Dark Deception: Unchecked Limitations/Hidden Nightmares

The Hidden Nightmares are bonus levels in Dark Deception: Unchecked Limitations. They are extra-difficult levels that are completely optional in the story mode but are required in order to obtain Cosmic upgrades. There is at least one Hidden Nightmare in every Chapter. The Hidden Nightmares can be played at any difficulty except for easy mode.

How to Get
Obtaining an A rank or S rank in all levels within a single chapter will automatically unlock the Hidden Nightmares present within that Chapter. However, the Hidden Nightmares can also be unlocked earlier through hidden secrets found in the main-story levels, which may prove more useful if one wants to obtain Moon Charms before attempting an S rank playthrough.


 * Wreckage Warehouse is unlocked if the player interacts with a forklift parked in the underground garage in Monkey Business. Note that to obtain the secret the player must fight Killer Kong.
 * Egyptian Epidemic is unlocked if the player goes into the upper floor of Elementary Evil's Zone 2, in which there is a secret room containing excursion and incursion schedules for the school, one of which is a planned excursion to Egypt.
 * Feral Flora is unlocked if the player finds and collects six flowers hidden within the hedge maze of Deadly Decadence. These flowers are colored Red, Orange, Yellow, Green, Blue, and Purple.
 * Melodramatic Museum is unlocked if the player finds a secret room in the Ruined City of Stranger Sewers. This is a non-aggressive Haunted Painting that emits an aura of darkness and feminine whispering. A similar room can be found in the Swamp if the player took the alternate route.
 * Gory Greece is unlocked if the player either finds a cage in the alternate route containing a sleeping Fallen Gladiator or in the normal route a graffiti of the Lavastorm Demon in the funhouse.
 * Experimental Extinction is unlocked if the player finds and speaks to the Professor after the defeat of the Head Surgeon in the alternate route. In the normal route, the player instead can find the Professor's notes, specifically on the Bacteria.
 * Outerspace Obliteration is unlocked if the player spots a flying UFO in Bearly Buried. The UFO looks to be the same as those used by the Plutonians.

Trivia

 * Originally, Wreckage Warehouse, Egyptian Epidemic, Melodramatic Museum, and Gory Greece were going to be the only levels in Dark Deception: Unchecked Limitations that doesn't have alliteration in the title, much like Monkey Business from the base game. The original names for these are:
 * "Wary of Danger" (Wreckage Warehouse)
 * "Sands of Chaos" (Egyptian Epidemic)
 * "The Art of War" (Melodramatic Museum)
 * "The Grave of Champions" (Gory Greece)


 * In this version of Dark Deception, when a nightmare collapses it can be rebuilt.
 * Mascot Mayhem is currently the first and the only level in Dark Deception: Unchecked Limitations that doesn't have an unlockable Hidden Nightmare.
 * There's an achievement where you comfort a traumatized-looking Birthday Boy Blam on Mascot Mayhem, although it doesn’t unlock the Hidden Nightmare yet. The dialogue where he mentioned a puppet master could be a foreshadowing of the characters and setting for Mascot Mayhem's next Hidden Nightmare, which will soon be revealed in a future update.