Secret Floors Guide (Hidden Chambers)

Enter the Gungeon has a hidden chamber between each main floor (1.5 through 4.5). Defeating any secret floor boss flawlessly does not reward a Meistergeschoss. This guide covers the requirements, step-by-step access, important notes, and first-visit rewards for each one.

Oubliette

Located between Festung des Bleifürsten and Eigentlicher Gungeon. Sewer-style layout full of garbage bags, toxic puddles, and harmless Patroner variants.

Cost: 2 keys (or Verlässliche Dietriche / Bohrer as substitutes)

Steps to enter

1. Festung des Bleifürsten always contains a fireplace room — find the blue water barrel inside or in an adjacent room
2. Push the barrel next to the fireplace to extinguish the flames
3. Crawl into the fireplace and interact with the hidden switch
4. A hidden room with a trapdoor appears on the map — the trapdoor has two locks, each costing 1 key (2 total); Verlässliche Dietriche or a Bohrer can substitute for normal keys

Notes

• Water barrels are fragile — enemy attacks and explosions destroy them, so position carefully during room clear
• If the barrel is gone, use Megaduscher, Kühlmittelleck
• After your first visit, the water barrel usually spawns inside or directly adjacent to the fireplace room on all future runs

Rewards and unlocks

• A small fixed room inside the Oubliette always contains the Altes Wappen, required for the Abtei der Wahren Waffe
• First visit unlocks Müllkanone

Abtei der Wahren Waffe

Located between Eigentlicher Gungeon and Schwarzpulver-Mine. Gothic monastery aesthetic with stronger enemies than the surface floors.

Cost: must first complete the Oubliette and retrieve the Altes Wappen

Steps to enter

1. Pick up the Altes Wappen from its fixed room inside the Oubliette — it occupies an armor slot and disappears the moment you take any damage
2. Carry the Altes Wappen through the rest of the Oubliette and all of Eigentlicher Gungeon without being hit
3. Find the altar room on Eigentlicher Gungeon — it contains seven large bullet warrior statues and looks one cell larger than a normal room on the map; it tends to appear near a shop or chest room
4. Place the Altes Wappen on the altar to open a staircase leading into the Abtei der Wahren Waffe

Notes

• Any hit destroys the Altes Wappen — if you're already low on health when entering the Oubliette, consider whether the escort is realistic
• Some rooms inside the Abtei der Wahren Waffe contain permanently Jammed enemies regardless of your Curse level — they deal and take significantly more damage
• The Abtei der Wahren Waffe always has a hidden room containing Wahrheitsprediger – Brother Albern; opening his chest yields Lügen. This room spawns independently from normal secret room generation, so multiple secret rooms in one Abtei der Wahren Waffe run are common

Rewards and unlocks

• Boss drops both a normal boss reward and a Synergy Chest
• Simply entering for the first time unlocks Blutbrosche and the "Reverence for the Dead" achievement — you do not need to clear the floor

Resourceful Rat's Lair

Located between Schwarzpulver-Mine and Hollow. Mine tunnel layout with no shops and no normal chest rooms. The most complex prerequisites — plan ahead across multiple runs.

Cost: Angefressener Schlüssel + 1 Schlüssel + 2 Nichtss (the Schlüssel can be swapped for Gehülse-Dietrich, AKEY-47, or Verlässliche Dietriche; the Angefressener Schlüssel has no substitute)

Preparation

• Hard prerequisite: the Angefressener Schlüssel does not spawn in the shop at all until you have built the Patrone, die die Vergangenheit abschießen kann. You have to finish the four-component run in Bullet That Can Kill the Past Guide before this route opens up
• The Angefressener Schlüssel first appears in a Eigentlicher Gungeon shop for 1000 Hülsen; payment can be made in installments across runs, and once paid in full it costs 115 Hülsen on every later run. Discount items never lower its price
• The Angefressener Schlüssel can be stolen, but not with Greifhaken or the Steuerkreuz hook (see How to Steal from Shops); if stolen before it has been paid off once, it returns next run at the price it was at
• Six Unverschämte Nachricht are scattered throughout all floors of Enter the Gungeon and appear randomly each run — pick them up whenever they show up. Each note ends with a cheese-wedge arrow indicating one direction in the maze; the more notes you have collected, the more of the correct sequence you know before entering the Lair

Steps to enter

1. On Schwarzpulver-Mine, find a room with 2–4 rats running on the ground and clear it
2. Reveal the hidden trapdoor by walking repeatedly over suspicious floor tiles (a larger-than-normal dust cloud marks the right tile), spraying liquid on the ground, or using a Nichts anywhere in the room — short-range blank effects like Nichtspatronen won't work, and the trapdoor never spawns in a shop room
3. Open the trapdoor with a Schlüssel and drop in
4. Walk along the minecart tracks to the end — do not ride the minecart (riding teleports you backwards repeatedly; walking is faster)
5. Use one Nichts at the dead end to open the first hidden passage. If you have Rüstung, deliberately falling into the nearby pit reveals this passage too, saving a Nichts
6. Walk to the next dead end and use a second Nichts to open the second hidden passage. This one counts as a separate room with no pit, so the second Nichts cannot be saved unless you have another way to hurt yourself
7. Open the final hatch with the Angefressener Schlüssel to enter the Lair

Notes

• Blutiger Schal lets you teleport past both hidden passages, skipping both Nichtss
• The Lair shows only a rat-holding-cheese animation instead of a real map
• Candle-carrying rats wander the floors — harmless normally (they die on contact and sometimes drop Hülsen), but become Jammed and deal contact damage if you carry any Curse
• The maze is a sequence of six rooms, each with a choice of exit direction. Wrong once: sent back to the previous room. Wrong twice: elevator to the Hollow, ending your Lair run
• The correct sequence is fixed per save file and stays the same forever once discovered

Rewards and unlocks

• After defeating the Die Raffinierte Ratte, the reward room has eight pedestals with Herzs, Rüstung, Schlüssels, Nichtss, Gläserner Guonstein, and Munition
• Four special chests in the room require Rattenschluessels and contain Elimentaler, Teilweise gegessener Käse, Raffinierter Sack, and Rattenstiefel. Rattenschluessels only drop during the third Punch-Out phase of the fight, up to six per fight
• The reward room also has a secret room with a snake hidden behind two locked doors — items can be dropped through the second door, so only one Rattenschluessel is needed to feed it
• Feed the snake 4 guns or items and it follows you as a companion until the Drachone fight, where it defects and is absorbed to trigger the Advanced Dragun. That is the route to Löchriger Gral and the "Advanced Slayer" achievement (the other is throwing a Seltsames Ei into fire)
• The snake refuses Schrott-Fernseher, Schwamm, and Verlässliche Dietriche — do not count on those to make up the four
• Alternatively, you can kick the Die Raffinierte Ratte into the snake to feed it
• After the reward room you can proceed to the Hollow normally, or spend a Rattenschluessel to skip directly to the Schmiede
• First visit unlocks Seltsames Ei

R&G Dept.

Located between Hollow and Schmiede. No connection to the other secret floors.

Cost: 1 Meistergeschoss + 2 guns or items (sold to the Verkaufsschleicher in Hollow)

Steps to enter

1. Find the Verkaufsschleicher in Hollow
2. Sell the Meistergeschoss and 2 items — the entrance opens immediately after the third item is sold, so sell the Meistergeschoss last if you want to keep trading first

Notes

• The cost is steep: a Meistergeschoss proves you cleared a boss without damage, and you lose two usable items on top of that
• R&G Dept. has no shop and sparse pickups
• The map outline is deliberately shaped like a handgun; after beating Agunim there is no exit elevator — you have to throw yourself off the rooftop arena to reach the Schmiede
• Only enter when your loadout has clear surplus — if your core weapon or survivability items are borderline, selling them for a bonus floor rarely pays off