The rooms between destinations supply most of a run's combat, pickups, and active-item charges.
Entry / cost Clear enemies to reopen doors
Watch for A clear does not remove every hazard. Spikes, fires, and some indestructible enemies can still hurt you. Entry, rewards & rules The golden door is a regular source of a new collectible before the late-game floors.
Entry / cost Usually 1 key; first floor is unlocked
Watch for Taking one item from a choice usually removes the other. Skipping the room can help Planetarium chances. Entry, rewards & rules Most floors end with a boss that guards the next floor and a possible deal-room opportunity.
Entry / cost Defeat the floor boss
Watch for Leaving the floor commits you to the next stage. Collect important rewards and check side rooms first. Entry, rewards & rules Spend coins on supplies, utility items, and tools that can improve the rest of the run.
Entry / cost Usually 1 key, then coins for purchases
Watch for Later shops can contain Greed instead of stock. Keep enough keys for your Treasure Room too. Entry, rewards & rules Member Card adds an underground shopping area below the ordinary Shop.
Entry / cost Member Card, then variable coin prices
Watch for Prices vary widely. Read the price before deciding how to spend your remaining coins. Entry, rewards & rules The Stairway offers Angel-pool shopping at the start of a floor.
Entry / cost The Stairway, then coins
Watch for The ladder disappears when you leave the starting room. Check it immediately if you want to buy anything. Entry, rewards & rules Trade health for powerful items, or encounter a different Devil-room layout.
Entry / cost Heart containers or Soul Hearts for deals
Watch for A paid Devil deal usually closes normal Angel-deal access for that run. Check the health price and your route first. Entry, rewards & rules A deal-room alternative with free items and a way to build the Mega Satan key.
Entry / cost Free item choice; optional bomb and angel fight
Watch for Multiple free pedestals usually form a single choice. The optional angel fight still needs enough health and damage. Entry, rewards & rules Look for a hidden room that fits against several accessible rooms on the floor map.
Entry / cost Usually 1 explosion at a hidden entrance
Watch for A location touching several rooms is only a clue. Check whether each possible doorway is physically accessible. Entry, rewards & rules A second hidden room whose position follows a different rule from an ordinary Secret Room.
Entry / cost Usually 1 explosion at a hidden entrance
Watch for Do not use the ordinary Secret Room's multi-room adjacency rule. This room has just one normal-room connection. Entry, rewards & rules A detached secret room reached through the red-room network rather than an ordinary bombed wall.
Entry / cost Red-room access or a special teleport
Watch for Bombing an ordinary wall does not create access. Save red-room tools for promising locations. Entry, rewards & rules Expand the floor into extra rooms and use Home's hidden red door to unlock tainted characters.
Entry / cost A red-room creation effect
Watch for Extra rooms can contain combat. Trying to create a room beyond the map boundary can lead to I AM ERROR. Entry, rewards & rules Reached through a special transition, without an ordinary entrance door.
A rare off-map room that can provide supplies while also taking you past the current floor.
Entry / cost An unusual teleport or out-of-bounds transition
Watch for There is no ordinary return door. An early visit can skip a boss or interrupt your planned completion target. Entry, rewards & rules A small side-view area beneath the floor that can hide an item or a passage to the Black Market.
Entry / cost Find a hidden ladder or create one
Watch for A ladder leads to a Crawl Space; an ordinary trapdoor usually advances the floor. Check the entrance before dropping down. Entry, rewards & rules A side encounter with a deadly sin or a related mini-boss, rather than the floor's main boss.
Entry / cost Defeat the mini-boss
Watch for You cannot rely on bombing a door to escape the fight. Prepare before entering unexplored rooms at low health. Entry, rewards & rules Take the room's reward and accept a multi-wave fight in exchange.
Entry / cost Meet the health gate, then survive 3 waves
Watch for Opening a chest or collecting a pedestal can start the waves. Check your active item before taking the bait. Entry, rewards & rules A low-health entry requirement leads to an item and two boss encounters.
Entry / cost At most 1 total heart to enter; 2 boss waves
Watch for Deliberately reducing health can make the room much harder to survive. An item is not worth losing a promising run. Entry, rewards & rules A timed side objective after Mom awards its own completion mark.
Entry / cost Reach Mom before the deadline; 15 boss waves
Watch for Taking the starting choice begins a long fight. Reaching the door in time does not mean your build is ready. Entry, rewards & rules The large sealed door on the final main-route floors leads to an optional ending boss.
Entry / cost Both Key Pieces or an alternate door opener
Watch for Opening the gate consumes the two Key Pieces. Prepare before committing to the encounter. Entry, rewards & rules A collection of machines and beggars can turn spare coins or health into resources.
Entry / cost 1 coin to enter; machines have their own costs
Watch for Payment does not guarantee a payout. Set a spending limit and keep the health you need for combat. Entry, rewards & rules Pay damage at a spiked doorway for a chance at unusual pickups and items.
Entry / cost Half a heart each way; a full heart from Womb
Watch for Budget for leaving as well as entering. Flight avoids entry damage, but does not remove exit damage. Entry, rewards & rules A room of books can offer an active item and progress toward Bookworm.
Entry / cost Usually 1 key
Watch for Picking up a book replaces your current active item unless a special inventory effect lets you carry another. Entry, rewards & rules Repeated payments to the central spikes progress through a fixed reward sequence.
Entry / cost Normally 1 full heart per successful spike activation
Watch for Later payments can spawn troll bombs, start angel fights, or move you to the Dark Room. Count each activation. Entry, rewards & rules A bed provides recovery, and the clean carpet hides an entrance beneath the floor.
Entry / cost 2 explosions to open the boarded door
Watch for Clean and Dirty Bedrooms have different carpet exits. Confirm which room you entered before using the opening. Entry, rewards & rules A useful healing room whose carpet hides a next-floor exit rather than a Crawl Space.
Entry / cost 2 explosions to open the boarded door
Watch for The trapdoor skips ahead. Finish your boss, purchases, and route objectives before using it. Entry, rewards & rules A double-locked side room offers a collection of chests or loose resources.
Entry / cost 2 keys
Watch for Opening the door can leave you without keys for the Treasure Room or Shop. Chest rewards vary. Entry, rewards & rules The number of pips tells you whether the center rerolls pickups, items, your build, or the whole floor.
Entry / cost 2 keys; optional one-use reroll
Watch for One and six pips can replace your build. Five pips restarts the floor. Read the effect before touching the center. Entry, rewards & rules A rare item room rewards players who understand how skipping Treasure Rooms affects its chance.
Entry / cost 1 key after the room is unlocked
Watch for Skipping a guaranteed Treasure Room trades an immediate item for a chance at a later Planetarium. Entry, rewards & rules Entered through a side passage inside a Crawl Space.
A hidden market connected to a Crawl Space sells Shop items for health.
Entry / cost Heart-container purchases
Watch for A direct teleport can leave no return passage. The floor exit can skip unfinished objectives. Entry, rewards & rules Silver Greed-mode doorway
Greed mode's silver room supplies a free item alongside the separate locked golden room.
Entry / cost Unlocked in Greed mode
Watch for The silver and golden rooms use different pools. Taking one choice item usually removes the other. Entry, rewards & rules Devil's Crown changes unvisited Treasure Rooms into rooms offering Devil deals.
Entry / cost Devil's Crown; heart-price item
Watch for Buying an item counts as taking a Devil deal. This can change normal Angel-room access. Entry, rewards & rules Downpour / Dross · +3 variants
Special doors after boss fights connect the main route to Repentance's alternate path.
Entry / cost Key, 2 explosions, health, or completed knife
Watch for The Mausoleum/Gehenna door costs two hearts. Plan both health and the Knife Piece checkpoints before committing. Entry, rewards & rules The mirror on Downpour/Dross II is the route to Knife Piece 1.
Entry / cost Ghost-form entry; mirrored-floor combat
Watch for Keep the mirror intact. Destroying it cuts off traversal and can end the run if you are inside the mirrored world. Entry, rewards & rules The cart on Mines/Ashpit II leads to the chase sequence for Knife Piece 2.
Entry / cost 3 rail plates or an alternate opening
Watch for Mother's Shadow pursues you on the way back. Prioritize movement and a safe escape. Entry, rewards & rules A large pit in Corpse II takes you into the final Mother encounter.
Entry / cost Reach Corpse II
Watch for The pit commits you to the fight. Collect remaining resources on Corpse II first. Entry, rewards & rules Return to the start of Depths II to begin the Ascent route toward Home and The Beast.
Entry / cost The Polaroid or The Negative, plus a way back
Watch for The door consumes the photo. Keep a teleport out of Mom's room instead of immediately taking the floor exit. Entry, rewards & rules Timed opening after the Heart
A timed opening after the Heart leads to Blue Womb and Hush.
Entry / cost Defeat Mom's Heart/It Lives! before 30 minutes
Watch for The door remains time-sensitive. Enter before the deadline, and make sure the build can handle Hush. Entry, rewards & rules Blue Key inserts a Blue Womb-themed fight when you attempt to open a paid door.
Entry / cost Blue Key; clear an intermediate enemy room
Watch for This is extra combat on the way to the room. It does not take you to the Hush floor. Entry, rewards & rules The southern room in Greed mode holds the route to the next floor.
Entry / cost Finish the required floor waves
Watch for The exit cannot be forced open with bombs. Finish shopping and collecting the floor's items before descending. Entry, rewards & rules The dirt patch in the Dark Room is the last step of The Forgotten's unlock quest.
Entry / cost A digging effect; Mom's Shovel for the unlock
Watch for A generic digging effect can reveal a chest, but The Forgotten's unlock specifically needs Mom's Shovel. Entry, rewards & rules