E1M4: Sludge Factory (No Sleep for the Dead)

E1M4: Sludge Factory is the fourth map of No Sleep for the Dead. It was designed by Jan Van der Veken and uses the music track "The Imp's Song" by Bobby Prince.

Essentials
Follow the S-shaped path past some zombiemen and imps until you reach a door and go through it. Turn left at the junction and go up the stairs on your right, then turn left and left again and follow the passage until you reach an area with a blue floor. West of this floor is a small chamber containing a switch - press it and head back down the stairs, watching out for some demons that have been released from a closet on the way. At the bottom of the stairs, kill any approaching imps (plus two shotgun guys on Hurt Me Plenty (HMP) skill level or higher) then go through the nukage and head west through a doorway. Follow the path round and collect the red keycard at the end.

Return to the junction and go south into another nukage pool, then open the door on your right which has red key markings. Head straight forward into more nukage and press the switch on your left, then leave the nukage and head south up some stairs. Follow the corridor through a lit doorway to encounter one to three cacodemons, then head north through another doorway and climb the stairs that rise in front of you. Kill the imps waiting at the top and follow the path to the blue keycard.

You need to backtrack to the junction again - retracing your steps through the red key door is safer, or you can drop through the nearby window which is faster but opens three alcoves containing monsters. Back at the junction, climb the south stairs and turn left at the top, then turn right and head down some steps past a shotgun guy. When the passage curves to the right, kill the monsters guarding a chaingun and a box of bullets then turn left and go through the door with blue key markings. Kill the waiting shotgun guys and head forward to the exit door, open it and press the switch to finish the level (on Ultra-Violence (UV) and Nightmare (NM) skill levels, the switch is guarded by a cacodemon).

Other points of interest
A chainsaw can be found behind a doorway next to the blue key. The weapon is guarded by a shotgun guy on HMP or higher.

North of the blue key door is a large lift. Ride it up to a passage with computer panels and follow the path to a megaarmor guarded by some imps. Approaching the megaarmor will cause the passage to darken and open several alcoves containing imps and shotgun guys, plus three spectres on UV or NM.

Secrets

 * 1) A dead marine is in the nukage pool on your left at the start. Go past it to find a shotgun. (sector 0)
 * 2) Open the door at the end of the walkway at the start, then go left and up the steps on your right. Next to the dead marine and shotgun shells, open the wall here to get four armor bonuses and a medikit. (sector 199)
 * 3) Go towards the T-shaped blue-floored room at the north end of the map and climb to the top of the steps, then backtrack to see monsters emerging from another blue-floored area to the south. Throwing the switch in this section allows access to the rocket launcher visible through the window. To get to it, head west from the switch back to the T-shaped room and through the open passage ahead. (sector 151) Follow the passage to a door, and go through to collect the weapon.
 * 4) After getting the rocket launcher past secret #3, head east into the nukage and follow the tunnel to find rockets, medikits, a computer area map, a box of bullets and a chaingun. (sector 229)
 * 5) In the room with the red key, open the gray wall in the south-west corner to find six health bonuses. (sector 92)
 * 6) Next to the big lift at the east end of the map is a small passage leading to a partial invisibility powerup. (sector 270)
 * 7) Next to the chaingun by the blue key door is a switch - press it to lower a wall across the nearby nukage and reveal a soulsphere, plus a radiation shielding suit on HMP or higher. To reach it, first climb the stairs next to the nukage in front of the red key door and turn right to see a second switch. Flip this switch to open a wall in the south-east corner of the nukage, then enter the nukage and follow the passage until you reach the secret. (sector 187)
 * 8) Going east from secret #7, continue along the nukage and around the exit to find a box of rockets, a box of bullets, and a box of shotgun shells. (sector 242) Another radiation suit can be found here on HMP or lower.

Current records
The records for the map at the Doom Speed Demo Archive are:

The data was last verified in its entirety on December 12, 2021.

Things
This level contains the following numbers of things per skill level: