional combination is not available.
  4. Read the encounter’s displayed rules. Do not assume that an old video uses the same balance or mechanics.

What about Demo bosses?

A Demo strategy may fail if an enemy’s attacks or phases have changed. Read the encounter’s current rules before repeating an old sequence.

Need help right now?

Consult the Steam discussions with your game version and the encounter’s exact name. Include the boss’s name and what is killing you so other players can help.

For help with card effects and deck choices, see Mechanics and the deckbuilding checklist.

When a dangerous fight changes your plan

Recheck your plan when an enemy changes your card costs or blocks an effect. A turn that looked safe at the start can change after a single play.

  1. Read protection before committing damage. If the current tooltip says an effect will be ignored, consider whether a low-value play can remove that protection. Check the actual rule rather than assuming every shield works this way.
  2. Recount energy after cost changes. A sequence that was affordable at the start of the turn may stop working after the first card.
  3. Plan recovery before spending it. Compare food or a healing finisher with expected incoming damage. Preserve a useful heal when health is already high, unless another trigger makes using it now worthwhile.
  4. Check the next state. A transformation or newly appearing enemy may change your priorities. A large hit does not establish that the encounter is finished.

When an enemy transforms or a new threat appears, pause and read its next action before spending your remaining cards.

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’ve Been Waiting YEARS for this Roguelike — 03:26–05:36; 08:29–11:24; 12:33–15:16; 19:12–19:38; 1:13:50–1:22:00.