E1M4: Command Control (Doom)

E1M4: Command Control is the fourth map of Knee-Deep in the Dead in Doom. It was designed by Tom Hall and John Romero, and uses the music track "Kitchen Ace (And Taking Names)". The par time is 1:30.

Essentials
You begin in a short corridor (A), facing a door. Behind the door is a green rectangular room with three corridors leaving it to the west. Take the center corridor, and run to the lift that lowers as you enter the next room (B). At the top of the lift, turn right and enter a large round room. The structure in the center, which opens as you approach it, contains the blue key (C) and a chaingun. (If the doors should happen to close while you are inside, walk again over the small lighter-colored square where the key was). After picking up the blue key, leave the round room to the west, turn left, and look for a blue door ahead of you to the right (D). Behind the blue door is a gray maze. To get through the maze quickly, take the first right and bear slightly left to go down a long corridor heading north. At the end of the long corridor, turn right, then immediately left, and then left again. (You will notice the wall texture changes in the hallway ahead.) The passage widens into a room containing a green armor and the yellow key. Get the yellow key (E), then go up the staircase to the north, which leads to a yellow door (F). Click the switch next to the door (this raises the bridge leading to the exit door), then go through it. Turn right and cross to the gray door, but when you reach the door, turn around, and you will see the exit door up the stairs to the west (G). Go through the exit door and press the switch.

Other points of interest
If you leave the green rectangular room through the right-hand corridor, you will come to a room with a wide ledge containing a blue armor (H). Get to the ledge using the brown lift at the east end of the room, which rises as you step onto it. (That lift only rises once, so if you fall off the ledge, you cannot get back on.) As you step on the blue floor, a trap opens behind you (I), revealing a shotgun guy (I'm too young to die and Hey, not too rough), or three zombiemen, two shotgun guys, and an imp (Hurt me plenty), or two zombiemen, a shotgun guy, an imp, and a demon (Ultra-Violence and Nightmare!).

Two openings (J, K), containing barrels and zombiemen, overlook the green rectangular room (in between the three corridors on the west side). These are accessible by leaving the large round room to the north and to the southeast.

After your first right turn in the maze, if you bear slightly right instead of slightly left, you will enter a zig-zag corridor containing a box of bullets (L), guarded by a demon (HMP and lower) or three demons (UV and NM).

To the east of the exit staircase is a computer room with a blue floor (M). This room contains two boxes of rockets, but as you walk around the perimeter, you may trigger a trap (S) which slides the computers into the floor, revealing a shotgun guy and an imp (HMP), or two shotgun guys and an imp (UV and NM).

You can complete the level without the yellow key. Press the switch next to the yellow door, then retrace your steps through the maze, head north from the blue door as far as you can, and turn right into the blue computer room. Or, to take a shortcut (albeit one with the added risk of falling into a slime pool), walk through the window just east of the yellow key. A very narrow ledge runs along the wall to the right, above the nukage pool, which allows you to reach the stairs on the south side (N) without taking any damage. Go up the stairs, then leave this room to the east and follow the short passage into the blue computer room. Once in the blue computer room, open the west door and ascend to the exit.

Secrets

 * 1) In the short corridor where the player starts, there is a secret door on the south wall. It reveals a small room (O) containing a backpack, a medikit, and a box of shells. (sector 75)
 * 2) From the green rectangular room, leave through the left-hand corridor. This leads to a room containing a slime "river". Drop down into the slime river and go east. You will reach a room (P) containing a rocket launcher and various other supplies. (sector 99)
 * 3) The alcove at the north end of secret #2 is really a lift (Q); the switch to the left will cause it to rise. The soul sphere (sector 102) visible from the green rectangular room is then accessible (with great care, it is possible to flip the switch while standing on the lift). The lift only rises once, so if you miss it, you cannot get the supercharge nor the secret sector. To escape the slime river and return to the rest of the map, you must now run to the other end and take the lift out (R).

Bugs
Sector 41 (the yellow door) is incorrectly assigned tag number 3, which is used for the square lift just east of the large central room (B). If the lift is in use, the door cannot be opened and vice versa because Doom only allows a sector to undergo one movement type at a time. Due to the distance and maze between the door and the lift, however, this bug is unlikely to affect normal play unless it is a multiplayer session or you have left many monsters alive in the early areas. (Boom and many subsequent ports have removed this limit and allow a sector to perform multiple movements simultaneously.)

Linedefs 608 and 609 have orphaned tags.

Sidedefs 345, 353, 369, and 379 are missing their lower textures, and sidedef 872 is missing its upper texture. Each of these results in a small Hall of mirrors effect (see demo below).

Two shell pickups (Things 16 and 48) have no flags set for any of the three difficulty classes, so they do not actually appear in the level.

Sectors 9, 105, 132 and 137 that make up the door frames of the inside of the blue key room are recessed into the floor 8 units. However, they lack lower textures on the door sides leading to some bleeding when viewed from inside the room.

The blockmap bug can occur in the long central corridor of the maze.

Examining tangentially the small nukage pools near the blue key chamber may reveal several slime trails (see screen shots below).

There are 21 known anomalies in this level's REJECT table.

The first bug was fixed in the Nintendo Switch port of Doom. That is, the tag of sector 41 was zeroed.

Demo files

 * [[Media:e1m4secr.lmp|No monsters, 100% secrets walkthrough]] (file info)
 * [[Media:e1m4wik1.lmp|100% kills, items, and secrets on ITYTD]] (file info)
 * [[Media:e1m4wik2.lmp|100% kills, items, and secrets on HNTR]] (file info)
 * [[Media:e1m4wik3.lmp|100% kills, items, and secrets on HMP]] (file info)
 * [[Media:e1m4wik4.lmp|100% kills, items, and secrets on UV]] (file info)
 * [[Media:e1m4linz.lmp|Five small HOMs due to missing textures]] (file info)

Ledge run
It is possible to jump across the nukage pool from the east side (onto the narrow ledge). This allows one to go directly to the yellow key, bypassing the blue key and the maze.

The story behind the discovery of this trick is given by Compet-n:


 * The first player to discover the trick was Steffen Winterfeldt, who sent his demo to Yonatan, but for some reason this was not included in COMPET-N. Later, Jonas "Chrozoron" Feragen independently discovered the trick. As he was never a COMPET-N player, he sent his demo to Yonatan, who did not upload this either. Later, Rudy Jurjako also discovered the same trick. He somehow sensed the truth in his text file: "I have a hard time believing that I was the first to discover that jump...". Just one day later, Ralf Schreivogel also discovered the jump, not knowing of Rudy and the other people.

Rudy Jurjako's demo was 0:17 in length (August 18, 1998), beating Yonatan Donner's 0:22. The best time using this trick is 0:16 by Adam Hegyi (August 25, 1998).

Romero has confirmed in a reply to Adam Williamson that the trick was inserted deliberately:


 * Here's the answer, straight from The Man who mainly designed E1M4, Tom Hall: "Heeeeeeeeeee. Yeah, I'm pretty sure. :) But not sure if you can get to it.... it stops before it gets to the stairs now...so I think you'd have to get propelled backward somehow... so long ago though...


 * I totally forgot that this was in episode 1...man, I should play it again...yeah, like I have time..."


 * So... i think he *did* design it for a shortcut.


 * John Romero

Exit jump
Using strafe 50, it is possible to jump across the 192-unit gap in the exit room, completing the level without any keys at all. This trick was created by Adam Hegyi and first submitted on June 8, 1999. The time was subsequently refined to 0:13 by Jonathan Rimmer, and ultimately to 0:12, believed to be optimal, by Hegyi. However, Andrey "entryway" Budko reached 0:11 in his tool-assisted run of the episode, using strafe 50 throughout the entire map.

Because a tiny error in the player's angle can cause the jump to fail (the maximum possible distance of such a jump is 194 units), it is considered too risky to use in an episode run.

The gap can also be crossed without strafe 50, by rocket jumping. Due to the detour involved in grabbing the rocket launcher (and the soul sphere, in order to survive the blast), this only saves time in the NM100S style.

Other tactics
If none of the above tricks is used to bypass the blue key, the time of a straight speedrun is largely determined by how well you dodge monsters in the maze, especially as you enter the yellow key room.

By opening the yellow door before pressing the switch, you can run onto the exit bridge from the side as it rises.

UV max and UV -fast runs generally use this route: Anders Johnsen credits Peo Sjöblom with inventing the route. The use of rockets is remarkably consistent from one Compet-n entry to the next: two in the green rectangular room (to kill the two demons), two or three in the blue computer room, and the rest in the maze. In an episode run, the very first step is of course redundant, but is usually done anyway to draw a crowd of monsters to the south end of the green rectangular room (for more infighting and more efficient use of blast damage).
 * Get the shotgun from the shotgun guy in the blue armor room immediately, then go to the soul sphere.
 * Open the blue armor trap, get the blue key, then clear the blue computer room.
 * Clear the maze by killing the two southernmost imps, firing a shot in the long central corridor to wake up most of the other monsters, then firing rockets northward up the central corridor. (This is extremely dangerous in -fast mode, because of the demons' doubled speed.)

The efficient use of barrel frags can greatly reduce the time of such a run. (Therefore, clear the blue computer room from the south side.) Some luck is also required, since stray monsters can easily be left behind in the two passages overlooking the green rectangular room.

It is possible to jump over the slime river by straferunning. This saves a small amount of time in runs requiring 100% kills, by making it easier to avoid exploding barrels on the way to the rocket launcher.

In NM100S, the shortest route from the soul sphere to the large round room is to jump down into the green rectangular room, then immediately turn left. For episode runs, many players instead use the slime river to conserve health.

Due to the linearity of the map (only the green rectangular room needs to be entered twice), UV -respawn differs from UV max only when the player must pause briefly to fight a crowd, as with the entrance to the yellow key room. A truly optimized run might kill a few people twice in the green rectangular room and the yellow key area, then skip the blue computer room; or kill a few people twice in the green rectangular room and the blue computer room, and ignore monsters who do not enter the central corridor of the maze right away.

UV Tyson runs are somewhat faster when there is a lot of infighting in the green rectangular room (including monsters from the blue armor room) and near the blue door.

UV pacifist runs tend to use the same routes as UV speed runs.

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

The data was last verified in its entirety on December 2, 2014.

Player spawns
This level contains nine spawn points:
 * 1) facing east. (thing 184)
 * 2) facing east. (thing 185)
 * 3) facing east. (thing 186)
 * 4) facing east. (thing 187)
 * 5) facing north. (thing 188)
 * 6) facing north. (thing 189)
 * 7) facing north. (thing 190)
 * 8) facing west. (thing 191)
 * 9) facing east. (thing 192)

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

Inspiration and development


E1M4 was started by Tom Hall and finished by John Romero. Primitive versions appeared as E1M7 of Doom 0.4 and E1M7 of Doom 0.5. It may have been based on the "Enlisted Quarters" in episode one of the Doom Bible, as the Doom 0.4 version contains locker rooms and showers.

The version of E1M4 in Doom 1.0 contained an inverted -shaped structure (see the map to the right), in homage to Wolfenstein 3D. It was later changed to a traditionally oriented swastika in version 1.2. The symbol was changed again in version 1.4, this time to a shape that only loosely resembles a swastika, shifting the vertical connectors horizontally outward. The Atari Jaguar port of Doom, based on version 1.2, instead chose to delete the vertical appendages altogether.

In regards to this, John Romero has commented :


 * "Yes, [in ]  there is a swastika in one of the levels, one of my levels to be exact, but I removed it shortly after the game was released because people were upset that an  symbol was in a cute kid's game (the changed version is in the screenshot). It was a premonition of things to come, namely, Wolfenstein 3D. I also put a swastika in Doom ' s E1M4 as a Wolf3D reference, but I changed it later for the exact same reason."

Trivia
The music for this level is inspired by the track "" by.

The first Doom novel references the swastika-shaped structure, when Fly discovers "several -9000" computers had been placed together to create "a freakin' swastika". He was unsure whether it was created by the alien invaders as a scare tactic or as a joke by certain UAC workers.