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.

Walkthrough

 * Letters in italics refer to marked spots on the map. Sector numbers in boldface are secrets which count toward the end-of-level tally.

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 elevator at the east end of the room, which rises as you step onto it. (The elevator only rises once, so if you fall off the ledge, you cannot get back on.) As you leave the elevator, a trap opens behind you (I), revealing a sergeant (I'm too young to die and Hey, not too rough), or three troopers, two sergeants, and an Imp (Hurt me plenty), or two troopers, a sergeant, an Imp, and a Demon (Ultra-Violence and Nightmare!).

Two openings (J, K), containing barrels and troopers, 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).

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 sergeant and an Imp (HMP), or two sergeants and an Imp (UV and NM).

You can complete the level without the yellow key. Press the switch next to the yellow door, then 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. (If you don't want to risk falling into the pool, you can also retrace your steps through the maze, then walk north from the blue door as far as you can and turn right.) Open the door to the west and take the stairs 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 118)
 * 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 powerups. (sector 71)
 * 3) The alcove at the north end of secret #2 is really an elevator (Q); the switch to the left will cause it to rise.  The soul sphere (sector 88) visible from the green rectangular room is then accessible.  (With great care, it is possible to flip the switch while standing on the elevator.)  The elevator only rises once, so if you miss it, you must walk to the other end of the slime river 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). This seems to prevent the door from opening unless the lift is fully raised.

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).

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).

Demo files

 * [[Media:e1m4secr.lmp|No monsters, 100% secrets walkthrough]] (file info)
 * [[Media:e1m4wk1a.lmp|100% kills, items, and secrets on ITYTD]] (file info)
 * [[Media:e1m4wk2a.lmp|100% kills, items, and secrets on HTNR]] (file info)
 * [[Media:e1m4wk3a.lmp|100% kills, items, and secrets on HMP]] (file info)
 * [[Media:e1m4wk4a.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 e1m4-017 (August 18, 1998), beating Yonatan Donner's e1m4-022. The best time using this trick is e1m4-016 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 used in e1m4-014 (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 sergeant 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 don't 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:

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.

The version of E1M4 in Doom 1.0 contained a swastika-shaped structure (see the map to the right), inserted as homage to Wolfenstein 3D. The symbol was changed to a shape that only loosely resembles a swastika for version 1.4, as John Romero has commented :


 * "Yes, [in Commander Keen 5 ]  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 evil 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 "Rise" by Pantera.