E1M6: The Door to Chthon

The Door to Chthon is the sixth level of the Dimension of the Doomed. Filled with deadly traps and obstacles to overcome, this fortress-like level is the final challenge for those that seek to access the The House of Chthon. Many of the monsters are not visible from the start and appear later - either teleported or dropped from hidden compartments.

In this level the player must find both a Gold Key and a Silver Key in order to proceed. Apart from several Lava pools, the deadliest trap players will face is a moving Spiked Wall in one of the corridors.

Quick Level Completion

 * Drop to the central room.
 * Follow the corridor to the left and press the Floorplate at the end.
 * Cross the opened doorways to a Button.
 * Drop through the hole in the floor.
 * Wait for the stairs to drop, then enter the next corridor.
 * Kill all enemies so the door will unlock.
 * Go through the door at the end and take the Elevator.
 * Collect the Silver Key and take the Teleporter at the end.
 * Turn around and follow the corridor.
 * Press the Button at the end, raising the platform to the Silver Door.
 * Open the Silver Door and press the Floorplate.
 * Return to the central room and collect the Gold Key.
 * Open the Gold Door in the central room and press the Button to the left.
 * Follow the opened door to the next Button.
 * Follow the next opened door to the exit.

Walkthrough
From the start collect two 25 Health, Shells, and Rockets. Drop down to the bottom of the platform and kill the Ogre. Collect the Nails and 25 Health by the Elevator. To the right is an inaccessible Gold Key on a platform across a passageway of Lava. In the middle of this room is the Gold Door. There are 2 darkened passageways to the left and back. If you go through the back one, you most likely will fall and get hit by the Nail Traps below. Thus hit the Floorplate to turn on the lights in the left passageway, and to open a Door at the end. As you approach an Ogre will come out of the opened doorway. Turn right and collect two 25 Health and Rocket Launcher. Step in the next doorway. Turn around and look up to shoot a Button to open a Wall to your right. Ride the Elevator inside to the top, and look in between the turns for a ledge to jump to in between floor and present alcove level  (#1) . Drop to the floor and go into the next room. The Door on your right has opened to allow you to return to the start of the left passageway. Collect the Shells and press the Button to open a Door on the opposite side of the start of the left passageway. Collect the Yellow Armor and press the Button. A Wall alcove opens with an Ogre and 100 Health inside, though they cannot be reached from your present location. Drop through the newly opened hole in the floor and kill the Ogre to the right on the ledge. After a second the floor will drop and create stairs to go down. Collect 25 Health and Rockets, and beware of the Lava to the sides of the stairs. Go down the stairs and turn right. Be fast as the way you entered will close and you will be locked in with a Large Wall Spike. Kill the Ogre as the Wall opens up and pushes him out to the left. This opens a Door to the right, but be sure to collect 100 Health at the end first. Use the Elevator and turn right onto the ledge overlooking the Lava stairs. Turn left and collect the Nails, then follow the passageway around, collecting two 15 Health and the Silver Key. A message will say "Your way has been lit" and a locked Door at the end of the passageway will open. Continue on the passageway to collect the Shells, but don't turn right and enter the Teleporter that leads back to the lower level of the starting room. Instead turn left and drop back to the Lava stairs. Wait for the Large Wall Spike to pass to the right, and then go left into the Teleporter (#2) . Collect the Super Nailgun and Nails while killing the 3 Scrags to the right. You are now above the doorway in between the start of the left passageway and the Yellow Armor room. From here, you can jump to the alcove with 100 Health you couldn't previously reach.

Return to the lower floor of the starting room, where you would have gone if you had used the other Teleporter. The back passageway is now lit. Cross the thin platform, and beware of the 7 Nail Traps at the bottom if you fall while trying to get to the Teleporter behind you. Once you successfully get across a Wall alcove will open up with an Ogre and 25 Health inside. Just before the alcove is a Door to the left. Beware the Lava to the left. Straight is a locked Door, but to the right of it are two 25 Health. To the right of the entrance are Rockets. Another room is to the right with Nails and a Button. A platform will rise out of the Lava leading to the Silver Door on the other side. Also 3 Zombies will drop from the ceiling into the room. Hit the Button on the pillar to open the stairs leading to the locked Door, revealing an alcove with Rockets  inside  (#3) . If you wait a second for the stairs to close, a Teleporter will be revealed behind the stairs you climbed down to get  (#3) ,  (#4) . Once done, open the Silver Door and collect the two 25 Health. Press the Floorplate to create a platform to the Gold Key, which you may now return and get, but first stopping by the doorway that was locked at the top of the staircase to  (#3)  to collect Nails, and enter a Teleporter leading back to the bottom of the starting room. Open the Gold Door, kill the Ogre, and collect the Shells. Press the Button on the left to open the Doors to the right. Collect the two 25 Health, Nails, Rockets, and Super Nailgun in the next room. Press the Floorplate to the left to open a Door just in front of it. As the lights come on collect the Yellow Armor and kill the Shambler. Return to where the Shambler was and jump into the Teleporter in the floor to exit the level.

Differences from Easy to Normal

 * Ogre to left of entrance to left passageway by the Door leading to the Yellow Armor.
 * 2nd Ogre on alcove with 100 Health
 * Ogre on front side of ledge overlooking Lava stairs
 * 2 Ogres initially in Silver Door room
 * 4th and 5th Zombie  in Silver Door room when Button is pushed
 * An Ogre by the Elevator in start room after Floorplate is pushed for raising the platform to the Gold Key.
 * Fiend spawns when you grab the Gold Key
 * 2nd Ogre  behind Silver Door

Differences from Normal to Hard/Nightmare

 * Ogre initially by Elevator by start area
 * Ogre on left side of ledge by Lava stairs
 * 2nd Ogre  gets pushed out in Large Wall Spike room
 * Ogre spawns straight ahead in Large Wall Spike room
 * Nails by Super Nailgun in  (#3)  moved to 100 Health in the nearby raised alcove.
 * The 2 Ogres are moved closer to the Button that raises the platform to the Silver Door.
 * Fiend initially in Silver Door room
 * 6th Zombie  in Silver Door room after Button that raises platform is pushed
 * Fiend behind Silver Door
 * Shambler spawns instead of Fiend when Gold Key collected
 * Only Nails and a 25 Health in second to final room

Glitches

 * The player may Grenade Jump or Rocket Jump to the Gold Key from the starting room.
 * The player may Rocket Jump to the silver key to bypass the spike wall.

Differences

 * No 25 Health by starting Elevator
 * No Rocket Launcher in left passageway from start
 * Double-Barrelled Shotgun by Lava stairs
 * Rockets in Large Wall Spike room
 * Yellow Armor replaces Silver Key, no two 15 Health beside, Rocket Launcher further on ledge
 * Standing beside Teleporter in area where Silver Key used to be causes "your way", the corridor leading to the silver doorway, to be lit.
 * Nails by Super Nailgun in  (#3)  moved to 100 Health in the nearby raised alcove.
 * Double-Barrelled Shotgun in Button room raising platform to Silver Door.
 * Only 25 Health past the Silver Door.
 * No wall separating the Floorplate from where the Gold Key used to be
 * Gold Key replaced by Yellow Armor
 * Super Nailgun by exit Teleporter

Spawn Locations

 * Button to silver doorway
 * Left side of platform with Silver Key
 * Room below  (#1) 
 * Room with Floorplate to exit room
 * Bottom of Elevator of start room
 * By  (#3)  Button
 * Room below Super Nailgun
 * Button to open Door below Super Nailgun
 * Room behind gold doorway
 * Right side of platform with Silver Key

Demo
This is the level that the third and final Demo is played. The level is played on Normal difficulty with the default equipment of 25 Shells and a Shotgun. The player collects the Shells and Rockets on the starting platform before looking over the edge to see an Ogre. The player starts firing at the Ogre, though the Monster starts to go under the starting platform after its initial projectiles fail to reach the player's location. The first time the Ogre goes under the platform the player was moving to the opposite side of the starting platform, meaning that the fight continued as normal when the Ogre reemerged from his hiding spot. The player drops to the lower floor as the Ogre goes under the platform once more. He then manages to kill the Ogre, but not without getting hit by a projectile which reduces his Health to 70. The player runs over to collect the Rockets that the Ogre dropped, then heads over to the Floorplate nearby. Pressing the Floorplate opens a Door at the opposite end of a corridor. The player starts walking down the corridor, but the sound of an Ogre is suddenly heard. The player turns left to shoot the Ogre, but instead hits the left wall due to not walking out far enough to see the Ogre. The player continues to look towards the Ogre's location, which is revealed to be beside a Door, as he crosses the corridor. He attempts to fire at the Ogre, but the Ogre has moved to the left side and thus the shot misses it. The player hits the right wall with the Shotgun as he continues strafing down the corridor. As the player reaches a second corridor, another Ogre attacks the player with his chainsaw, lowering the player's Health to 36. The player turns and walks backwards while still facing the Ogre. He then collects the Rocket Launcher and 25 Health at the end of the corridor, bringing his Health back up to 61. The player starts firing at the Ogre with the Rocket Launcher, but gets hit with one of the Ogre's projectiles. With his Health lowered to 35, the player walks into another 25 Health in the same corner, which brings his Health back up to 60. The player kills the Ogre and collects its Rockets, then heads into the next room.

As the player walks into the room, the Door to the right opens to reveal the corridor the player previously avoided with the Door guarded by an Ogre. The player strafes into the Button, which opens the Door behind the Ogre, while looking at the Ogre. The player then starts opening fire on the Ogre with the Rocket Launcher. Strafing left and right between the current and previous rooms, the player kills the Ogre. The player goes through the newly opened Door and crosses the room to collect a Yellow Armor beside a Button. The player hesitates before pushing the Button, turning around to view the Inset Walls on the left and right side. The player turns around once more and pushes the Button, which causes the Movable Wall to the right to lower, revealing an alcove. The player kills the 2 Ogres visible from this alcove, the first normally and the second by Gibbing. The player fires the Rocket Launcher after the Ogres are killed to ensure their deaths. The player looks through the grating in the floor while strafing alongside it to look at the room below while Lavaballs shoot through, then turns to look at a hole in the Floor that was opened up by the Button. The player then drops through the hole to the lower floor, the fall damage lowers his Health to 58.

Upon landing, the player starts firing on an Ogre visible on an alcove straight ahead. The player kills the Ogre and turns to the right to start firing on a second Ogre. The Floor drops to create a staircase to a lower level, blocking the player from seeing the Ogre from his current position. He climbs back up the staircase and jumps near the top to work his way to the Rockets in the corner. The player turns around with the Ogre visible on his right as he continues to back into the corner. One of the Ogre's projectiles land near the player, causing him to lose 9 Health from the Splash Damage. The player then picks up the Rockets and immediately starts firing at the Ogre, which was already injured from a previous shot, with the Rocket Launcher. The shot from the Rocket Launcher kills the Ogre, but the player fires once more to ensure the Ogre's death. The player then descends the staircase and enters the next corridor, turning right to follow it. The player turns around to look at the Large Wall Spike. Turning around once more, the player continues up the corridor. Bars block any progress back, the Large Wall Spike starts moving towards the player, and a Movable Wall opens to the left to reveal an Ogre. The player fires at the Ogre with the Rocket Launcher, killing it while still proceeding up the corridor and turning back to view the Ogre. The first hit with the Rocket Launcher was too close however, causing Splash Damage which further reduces the player's health to 40. As the Ogre dies, Bars to the left can be seen raising. The player continues to back up to reach the 100 Health at the end of the corridor, momentarily increasing his health to 140. The player moves forward to view the Large Wall Spike once more before turning left and going through the doorway opened by the Bars. The player steps onto the Elevator at the end of the small corridor and turns around while it raises. At the top, the player turns left into the next corridor, the alcove with the Ogres that overlooks the area before the Large Wall Spike corridor. The player collects the Rockets dropped by the Ogre and Nails to the left before following the alcove around to the right. The player picks up the Silver Key in the middle section of the alcove. The Demo ends as the message "Your way has been lit" appears on the screen and Bars lower at the far end of the alcove.