Doom II: Hell on Earth/MAP05: The Waste Tunnels
The Waste Tunnels is composed of two sections. The first is the brightly lit base, and the second is a darkened area. Even though you would expect it, there is no nukage or damaging floors within this level.
At the start, you can either get the shotgun (on easy difficulty) or super shotgun (medium and hard difficulty). Almost immediatly after exiting the starting location, you will be attacked by Sargents on the right-hand side, and chaingunners on both sides. In this room, approaching the floor between the two torches will lower a platform, either to the central courtyard or some ammo/health closets. If desired, the green armor is in the north-western closet.
To continue, head to the door to the left. Instead of the door opening, the floor will lower to the next area.
 Red Key
After entering the dark area, you will see the red key in the distance. Imps will be in the darkened area, and will approach. From here, there are three routes to take; with the center and right-hand route leading to the key.
The northern path, marked by an arrow leads to a corridor filled with imps, and doors opening from behind as you progress. The end of the corridor contains additional shotgun shells, and a second soul sphere.
When you take the center path, you will enter a room with former soldiers. The major threats are the sergeant and chaingunners watching the lift, located at the beginning of the room. You can collect ammo from the enemies within the room, if desired; a box of rockets and shells can be found on the northern section. Proceed down the right corridor to continue.
If you choose the right path, a door will close behind you. To escape, open one of the doors on the left hand-side. The left-most door contains a switch that opens the entry door. The central door opens a monster closet, which contains blue armor. The right-most door opens a shortcut on the other side.
Once you enter the southern tunnels, head to the right to reach the red key. Other items in the tunnels include a rocket launcher, located in the center room, and a few medikits, through the door on the south-west corner.
Return to the west via the tunnels to continue.
 Reaching the exit
As soon as you open the red key door, you will see the blue key; it's guards include a hell knight, a chaingunner, and two imps. Get the key and continue past the other red key door.
The blue key gate is to the left, and you should immediately see the yellow key through a window. Loop around, get the key and cross the raising bridge to reach the exit. Once you head to the key, Cacodemons will be released and try to attack.
- After entering the dark area and following the arrow, you should see a soul sphere. Open the door behind it to reveal a berserk pack. (Sector 92)
- From the blue key area, head north to the side room overlooking the courtyard. Use the north wall to lower it, and run forward to the alcove before it's lift raises back up. This area contains a plasma gun. (Sector 94)
- Head behind the exit for a box of rockets and shells. The easiest way is to clear the water pit of demons, and do a running jump or strafe jump from the side into either of the cacodemon alcoves. (Sector 153)
- A BFG is added at the exit.
- Light amplification goggles are places at the red key.
- Two invisibility charges and one invulnerability charge is found in the 3-switch room.
In the three switch room, when no monsters is enabled (usually from multiplayer), Opening the south-western most door first will permanently lock access to the blue armor and the exit-alcove secret.