Prelude

The Prelude, also known as the Overture, and known in universe as the Mouth of Hell, is the unofficial layer zero of Hell. Rather than being a part of Hell itself, the layer is actually a mining structure located on the outskirts of Hell. Initially, humanity used the layer to begin exploring Hell. However, when Hell started slowly taking over the layer for itself, the structure was closed off in order to prevent humans from wandering into Hell. After the extinction of humanity, machines began using the Mouth of Hell to enter into Hell proper.

Since the Prelude is the first part of the game, it introduces more common enemies than any other layer of the game. Filths are introduced in the Intro while Strays are introduced in [ 0-1: INTO THE FIRE ]. Schisms wait until [ 0-3: DOUBLE DOWN ] to begin appearing in combat. The creature known as Something Wicked is found exclusively within the level [ 0-S: SOMETHING WICKED ]. The Malicious Face appears as a boss fight at the end of [ 0-1: INTO THE FIRE ] before becoming a common enemy during [ 0-4: A ONE-MACHINE ARMY ]. The Swordsmachine is fought in [ 0-3: DOUBLE DOWN ], although the boss is first seen in [ 0-2: THE MEATGRINDER ] where it can be fought as a secret boss. Finally, Cerberus first appears as the end boss for this layer in [ 0-5: CERBERUS ].

Instant death hazards are more common in Prelude than in layers of hell (excluding the level 2-3). They come in form of crushers, grinders and fans.

As this is the first layer of the game, it introduces the player to a number of mechanics and weapons. The tutorial introduces the player to the fist, sliding, dashing, healing, wall jumping, slamming, and soul orbs. [ 0-2: THE MEATGRINDER ] introduces the player to crushers and is the earliest the player can find a blood orb. The Revolver is introduced at the start of [ 0-1: INTO THE FIRE ], and glass mechanics are introduced shortly afterwards. The Shotgun is acquired by beating either Swordsmachine encounter, with the weapon being almost mandatory for destroying cracks in the wall starting in [ 0-3: DOUBLE DOWN ].

Levels[]

• [ Intro ]
• [ 0-1: INTO THE FIRE ]
• [ 0-2: THE MEATGRINDER ]
• [ 0-S: SOMETHING WICKED ]
• [ 0-3: DOUBLE DOWN ]
• [ 0-4: A ONE-MACHINE ARMY ]
• [ 0-5: CERBERUS ]
• [ 0-E: THIS HEAT, AN EVIL HEAT ]

Enemies[]

Common[]

• Filth
• Stray
• Schism
• Malicious Face

Bosses[]

• Malicious Face
• Swordsmachine
• Cerberus

Other[]

• Something Wicked

Trivia[]

• This is the only layer of the game to:
  • Introduce four (technically six) common enemies.
  • Introduce two (technically three) main weapons.
  • Feature no supreme bosses or enemies.
  • Feature an end-of layer boss that became a common enemy.
  • Had levels with three secrets. (The ULTRA_REVAMP update added new soul orbs)
  • Not feature the map of Hell.
  • Have more than 4 levels.
  • Have instant death traps in every level. _{Honestly, I'm pretty sure there's more in this layer than the entire rest of the game.}
• This layer makes up most of ULTRAKILL's demo, with the levels [ 1-1: HEART OF THE SUNRISE ] and [ 1-S: THE WITLESS ] being added in later.
• An overture is "an orchestral piece at the beginning of an opera, suite, play, oratorio, or other extended composition." This is one example of ULTRAKILL's many musical motifs, like how the final level of a layer will always have "CLIMAX" in its title.