The Black Market is an area in the Gungeon, the entrance to which may rarely generate on any floor except the Resourceful Rat's Lair, the R&G Dept, and Bullet Hell. It is an area hidden off of the main map containing multiple merchants and one of Winchester's shooting ranges, all operating with significant discounts.
The entrance to the Black Market takes the form of a large green 'Demon Face' in the wall of a room. If the player has at least 100 or 1 Curse, they may access the Black Market by walking into the mouth of the Demon Face. If the player does not have the required money or curse, entering the Demon Face will deal one damage to them and spit them back out.
Once the Market has been visited, the Demon Face will disappear. The player may still access the Black Market however via a teleporter on the map. This access will not be revoked even if the player's curse drops below 1 or their count drops below 100.
If the player shoots the Demon Face in its mouth with a gun that creates a pool of water the Demon Face will spit out a random or quality gun or item. The Demon Face will still function after this, so it is highly advisable to do this before entering.
- Guns that trigger this effect are: Mega Douser, Siren, Barrel, Glacier, Bubble Blaster, Bubble Lead, Starpew and Tear Jerker.
- This does not work with liquids other than water, such as poison.
- This also does not work with a water barrel.
The Black Market contains Old Red, Cursula, Professor Goopton, and Flynt inside of its main room. They will each have three items for sale from their regular pools (except for in Rainbow Mode where their wares will be empty).
All of these merchants will sell their wares at half price, except for Flynt whose key based prices do not change.
A corridor at the eastern end of the Black Market leads to a bonus Winchester game, where the entry fee also has a 50% discount.
- If the Lord of the Jammed is allowed to enter the Black Market, all Merchants will immediately stop selling their wares.
- Merchants can appear in the Black Market even if they have already appeared on the main floor, creating a duplicate.
- If the player is asked to map out a floor containing a Black Market by the Lost Adventurer, the map will not be considered complete until the market is explored.
- The layout of the Market never changes.
- Rarely upon entering a Demon Face, it's eyes may open wide and stare down at the player with a surprised expression.
- Demon Faces are a reference to Demon's Mouth from the classic Dungeons and Dragons Adventure Module Tomb of Horrors.
- The spraying of water into the demon's mouth can be a reference to either the saying "People in hell want ice water" or to the parable of Lazarus and the Rich Man in the Gospel of Luke (which may or may not be connected). It could also be a reference to the classic carnival game where you shoot water into a porcelain clown's mouth to make a balloon pop and get a prize. It also may be a reference to the boss Zehnoa from Trials of Mana, an infamously strong boss where the key to beating it is extinguishing its flames in its mouth.