Prior to the 20th Anniversary Edition
When you drop down the hole into the room before the Battlelord, turn 90 degrees to your right, and walk around to the other side of the column. A hidden compartment containing ammo for the Chaingun Cannon will open. Behind the back wall of this compartment, there is an exit button. This exit button serves as the normal exit during multiplayer, but it can also be reached during singleplayer by exploiting cheats. Specifically, using the no-clip cheat ("dnclip") will allow the player to pass through the wall and hit the exit button.
Hitting the exit button will take you to Launch Facility. However, if you complete Launch Facility, then you will be brought back to The Abyss, and if you hit the exit button again, then it will instead take you to Faces of Death, a level that cannot be completed (prior to Duke Nukem 3D: 20th Anniversary World Tour, Faces of Death did not contain an exit button) and was not supposed to appear as a singleplayer level in the final game.
20th Anniversary Edition
In the 20th Anniversary Edition, this exit button appears as a secret exit button, and it can be reached without using cheats, by simply opening the back wall of the hidden compartment described above. This secret exit button will take you directly to Faces of Death, which can be completed normally in this version of the game.
Secret 1: Top of the stairs
Upon reaching the ruins, there is a set of stairs leading up to a fire pit. At the top of these stairs, there is a protrusion in the left-hand wall, just before the fire pit (A box of Pipe Bombs can be found to the right of this protrusion). Opening the front of the protrusion will reveal a secret compartment with Steroids inside.
Secret 2: Teleporter in the fire pit
Inside the ruins is a fire pit with bloody handprints on the surrounding walls. Touching the fire will damage the player's health, but stepping into the center of this fire pit will teleport the player to a different fire pit in a secret area. After claiming the secret, it is possible to return by stepping back into the fire pit.
Secret 3: Secret ledge inside the secret room
In the secret area from Secret 2, there is a ledge with RPG ammo in a poorly lit corner of the room. Jumping onto this ledge is counted as another secret.
Secret 4: Crack at the top of the lavafalls
In the lava just past the ruins, there is a slightly obscured opening on the right-hand side of the canyon that leads to some lavafalls. Climb to the top of the lavafalls. Along the right-hand walkway at the very top of the lavafalls, there is a crack in the right-hand wall. Blasting through this crack will lead to an area from earlier in the level. The top of this passageway is counted as a secret.
Secret 5: Dancing shaman
At the top of the lavafalls, there is a rock in the middle of the lava stream. Jump onto the rock. Above the rock, there is a bloody handprint. Pressing the bloody handprint will reveal a hidden passage. Inside, a woman in tribal garb can be found dancing beside a fire pit with three Atomic Healths nearby.
Secret 6: Outside the Battlelord's spaceship
Near the end of the level, there is a giant silver door that leads into the Battlelord's spaceship. While facing this door from the outside, turn right. There is a bend in the wall here, and to the right of this bend, there is a section of wall that can be opened. Opening the wall reveals a pathway up to a secret area along the exterior of the spaceship.
Note: This secret was added in Duke Nukem 3D: 20th Anniversary World Tour
Just outside the door to the Battlelord's chamber, there is a circular room. Walking around the perimeter of this room will cause compartments in the walls to open automatically. While facing the door, the compartment on the right-hand side can be found to contain Chaingun Cannon ammo. The back wall of this compartment can be opened to reveal a secret compartment with a secret exit to Faces of Death.
The following hidden compartments are not counted as secrets:
- Still in the ruins, before Secret 4, after being shrunk and escaping through a hole in the ground and returning to normal size, there is a small waterfall/fountain. Go through it and end up in a room with some goodies.
Piece of Cake: Finishing the Level on any difficulty unlocks this achievement.
- Past the Blue Access Card Panel near the beginning of the level, using the Night Vision Goggles inside the dark passage will reveal the words, "Go with the flow," written on the left wall.
- High up in the alcove that fires Shrinker beams, a message on the wall reads, "You're not supposed to be here." The message is signed, "Levelord," an alias used by level designer Richard Gray.
- In the secret area with the dancing girl, there are some hidden letters on the right wall that read, "SUYT." This is an acronym for "show us your tits."
- When approaching the Battlelord's spaceship at the end of the level, there is a section where the player must leap from platform to platform, high above a pool of lava. Along the very bottom of the first platform is a message that reads, "DOPEFISH LIVES." This is a reference to a character from Commander Keen. However, it may also be a reference to a scrapped cheat code; purportedly, the developers had originally programmed a cheat code into the game that would change all the Sharks into the Dopefish. The cheat code was scrapped when the Sharks were removed from the game shortly after the May 1995 prototype, but the Sharks were eventually added back to the game in the final months before the game's release.
To satisfy Nintendo's adult content standards, the Easter eggs on this level were censored in the Nintendo 64 port. In Duke Nukem 64, "You're not supposed to be here" and "SUYT" have been removed, and instead of "DOPEFISH LIVES," it says, 'WHAT'S YOUR BEEF SPECCY."
- This level contains an exit button that can be used to reach Faces of Death. Except in the 20th Anniversary Edition, it is not accessible without cheating. See the "Redundant Exit Buttons" section of the exit button page or see the Faces of Death page for more information.
- With strafe-running or Steroids, it is possible to re-enter the boss door before it closes all the way. It will not re-close, allowing you to fight the boss from the elevator room.
- The fight with the Battlelord at the end of this level is referenced in the Duke Nukem Forever opening.
- This is level with the most Atomic Healths in the game, having 14 of them.
- It is the only level in the entire game where ammo and health is affected by higher skill levels: on skill 3, an extra pistol clip, two shotgun shells boxes, five chaingun ammo boxes, and two RPG rockets crates appear.