Downpour

Downpour is the first new environment added in Repentance. The theme of Downpour is flooded, haunted storm drains with many supernatural enemies and elements. Though there is some overlap with the Flooded Caves due to both featuring water flooding, the Flooded Caves' unique enemies are almost exclusively 'drowned' or 'bloated' as opposed to Downpour's more haunted theme.

Treasure rooms in Downpour always have two items to choose from. One of the items will always be unknown; however, this can be circumvented with the Dream Catcher.

After A Secret Exit is unlocked, a locked door to Downpour I or II will appear upon completing the Basement / Cellar / Burning Basement I or II, respectively. The locked door requires a key to enter.

Unique Elements

Flooded Rooms - A layer of water covers all rooms in the floor, allowing certain enemies such as Small Leeches and Striders to swim over flooded pits. Deep Gapers can hide beneath the water and emerge when all other enemies in the room have been killed. The reflection visible in the water is also utilized by Wraiths, which are always visible in the reflection when they are otherwise invisible.
Lightning Flashes - Lightning will occasionally strike, briefly brightening the room and revealing any Wraiths.

Monsters

Entity	ID	Description
Frowning Gaper	10.0	Walks towards Isaac, dealing contact damage. They start out with their eyes closed, but when they gain line of sight with Isaac, their eyes open and they permanently move faster. Usually turns into a Pacer or with a small chance a Gusher upon death.
Gaper	10.1	Walks towards Isaac, dealing contact damage. Usually turns into a Pacer or a Gusher upon death.
Gusher	11.0	Walks aimlessly around the room, occasionally firing a short-ranged blood shot.
Pacer	11.1	Walks aimlessly around the room.
Fly	13.0	Hovers in place. Does not deal contact damage and is harmless, but can turn into Pooters if they stay around Poop.
Clotty	15.0	Randomly wanders around the room, firing 4 blood shots in the cardinal directions.
Bulb	61.5	Flies in erratic, angled movements toward Isaac if his active item has charges; on contact, they drain up to 2 charges, but never deal contact damage. If he has no active item, or no charges, they wander around the room aimlessly.
Wall Hugger	218.0	Moves around the room like Guts, damaging Isaac by contact. Cannot be destroyed.
Tube Worm	244.1	Pops out of the ground in random locations and fires a long-range spray of arcing shots where Isaac will be.
Bubbles	806.0	Slowly walks towards Isaac, firing back shots upon taking damage. Occasionally farts, which pushes Isaac and adjacent enemies away and creates a chaotic burst of shots. Creates a geyser of water shots upon death.
Wraith	807.0	Walks toward Isaac, dealing contact damage. They are invisible and can only be seen through the reflection they cast in the water, or the ripples they make as they walk.
Willo	808.0	Flies in a circle around Isaac (in formation with other Willos if available), keeping an exact distance away from him. One Willo at a time will occasionally light up and fire a shot at Isaac.
Small Leech	810.0	Chases Isaac continuously, not stopping at walls. Able to swim over gaps.
Deep Gaper	811.0	Emerges from the floor once all previous enemies have been killed, then proceeds to chase Isaac. Deals contact damage.
Sub Horf	812.0	Stationary enemy that spins and fires shots while being moved around or knocked back.
Blurb	813.0	Walks slowly towards Isaac, dealing contact damage. After taking some damage or getting close to Isaac, it fires a chaotic burst of tears at him and chases him more quickly. Can turn into a Pacer or Gusher upon death.
Prey	817.0	Wanders around the room, avoiding Isaac and spawning Small Leeches if he gets close. Spawns 3 Small Leeches upon death.
Strider	814.0	Erratically swims around the room. If it sees Isaac, it chases him, trying to deal contact damage.
Mullighoul	817.1	Wanders around the room, avoiding Isaac and spawning Willos if he gets close. Spawns 1-2 Willos upon death.
Fissure	815.0	Jumps out of pits and bounces around the room. Spawns endlessly from pits until room clear. Do not need to be killed to clear room.
Level 2 Willo	838.0	Orbits enemies and shoots tears at Isaac. If the enemy it is orbiting dies, it will orbit another enemy. However, if all enemies are dead, it will chase Isaac, while still occasionally shooting at Isaac.
Polty	816.0	Picks up and throws rocks and props at Isaac.
Bloaty	879.0	Lumbers around, occasionally spitting green shots and a line of damaging green creep in a random direction.

Bosses


Lil Blub	Wormwood	The Rainmaker	Min-Min

Knife Piece

Downpour II (or Dross II) contains the Mirrored World in which Isaac can acquire the Knife Piece 1, one of the quest items used to access Corpse.

To access this area Isaac can find the White Fire Place which spawns in a single room on the floor. Touching it converts Isaac into a ghostly form, resembling The Lost. Clearing any room will return Isaac to normal.

The ghost form will hold the Holy Mantle if it is unlocked as a starting item for The Lost. The Holy Mantle will not be active until Isaac leaves the room.

While in the ghost form Isaac can then enter the mirror in the 1×1 room with a mirror on the icon, which leads Isaac to the Mirrored World, where he can find Knife Piece 1.

The mirror can be entered normally when playing as The Lost, Tainted Lost, Tainted Soul, or Tainted Jacob in his ghost form after being hit by Dark Esau.

Once Isaac has cleared one room, has obtained the Knife Piece, and returns through the mirror back to the real world, he will be converted back to the original character. After acquiring the first Knife Piece, Knife Piece 2 will now be accessible in Mines / Ashpit II.

For further notes and details see the Mirrored World page

Unlockable achievements

Dross - Defeat all bosses in Downpour.

Trivia

Downpour is referred to on Isaac's Last Will as "Some Sewer".
Antibirth used to have a different method of unlocking first Knife Piece. Somewhere on the floor, there was a seemingly empty dead-end room with a minimap icon that indicated the room had a chest. Bombing the center of the room would open a hidden stone chest containing Knife Piece 1.
In Antibirth, The Haunt could spawn as a boss.
- In Boss Challenge Rooms in Downpour, The Haunt is one of the possible spawns, which is a nod to this.
Gapers and Frowning Gapers are tinted blue if encountered. As well, Clotties that spawn in the floor will appear wet and shiny.
Almost any Spiders that spawn on this floor are replaced with Striders, including those spawned from Red Chests and Shopkeepers. The ones that spawn from a Big Spider are still normal spiders.

Music

The music for the Downpour is called River of Despair.
- An early version of this song was revealed during the pre-release of Repentance, where it was titled "River of Despare".^[1]
River of Despair features heavy use of a theremin, an instrument commonly associated with the paranormal.