[9-7] E1M6: The Door to Chthon

From the start, jump down. To your left is a corridor with a design suspended over lava. Ahead is a door that opens as you proceed, and to the left is another door. Enter the door ahead. Turn right; you will see an obvious, but still hidden door ahead and a room forward and to the right. Walk in front of this room, turn to face away from it, and look up. Shoot the red Q symbol you see. The hidden door, now to your right, will open. Ride the lift up onto the air ducts. Walk to the edge and look down and to your left. You should see the ceiling of the room below. Jump onto the ceiling to find a quad damage powerup.

Go to the room to the left of the design suspended over lava. Push the button with the Q. Fall into the pit that opens behind you. Wait for the stairs to form and walk down them. You will find a passage with a 100 health item at one end and a spiked wall at the other. As you walk down the hall, bars will descend, blocking your exit, a wall will open revealing several ogres, and the spiked wall will begin to approach you. Kill the ogres and escape using a lift that becomes unbarred upon their death. Jump down onto the stairs in the middle of the lava. These are the same stairs you just descended. The bars will eventually retract, allowing entry. This time, the bars will not descend, and the spiked wall will move as soon as you enter. Trigger the wall and retreat. Wait for the wall to pass and go behind it. You will find a slipgate leading to a super nailgun and a box of nails. You can also jump to a landing with a 100 health box.

Below the starting area is a completely dark room that lights up once you obtain the silver key. Cross the pit in this room and proceed to the end of the passage. Turn left to face a set of stairs with a closed door at the top. To the right of the stairs is a column and a large chamber containing a big switch. Activate the switch. Move to the side of the column that faces away from the chamber. A red symbol will have been uncovered; shoot it. The stairs with the closed door will lower. At the bottom, you will find a box of rockets.

Remain at the bottom of the stairs from step #3 until they rise again. A slipgate will be accessible down a small flight of stairs. Walk through it to arrive on a ledge. Across from you, on another ledge, is a 100 health box.