MAP20: The Death Domain (The Plutonia Experiment)

MAP20: The Death Domain is the twentieth map of The Plutonia Experiment. It was designed by Dario Casali and uses the music track "Message For The Arch-Vile" from Doom II (the same as Doom II's MAP20: Gotcha!).

This level was also ported to PlayStation Final Doom as MAP29: The Death Domain.

Essentials
Yellow key

You start in the large outside area infested by arachnotrons. Revenants also hide in the cages at the tops. If this is your pistol start, turn right and walk around the grey brick tower to find a plasma gun (or a chaingunner on higher skill levels whose chaingun you can obtain). After all, head northwestward in this place. You can see two shotgun shells and a small dead end closet. Flip the switch to build the stairs leading down. Descend down into sewers. Head north and get super shotgun. After that, head east and at the end, turn left to see a lift. This is activated via pressing the switch right here. Using the lift, travel to the highest story. Kill the demons and press the dark blue skull switch. This will open the door in the middle story, so travel there.

You are now in a library. The walls will lower when you approach the east of the library revealing some Hell knights and an arch-vile. The door to proceed further is located in the east of the library but is locked. To unlock, face west and press a bar-like button located near the entrance. After this, be quick and run to the door.

In the next room, you can see a blur artifact in the middle of the room which is behind the fence. Actually, it acts as both a bait and your main objective for completion. Walk into the barrier and take the sphere. Chaingunners (and shotgun guys depending on skill level) surrounding the room will be lifted up. Because you are invisible now, this will make it tough for them to injure you but hurry to eliminate them all. Enter the next door in this room. In the dark room, ascend the stairs up. In the marble room, go southward. Turn left in the corridor and right. You should go past the yellow keycard. You may take it, but this is optional (but very recommended; this will be explained later).

Blue key

Take the lift and enter the western arena. If you face east you notice two alcoves from which barons of Hell should come out. Be careful, as once they enter the arena they will have the ability to teleport to random points in the arena. Once you dispatch them, enter the second alcove (southern one) in which one of them was. Flip the switch. It will temporarily lower a barrier between fence (north of the arena). When the barrier is lowered, you should make a good jump from here into the nearest fenced pool.

In case if you have successfully managed to drop into the pool, take the blue skull key. Immediately, you will be teleported into another similar pool which unlike the previous one has nothing to collect. Go around here, to teleport again. You will be teleported right on the berserk pack standing near the blue door.

In case if you failed to drop, make another attempt to do. If you have the yellow key, open the yellow door in the starting area. This will lead you back to the arena. Unfortunately, if you got no yellow key, you need to make the very long path back to the key, like the one you did when going for the first time.

Exit

With the blue key collected, open the blue door north in the starting area. Ascend the stairs up into the marble room. Turn right to the balcony where the chaingunners were and use the exit portal.

Official

 * 1) Once you reach the switch-activated lift in the "sewer" area, rather than riding it up, walk through it to the other side. Here, along with a security armor and rocket launcher, there is a baron-faced wall. Press the use key on it as you would do on a door or a switch. Although you will not be able to hear anything, it opens the locked door near the stairway you lowered to enter the sewer area. Behind it is a pathway leading to an ammo cache and a combat armor vest. (sector 104)
 * 2) In the "library" area in the north is a wall with two red flags on it. To open it, press the use key on the lights to either side of it. Behind it is a lift to a soul sphere. (sector 137)

Non-official

 * 1) As soon as you enter the marble room right near the exit portal with the floating eye surrounded by a green symbol (see the second screenshot), turn to your left (north) and you will see a narrow door. Shoot it to open a small room containing a megasphere.
 * 2) In that same room there will be a hallway with a medikit at the end. As soon as you get to the end of the hallway, run back and make a right. A platform will have lowered revealing a hallway with a backpack along with several rockets and clips.

Bugs
Linedefs 179, 194 and 202 (three of four sides of sector 21, at the bottom of the staircase in the starting area) have action "S1 Floor Lower to Lowest Floor" assigned to them; although this step is sunk into the floor, it is still possible to trigger the lines by pressing use on them. Doing so pushes all the stairs down by one stair height, making it impossible to climb back up to the starting area.

Current records
The Compet-n records for the map are:

The data was last verified in its entirety on July 6, 2020.

Player spawns
This level contains nine spawn points:
 * 1) facing east. (thing 22)
 * 2) facing east. (thing 25)
 * 3) facing south. (thing 76)
 * 4) facing north. (thing 77)
 * 5) facing south. (thing 83)
 * 6) facing north. (thing 84)
 * 7) facing north. (thing 85)
 * 8) facing south. (thing 86)
 * 9) facing west. (thing 87)

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