Mirrored World

*(chapter 1.5)*

The **Mirrored World** is a special area of the Downpour II and Dross II. The layout of The Mirrored World is the exact same as the normal floor, except mirrored left to right. Each room contains the same enemy encounters and has the same block layout, although some rocks may be different. The Treasure Room of the Mirrored World contains . The boss is also identical, and, if defeated, will drop an item from the Boss item pool.

## Accessing the Mirrored World

In Downpour II or Dross II, there will be a room with a mirror on the side of a wall. In another part of the map, there will be an inextinguishable white fire. Touching the fire will cause the player to "die" and take control of  The Lost. This state allows Isaac to pass through the mirror and access the Mirrored World.

## Notes

* The Mirrored World is covered in a shimmery overlay, and its graphics slowly warp. Additionally, items and pickups will have their artwork inverted, and the level's soundtrack is played backward.
* Breaking the mirror is possible with a bomb, but it's not recommended as it will cut off access to the Mirrored World.
	+ Breaking the mirror while inside the Mirrored World will cut off access back to the normal world. Isaac will begin to fade and eventually start taking damage. Extra lives cannot be used to prevent this, as Isaac will continue dying after using an extra life.
	+ The mirror will also break if  is used in the mirror's room.
	+ or  can break the mirror.
	+ will break the mirror upon entering the room.
* On XL floors, only one of the Treasure Rooms will contain Knife Piece 1 - the other will be empty. Both Boss Rooms will contain a treasure as normal.
* All Secret Rooms, Shops, and Vaults will be devoid of items. However, Shopkeeper will still appear, and can drop items as normal.
	+ The  trapdoor will appear in the shop, and will lead to an empty store.
	+ will spawn rerolled versions of whatever was initially in the room in the normal world; that includes any pickups, chests, and pedestal items.
	+ Using the Shop Restock Machine in the shop in the Mirrored world will make items appear in the mirrored shop. The normal shop will not be rerolled, and subsequent rerolls will not match those of the mirrored shop.
* If the location of a secret room or super secret room was first discovered in the mirror world, its location will be mapped when returning to the normal world, and vice versa.
* Trapdoors will not be spawned, except to crawlspaces or Black Markets – which will have no items.
	+ Black Markets can be populated with a Shop Restock Machine. Items purchased from a mirrored Black Market are considered to be purchased by the non-mirrored character rather than The Lost; multiple items can be purchased and the health will be deducted from the non-mirrored character, possibly resulting in death.
		- However, if items are bought via  in a mirrored shop while in  The Lost form, all those items are free. No health is deducted from the non-mirrored character. This is also true of items restocked from a  area *if* that area was only visited in the Mirrored World, such that it was initially empty and then restocked (e.g. if Member Card were purchased in the Mirrored shop then immediately accessed). Caution is advised; while the items are free in this unique scenario, the spikes around pickups will still kill  The Lost form. Subsequently going back to the non-mirrored member card area will also leave items/pickups restocked from the mirrored world on top of the original non-mirrored spawns. This is probably a bug, as the area is meant to be the same.
	+ The use of  will teleport the player to a room without trapdoor, where they can only pickup items. Note as well that there isn't any bed, nor a mirror inside.
* Wraiths will appear visible, but they will lack reflections unlike other entities, opposite of their normal appearance.
* The rooms in the Mirrored World count as separate rooms, so anything that happens in the normal world room will not affect the mirror world variant of the room, and they drop their own pickups upon completion.
	+ Using a  card in the mirrored world is not recommended, as it will teleport Isaac to an empty version of the Devil Room or the Angel Room, causing the card to be wasted.
* The Lost and  Tainted Lost can pass through the mirror normally.
	+ Tainted Jacob can enter the mirror if he has been touched by Dark Esau.
	+ Tainted Soul can also enter the mirror without a white fire, and in turn, keep his health bar.
		- The mirror can even be entered by throwing  Tainted Forgotten at the mirror.
		- Even though Tainted Soul can enter the mirror,  The Soul cannot.
* It is a viable strategy to visit Downpour II / Dross II and enter the mirrored world even when not wishing to reach Mother, as it guarantees an extra Boss Room item and various pickups from clearing rooms. This is a risky strategy, however, as  The Lost can still die easily.
* If a Planetarium or a Library exists in the normal world, it will exist in the mirrored world and require a key to open, even if it's opened in the normal world. However, there will be no items.
* To turn back into the original character, it's required to clear 1 room as  The Lost. If Isaac is in the Mirrored world, he will turn back after going through the mirror if he has not gone through it already. If there are no rooms left on the current floor, he could clear a room on the next floor and turn back.
* Any means of spending blood, including Blood Donation Machines, Devil Beggars, and Hell Games, will result in an immediate death, even if the non-mirrored character has health to spend.
* Using  will transform Isaac back to his normal form with normal health, potentially making surviving the mirrored world much easier. This does not prevent leaving the Mirrored World normally via the mirror.
* When using any revival items while in the Mirrored World, such as  or , Isaac's health will still be affected by the revival item used, even though the character in the Mirrored World is the Lost. For example, dying with Dead Cat will set the character's health to 1 red heart, regardless of the player's health in the non-Mirrored World.
* The mirror cannot be entered if the player uses  or .
* A Dice Room in the mirror world is distinct from the other Dice Room, is activated separately, and may have a different number.