Limbo

Limbo is the first official layer of Hell, as well as the first layer of Act I. The souls in this layer are not guilty of committing any particular sins, but instead are simply those who died without knowing the word of God and are forced to spend eternity within this layer. Limbo is a false paradise where everything within the layer is fake. The trees and grass aren't real, the water is a hologram, the sounds of birds are simulated using speakers, and the sky is just a projection. It is also implied that some of the background music is actually playing on-loop for all eternity. There are hints that suggest residents of this layer can escape, but don't do so out of fear of what lower layers may contain for them. The most notable example of this is Hank, a husk who believed that worshiping Gabriel could get him a ticket into Heaven. Unfortunately, this never happened, and Hank eventually died under the stained glass of Gabriel. Hank also lived next to the entrance to Lust and hid the skulls needed to enter the layer, suggesting that souls in Limbo can pass deeper into Hell.

There are a number of new enemies introduced within this layer. Drones are first seen in [ 1-1: HEART OF THE SUNRISE ], Streetcleaners are first encountered in [ 1-2: THE BURNING WORLD ], and Cerberus first appears in this layer as a common enemy. The first Hideous Mass is encountered in [ 1-3: HALLS OF SACRED REMAINS ], while V2 is first fought as the layer endboss during [ 1-4: CLAIR DE LUNE ]. There are also a number of secret encounters, with both Cancerous Rodent and Very Cancerous Rodent being found in [ 1-2: THE BURNING WORLD ] and the unique Swordsmachine pair Agony and Tundra being encountered in [ 1-3: HALLS OF SACRED REMAINS ].

This layer also introduces the player to a number of new weapons and mechanics. Most notably, skulls are first encountered in the layer's first level. Also found in the first level is the Nailgun, which can be picked up in the next level if the player skips picking it up. Throughout the layer the player can also find hidden stone slabs with roman numerals I-IV, one per level. Pushing all four of them will give the player access to the Alternate Revolver in [ 1-4: CLAIR DE LUNE ]. Finally, in the same level, the player's reward for beating V2 is the Knuckleblaster arm.