E1M9: Omgekeerd (Heretic Treasure Chest)

E1M9: Omgekeerd is the ninth and secret map of episode 1 of Heretic Treasure Chest. It was designed by Lord Z and uses the music track "Sacred Grove" from Hexen, created by Kevin Schilder.

Essentials
Open the door and drop to the sky-floor below, where a number of fire gargoyles are guarding a Dragon Claw, Quartz Flasks and ammo. Go through the opening in the south wall to enter a tunnel with nitrogolems, which you can follow to another sky area with more nitrogolems as well as fire gargoyles and disciples of D'Sparil (the tunnel will seal behind you as you exit it). Climb up the lava steps by the west wall to reach an Ethereal Crossbow, then open the door behind it and climb the staircase past some golems to another door with one or two undead warrior ghosts behind it. Open the brown door on your left and head down another staircase guarded by nitrogolems - at the bottom is a water pool with undead warriors guarding a switch.

Press the switch and head back up the stairs, passing alcoves containing (depending on skill level) golem, nitrogolem or undead warrior ghosts, until you return to the brown door at the top. Go through it and head north through another now-open door to a room with golem and nitrogolem ghosts guarding the blue key, then continue north through a gold door to find disciples guarding a switch which will lower the key so you can collect it. Kill the disciples which have been released into the blue key room, then return to the large sky area and open the gold bars in the east wall - behind these bars is a teleporter that will transport you to an "upside-down" version of the same level.

Open the bars and head west towards the door you used earlier to find the blue key - just before you reach the door, enter a small enclosed area on your right to find a Bag of Holding next to a switch which will open the blocked ice tunnel to the north. Enter that tunnel and follow it past some nitrogolems to a circular dirt area guarded by golems and nitrogolems. Collect all the items in this area then open the north door to find a disciple (and undead warrior ghosts on medium and hard skill levels) guarding the exit teleporter.

Secrets

 * 1) Lower the wall behind your starting point to find a Mystic Urn. (sector 32)
 * 2) In the staircase at the south-west end of the first area, flip the switch at the bottom and watch the walls around you lower. When they lower all the way, you will find an alcove containing Gauntlets of the Necromancer. (sector 158)
 * 3) In the blue key room, press on the wall east of the south-east column to drop down to a Morph Ovum. (sector 211)
 * 4) Open the blue bars, but do not enter the teleporter yet. Press on the wall to the south and the next wall to find a Shadowsphere. (sector 96)
 * 5) Enter the teleporter mentioned in secret #4 to reach the second half of the map, then open the wall to the south, similar to what you did for secret #4. This time you will find a Chaos Device. (sector 418)
 * 6) In the second area, go all the way to the door at the west end and use it. The door will not open, but a part of the wall to the north lowers instead. Quickly go over it and to the left, where the Enchanted Shield is. The wall should rise up, allowing you to get the item. (sector 462)
 * 7) In the last arena, the column in the middle has a switch on its west side. Press it, then run straight west through the vines to find a Phoenix Rod. (sector 471)

Bugs
When you press the switch to lower the blue key, you will also allow enemies in a teleport closet to teleport into the level, landing on the pad in the middle of the southern part of the first area. However, the landing destination is only flagged for thou art a smite-meister or black plague possesses thee skill levels, meaning two golems and up to eight gargoyles will not teleport into the map on lower difficulties.

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

The (absence of) data was last verified in its entirety on January 16, 2022.

Player spawns
This level contains four spawn points, all of which are located in the second half of the level:
 * 1) facing north. (thing 298)
 * 2) facing east. (thing 300)
 * 3) facing west. (thing 301)
 * 4) facing east. (thing 302)

Weapons spawns
The following weapons only appear in multiplayer:
 * A Dragon Claw on an island in the lava in the south-west corner of the second area. (thing 292)
 * An Ethereal Crossbow in the ice tunnel in the second area. (thing 293)
 * A Firemace in secret #6. (thing 294)
 * An Ethereal Crossbow in front of the door to the exit teleporter. (thing 296)
 * A Dragon Claw by the central column in the arena before the exit teleporter. (thing 297)

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

Trivia

 * Omgekeerd is the Dutch word for reversed, hinting at the path the player can expect in the second half of the level.