MAP22: Impossible Mission (The Plutonia Experiment)

MAP22: Impossible Mission is the twenty-second map of Plutonia. It was designed by Dario Casali and uses the music track "The Dave D. Taylor Blues" from Doom II (the same as Doom II's MAP22: The Catacombs).

Essentials
Blue key

You start on a raised platform. Walk forward to activate a lift and lower onto the floor of the room. Exit the room and go up the western flight of stairs. You will come to a room with a slime-filled corridor and a slime waterfall ahead. Hug the right wall of the room to enter a passageway, and follow it into a large room full of slime. The entrance is blocked by a large number of chaingunners and barrels - carefully use the rocket launcher to take them out with one shot. Enter the room, being wary of a Hell knight ambush (on Hurt me plenty and higher).

Proceed to the southwest of the room to find the blue key in an alcove. This alcove is a drop trap - when you step on it, the floor lowers into a room with three demons (on Hurt me plenty and below), or three shotgun guys (Ultra-Violence and above). Dispose of them, and enter the teleporter ahead.

You will be teleported to the top of the slime waterfall you saw earlier. Walk forward and drop back down to the room at the top of the staircase.

Yellow key

Go down the staircase, and immediately turn left. You will now enter a maze-like area infested with chaingunners. Turn left at the first fork to come to another fork. Look in both directions, and notice walls with scrolling spine textures. Remember their positions - they are traps that will be opened later.

Turn right (north) at the fork, and follow the path around, being mindful of two "bunkers" with enemies along the way. When the path forks again, follow the left path to a switch and flip it. Retrace your steps to the fork, and continue west.

You will arrive in a room with some burning barrels, a switch blocked by yellow bars and a teleporter, out of reach. Kill the imps in this room, and find a small platform in the west wall. Ride the platform down, and prepare for a chaingunner ambush from both sides.

You now enter into a large outdoor area, filled with (non-damaging) slime and numerous enemies, with a raised path to the yellow key. As you follow the path, the center part sinks to the floor. Head to an opening in the northwest of the area, clear the enemies on the stairs and follow the path to its end. Use the metal block to step up to the grassy platform where an arachnotron is/was, and flip the switch. This raises the center part of the path back to its original height. Walk back down to the slime pool, and notice a new switch near the northern teleporter. Do not use the switch yet - take the teleport first to be teleported back to the beginning of the raised path. Follow it to the yellow key, then drop in the northern half of the slime pool. Flip the switch, enter the teleporter, and step onto the re-lowered lift.

Backtrack to the blue doors south of the starting room, being wary of three traps:
 * The walls with scrolling spine textures are now fake walls with chaingunners behind them.
 * A revenant has been released into the maze.
 * Two barons of Hell have been released near the start room.

Red key

Go through the blue door to enter a large slime room. Head for the south of the room, defeat the arachnotron, and head west. Follow either path around to an outdoor area with chaingunners. Flip the switch in the east of the outdoor area, which will unlock a path in the northeast of the slime room.

Backtrack to the slime room. The "slime pipes" will have opened up to reveal mancubi. Defeat them, then proceed to the northeast of the slime room, where the passage has been unblocked. Follow the passage to its end, where there is a slime-walled room with four spectres. Flip the switch in the southeast corner to open a door in the northwest, head to that door and ride the lift up.

You should be now on the yellow switch platform. Flip the switch.

Return to the open air area after the maze, with the switch and teleporter. The yellow bars blocking the switch will have raised up. Flip the switch to lower the teleporter to the ground. Equip a powerful weapon, preferably the BFG9000, and go through the teleporter.

You will be on the red key platform. Enemies will rise up from the ground, including an arch-vile (on Hurt me plenty and above). Grab the nearby soulsphere (Ultra-Violence and above, otherwise a megasphere) and get off the platform if needed. Prioritise the arch-vile to prevent resurrections, and then systematically remove the remaining barons of Hell.

If you got off the platform, you will need to go through the previously mentioned teleporter to get back onto the platform. Grab the red key.

Exit

Exit the large slime room through the eastern blue door, and enter the red door ahead. Proceed to the northwest of this open area, where there is a platform with a switch. Get on the platform via the stairs and flip the switch on the west side of the block. This will unblock the path leading to the exit.

Leave through the same red door that you came in, and then turn left into a tan room leading to an L-shaped bridge. Follow the bridge, open the yellow door at its end and follow the cave to the exit teleporter to end the level.

Secrets

 * 1) Behind the blue doors is a huge nukage pool. At the south of this area is a tunnel, at the start of which you can see a rocket launcher behind a gate. Continue along the tunnel to the right, hugging the left wall as you go. One of the walls lacks the green glow along its bottom edge that the surrounding walls have. It can be opened, and the passage behind it leads to the aforementioned rocket launcher. (sector 85)
 * 2) In the narrow passage leading to the rocket launcher in secret #1, there is another wall that does not have a green glow on it. Open it to reveal a teleporter to a ledge back in the nukage pool area. (sector 84)
 * 3) Still in the nukage pool area, step onto the platform bordering the eastern of the two blue doors. Quickly open the door and hug the left wall. An alcove containing a teleporter to a secret area will be open temporarily (Note: Crossing from the nukage onto the platform or vice versa is what actually triggers the alcove to open). (sector 50)
 * 4) Behind the red doors is a wooden structure with a switch on it, at the far side of a lake of nukage. While the "front" (west-facing) side of the switch opens the door to the exit, the "back" (east-facing) side opens a secret room in the nearby cave with the glowing red floor. (sector 130)

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 eight spawn points:
 * 1) facing south. (thing 437)
 * 2) facing north. (thing 438)
 * 3) facing east. (thing 439)
 * 4) facing east. (thing 440)
 * 5) facing west. (thing 441)
 * 6) facing north. (thing 442)
 * 7) facing south. (thing 443)
 * 8) facing west. (thing 444)

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