E3M6: The Halls of Fear (Heretic)

E3M6: The Halls of Fear is the sixth level in The Dome of D'Sparil episode of Heretic. It is the first level in the game to have a non-boss maulotaur in an area that is essential for the level's completion.

Yellow key
Enter the hallway to the north, but drop down to the water below. Look for a cave on the south of the eastern wall, and reach the yellow key at the end of the tunnel.

When you reach the yellow key, the wall ahead of you will lower to reveal an iron lich. You can evade it or fight it at your preference, although there is a Dragon Claw at the back of the revealed room.

Return to the starting area - the easiest route is through the teleporter at the north end of the water.

Green key
From the starting area, run north, and turn west through the yellow key gate. This opens to a large corridor filled with weredragons and sabreclaws hiding in the alcove - they will only approach if they can see you. When you are ready to cross the corridor, head to the left, and press the south switch to open the west and east doors (as well as the sub-corridors to the north and south). The north switch adjusts the starting area, making it easier to reach a secret below.

Enter the west corridor, and proceed to the southern end. Find the switch on the north wall and press it. Return to the north end of the corridor, and press the revealed switch in the northwest corner. Return to the starting corridor, and the green key should be to the north and reachable. (If the door back is closed, you can press the switch to the south, or use the teleporter in the middle of the west corridor.)

Blue key

 * Caution: A maulotaur is somewhere behind the green key door. Make sure you have room to retreat if he is at the door.

In the middle of the west corridor, open the green key door on the right. You first need to unblock the stair by pressing the switch at the north of the watery area. Next, climb the stairs to the south to retrieve the blue key. When you reach the blue key, the water level will lower - if you fall in, you can escape using the teleporter behind the iron liches.

You can return to the starting area by heading east from the blue key. Turning north (as opposed to jumping back into the water) will open the rest of the map, so that you can explore.

Map exit
The exit is behind the blue key door, at the south of the western corridor. Follow the blue-colored rooms.

Note that entering here will create another pathway to the main level, which leads to an area tagged as a secret.

Official

 * 1) When you have entered the yellow door, you will find yourself in a gloomy hallway with many alcoves. At the western end, there are two switches. You need to press the southern one to open the second main door, but the switch will also open the back walls of some of the alcoves. Enter the exposed room in the north to get a Silver Shield along with health and ammunition items.
 * 2) A room in the south has been revealed similarly. The place holds a Mystic Urn, a varying amount of Quartz Flasks and some ammunition.
 * 3) The northern switch will raise the starting area so that you can step onto the barrier there and run over a gap to a new zone. A Phoenix Rod and an Enchanted Shield can be found there. North of the weapon is a passage that can be used to get to a Tome of Power and back to the start. However, a floor will lower in the west while you proceed. It will reveal a shortcut staircase to secret 2, but when you enter the familiar area again and face to the east, you will notice that an alcove with a Bag of Holding has become accessible. The place counts as a secret.
 * 4) When you have the bag, return to the bottom of the aforementioned staircase and go to the Phoenix Rod's location. The doorways around it can now be entered, and you can get a Map Scroll.
 * 5) Another staircase can be accessed near the scroll. Enter the stairs, and when you arrive at the long flat section at the bottom, face to the north and press the wall to lower it as a lift. On the top, there is a room with many timebombs, a new Bag of Holding and some nitrogolems.
 * 6) Proceed to the eastern end of the staircase and press the back wall to open it. Another door will open behind it revealing a varying amount of ophidians, a Pile of Mace Spheres, a second Mystic Urn and yet a third Bag of Holding.
 * 7) At the blue door, you will find two banners. Go through the false wall between them to find a room with two ophidians. They were placed there to fire through a false window. In addition, the area contains some Mace Spheres, a Morph Ovum, an Inferno Orb and Greater Runes.
 * 8) When you enter the water of the maulotaur yard behind the green door, four wall pillars will open. Two of them are located at the northern staircase on the other side of the green door. These pillars have revealed a chamber with a Shadowsphere.
 * 9) The remaining two pillars have given access to another chamber at the southern staircase. The area holds a Tome of Power. Note that both secret chambers also have disciples and Mace Spheres in them.
 * 10) When you are about to take the blue key, the water level of the maulotaur yard will go down, and a sheltered area will be exposed at the bottom. There are the Wings of Wrath, ammunition for the Hellstaff and a varying amount of iron liches. Use the wings or the teleporter to return up.

Non-official

 * 1) The water area that surrounds the starting position has a secret door at the northern end of its western side. The door has been marked with a Quiver of Ethereal Arrows, and it hides a teleporter and a Ring of Invincibility. Use the teleporter to reach the ledge on the eastern side. Collect the Hellstaff and the ammunition.

Firemace
If the Firemace has appeared, you can have it at one of six different locations. It is the last chance to obtain the weapon in the episode. In order of appearance, the places are:
 * Water near the door of the sole non-official secret
 * Secret 3 (with the Bag of Holding)
 * Secret 5
 * Secret 8
 * Secret 9
 * Secret 10

Bugs

 * In order to pick up all items, the player has to use the no clipping cheat to obtain a Quartz Flask. It is placed in the void 128 map units south of the eastern yellow door.
 * Linedefs 343 and 370 lack upper textures near the yellow key and secret 6. The error causes distorted views on both sides of the downward moving door.
 * North of the previous door, a decorative wall torch (thing 448) near the crossbow has not been flagged to appear on the two highest difficulty levels. On either of them, the lighting of the adjacent sector seems to oscillate on its own which suggests that the arrangement was an oversight.
 * In deathmatch, it is possible for a player spawning within the green key area (at thing 462) to be trapped in the room until he is killed or another player lets him free by entering the room. This is caused by moving across linedefs 924 or 925 (the last step to the upper platform) before reaching the switch to the north, along with the north switch being unreachable after the water lowers.

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