E1M3: Toxin Refinery is the third map of Knee-Deep in the Dead. Designed by John Romero, and the par time is 2:00.
From the start point, go through the door in front of you and you will see a nukage pool (be careful, if you fall down into it, you CANNOT get out!!!), a blue door on the right (you cannot go through without the blue key), and an unmarked door on the left. Go through the unmarked door, follow the route to another door you can see, go through it, follow the tan passageway, and turn right. You will see a donut-shaped walkway, overlooked by nukage, carefully cross to the other side without falling down. You should be at a computer-pillar green room. Go north, then east, then grab the blue keycard. Be careful, the light will turn to 35 and a trap containing Imps will open up once you get the key. Now backtrack to the beginning and go through the blue door we left off. You will come to another green room, get to the extreme east of it, then keep going north, into a dark room with lots of monsters. Stairs will raise once you near the exit door, then continue with the new stairway, go through the exit door, and press the switch. If you want to take the secret exit, follow the instructions below.
From the start point, go through the door in front of you and go through the unmarked (northwest) door. Follow the route to the next door, but instead of going through that door, take the first left, then left again, and press a switch that opens up a passage leading to a computer room. Get back to the northwest, you should see a new opening, once you near the computer room, two hidden ledges will lower, quickly get on the northern one. Another technical passage will open, follow it into a room with a slime river. Continue it to the east, to a secret area, and press the switch. Open the different-textured wall to the right and bear right to access a chaingun. A lift will lower, take it back to the room, then backtrack to the beginning. You should see a new-raised bridge near the inescapable nukage pool near the start, continue through it, a passage will open, another door will open, and more doors will open, but beware the monsters in each opening. You can take either the left or right openings, they lead you to an alcove with a passageway that takes you to the secret exit door. Go through it and press the switch.
Other points of interest:
On your way to the northern door, there is a secret door to the right. You can see a portion of one of the openings taking you to the secret exit, however you cannot get into there without the bridge.
If you fall down into the nukage pool at the start or the extreme north/south nukage pools of the donut-shaped walkway, you cannot get out. However if you fall into the middle you can press a switch that will raise the nukage and make the middle of the donut walkway safe and dry.
The yellow key is found at the middle of the computer room, but is only needed to get some items.
The north of the room with the switch that opens another passage is really a lift. Ride it to the top to access an armor.
- The west lowering ledge of the computer room can be open to access a staircase leading to a dark room with a switch that lowers a soul sphere.
- The north lowering ledge can be open to access a rocket launcher.
- There is a slime river, the east tunnel takes you to a backpack and a switch that raises a bridge near the beginning.
- There is a different-textured wall to the right of secret #3, open it to access a chaingun.
- The opening to the secret exit counts as a secret.
- The opposite side of the switch taking you to the secret level, is a tan wall. Pressing it lowers the platform, ride it to the top to get to the ledge where you seen an Imp patrolling the donut walkway.
- The east of the blue door is a different-textured wall that is indeed a door. Opening it takes you to a room with a staircase taking you to some ammo, and a chainsaw. To the southeast of it is a blue door, behind it are two medikits, a megaarmor, a soul sphere and a blur artifact. (on Ultra-Violence and Nightmare!, you want to pick up the blur artifact first because there is a visible courtyard with monsters (it's impossible to get out and pick up their ammo)).