E1M7: Computer Station (Doom)

E1M7: Central Processing is the seventh map of Knee-Deep in the Dead in Doom. It was designed by John Romero and uses the music track "Demons On The Prey". The par time is 3:00.

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
From the start point (A), go through the door and take the first left. Follow the corridor to an alcove on your left (east), the far corner of which contains a lift (B). Go up this lift and follow the ledge around to a small technical room containing the yellow key.

Leave the alcove and bear slightly left (not up the blue staircase). If you play on Ultra-Violence or Nightmare!, watch out for the eight sergeants outside the window to your left (guarding the invisibility), some of whom may open fire as you pass. Go through the yellow door (C) into a computer room. Proceed straight ahead (west), turn the corner, and leave the room through the passage to the south. You will pass a blue door (D), then approach a wide curved staircase (E). As you reach the top of this staircase, the brown column in front of you will lower rapidly, revealing a sergeant (I'm too young to die and Hey, not too rough), or two sergeants (Hurt me plenty), or four sergeants (Ultra-Violence and Nightmare!).

Go around the column and bear right (northwest); follow the passage along through a yellow door and into a large octagonal room containing several barrels and a green armor. At the far end of this room is a lift (F), which leads to a gray passage containing the red key. As you round the turn in this passage, two traps will open elsewhere in the level (G, H), releasing a sergeant and a trooper (ITYTD and HNTR), or a trooper, a sergeant, two Imps, and a Demon (HMP), or a trooper, two sergeants, two Imps, and two Demons (UV and NM).

The red door is near the start point; you would have seen it if you had initially turned right instead of left (I). The blue key is on a balcony behind this door, but as you approach the key, two traps will open elsewhere in the level (J, K), releasing two sergeants and an Imp (ITYTD and HNTR), or four sergeants and two Imps (HMP), or six sergeants and five Imps (UV and NM).

Return to the blue door, and ascend the staircase on the other side. Cross the rectangular room and enter the passage directly ahead. Follow the passage around to a recessed button in a dark room (L), which opens the gray door at the other end of the rectangular room (M). Go through the gray door to the exit room and press the switch.

Other points of interest
As you cross the north side of the computer room, a lift will lower to your left (N). Use this lift to access the central area of the room, which contains a rocket launcher and a shell box.

The column trap near the curved staircase will rise again if you step onto it. By jumping off at the right time, you can land on the small ledge to the northeast (P), which leads to an alcove containing a computer map. (This maneuver is rather difficult, so you may want to save your game first. If the column rises without you, walk to the curved stairway to lower it again.  If you are still on the column when it reaches its maximum height, you are not trapped: the switch on the west wall lowers it again.)  As you pick up the computer map, a tiny bridge rises behind you, connecting the small ledge back to the column area. If you fall into the slime, run to the radiation suit in the back corner (Q), and then see secret #2 below.

If you take the left fork after passing the column, you will go through a door into a dark computer room (O) containing a bullet box and a rocket box. There is also a chainsaw here, though it is not immediately accessible (see secret #1 below).

Secrets

 * 1) If you use the rising column to jump into the nukage pool to the north, or if you fall off the ledge near the computer map, run to the radiation suit in the back corner (Q).  After picking up the suit, turn around and press the red switch behind you.  A small door opens to reveal a staircase (sector 153), at the top of which are a rocket box, two medikits, and a metal switch.  Pressing this switch opens the square column with the chainsaw inside (R).  To get out of the nukage, see secret #2 below.
 * 2) The north nukage pool must be exited by running to the extreme northern end, where there is a small platform (S) with a soul sphere.  As you step onto this platform (sector 71), a hidden door opens to your right, providing a shortcut back to the beginning of the level.  On your way through the nukage, you will also see a tall brown column on your right; concealed here is a small alcove (T) containing blue armor.
 * 3) If you instead jump from the rising column into the south nukage pool, you will find a thin concrete platform (U) containing a chaingun, several large ammo pickups, and a medikit (sector 147).  This platform also adjoins a narrow passage leading to a backpack.  As you reach the backpack, a hidden door opens to your left, returning you to the curved staircase.  Note that this nukage pool contains one armor bonus (V).
 * 4) One of the traps triggered by the blue key platform (K) contains a secret door on its east wall, indicated by a greenish texture.  This reveals a passageway (sector 94) leading to the large courtyard with the invisibility (W).

Bugs
Four barrels (Things 112, 113, 114, and 187) have no flags set for any of the three difficulty classes, so they do not actually appear in the level.

Linedef 450 has its upper texture on the wrong side, resulting in a Hall of Mirrors effect. This is not normally observed, however, because the corresponding sector (a tiny hidden area of height 8 near the rocket launcher) is inaccessible without cheating. Similarly, linedefs 744, 745, 746, and 747 have their upper textures on the wrong side, but the HOM is visible only from the chainsaw platform before its walls have been lowered.

One end of the chaingun can clearly be seen through the low wall which obscures its platform (from the left edge of the curved staircase, or from the right side of the bridge if approaching from the chainsaw area).

The following actions can trigger the blockmap bug:


 * From the extreme western edge of the first room, firing into the central area (not along the blue gallery).
 * Firing along the blue gallery at a slight angle.
 * Attacking a Demon in the first section of the red key corridor.
 * Firing westward in the northern part of the large octagonal room.

Slime trails may be visible in the following locations (see screen shots below):


 * Just past the first door, looking toward the yellow key alcove.
 * Outside the red door, looking southeast.
 * At the T-intersection on the western edge of the first room, looking east.
 * Looking along the blue gallery from the west end.
 * Looking at the northern slime pool through the window in the first room.

Demo files

 * [[Media:e1m7secr.lmp|No monsters, 100% secrets walkthrough]] (file info)
 * [[Media:e1m7wik1.lmp|100% kills, items, and secrets on ITYTD]] (file info)
 * [[Media:e1m7wik2.lmp|100% kills, items, and secrets on HTNR]] (file info)
 * [[Media:e1m7wik3.lmp|100% kills, items, and secrets on HMP]] (file info)
 * [[Media:e1m7wik4.lmp|100% kills, items, and secrets on UV]] (file info)

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

Inspiration and development
Early versions of this level appeared as E1M4 of Doom 0.4 and E1M4 of Doom 0.5.