This is an extract from Section 10 of the Doom FAQ v6.666 by Hank Leukart.

CHAPTER [10]: Can someone tell me how to...?

        This chapter is full of spoilers for people who are "stuck" in the
game.  Enjoy!

[10-1]: Where are the DOOM secret levels?

[10-1-1]: Knee-Deep in the Dead
        You must be on level three to access the secret level in DOOM.
First, there is a room with an elevator with armor on it in the northwest
corner of the map.  Press the red button in this room. This opens a corridor
in the room where you can see a glowing sphere.  The room it leads to has
some lighted alcoves.  Walk up the stairs.  You should be able to hear a
mechanical sound.  This is the sound of two alcoves being lowered.  The map
looks similar to this drawing.  (I love the beauty of ASCII art)

                        Alcove 1 /\ /\
                                 \/    \
                                /   /\   \
                              /     /  \   \
                            /   /\/      \   \
                            \   \        /   /
                            /\   \    /    /
                            \/ \   \/      \
                        Alcove 2 \     /\    \
                                   \/     \    \
                                            \    \
                                              \ x

        Walking into this room normally, the alcoves rise before you can see
them.  But, if you run up the stairs to one of the alcoves fast enough,
you can get in it and rise to a secret door.  Alcove 2 leads to the
blue glowing sphere.  Alcove 1 leads to an island surrounded by ooze.
You can get a rocket launcher here.  In alcove 1, follow the ooze down
the tunnel.  The tunnel leads to a switch that raises the bridge over the
opening ooze pit.  A secret door is also near the switch, but the bridge
leads to the secret exit.  REMEMBER TO >BOOK< TO THE ALCOVE! :)

[10-1-2]: The Shores of Hell
        When you get to Command Center, walk out the elevator door, and
turn right.  Walk up the stairs in the far right corner.  At their top of
the stairs, enter the door to the right.  Walk to the end of the hallway.
Open the door, and look to the right.  Open that door and turn the switch
immediately on the right in that room.  That switch raises stairs in the hall
you just left.  Walk up those stairs, get through the red curtain, and get on
the transporter.  Kill the lost souls in the room you are transported to
and open the hidden door there (a lion head marks it).  Again use the
transporter, and you will find yourself walking towards a marked EXIT-door.
Enter and turn the switch!

(10-1-3): Inferno
        The process of getting to the Inferno secret level is probably one of
the most creative things in DOOM, and the most difficult to figure out.  The
way to get there is from level 6, "Mt. Erebus".  You must get inside a blue
box with no ceiling which is in a large triangular depressed area with
"water" at its bottom.  Inside it is a skull switch ending the level. Getting
inside the box counts as one of the secret passage units for the level.  Next
to the box is a large red building which one can get on top of.  To get on
top of it, you must use the secret teleporter in the building with the
berserk pack and stairs in it, with the four Imp cages by the entrance.  For
specifics, the teleporter leading to the ledge above the blue box is located
at <0x27ed486,0x2315201>.  Upon entering the building, you will see a secret
opening to the teleporter on the left.  The teleporter takes you to a ledge
on the top of the red building.  If you go to the right along the ledge you
will be looking down at the blue box.  Unfortunately, the distance is too far
to jump.  The key is to shoot a rocket at the ledge wall, the explosion of
which will throw you into the box!  The area on the ledge where you want to
fire the rocket at the wall is located at <0x375bead,0xa900072>.  There is a
rocket launcher on the level, on a platform out in the open with a chaingun
and a bunch of monsters.  Finally the exit inside the blue box itself is
located at <0x37f436d,0xc1ffa3c>.  You will take a lot of damage in the
process, even with lots of armor and health, however, there are a few
invulnerability artifacts on the level which will protect you.  One is next
to the wall where the launcher and chaingun are, and the other is inside a
central shack that opens when you enter a nearby enclosure to pick up the
green armor.

(10-2): Where are the secrets in DOOM?

*10-2-1*: DOOM I Secrets

        A HUGE thanks to Paul Falstad for making this section possible.

*10-2-1-1*: Secret Master List

======== ================   ============   ================================
 1  68 < b700000,f1000000> ( 2928, -3840) (oddly color wall after zigzag)
 2  69 < ccd0000,f0f00000> ( 3277, -3856) (shotgun behind tower in zigzag rm)
 3  70 < dda0000,f0e00000> ( 3546, -3872) (elevator behind tower in zigzag rm)

 1  21 < 5ec0000, 3c80000> ( 1516,   968) (door to outside in NE)
 2 106 < 2200000,fc800000> (  544,  -896) (door to E rm w/backpack in maze)
 3 116 < 1380000, 1200000> (  312,   288) (door on SE side of small structure
                                           at beginning)
 4 140 <f9b80000, 5b80000> (-1608,  1464) (door before lift to ridge w/imp)
 5 188 <f7270000,fe8d0000> (-2265,  -371) (path to chainsaw in W part of maze)
 6 194 <f8500000, 1400000> (-1968,   320) (door to extra armor on way to
                                           chainsaw rm)

 1  40 <fbc00000,fad80000> (-1088, -1320) (door N of level 9 switch)
 2  51 <fa200000,f6b00000> (-1504, -2384) (corridor N of drawbridge to level 9)
 3  73 <fd8c0000,f7a00000> ( -628, -2144) (door in E corner behind blue door)
 4 134 <f3c40000,f8240000> (-3132, -2012) (door behind SE niche
                                           in yellow key rm)
 5 159 <f66d0000,fc140000> (-2451, -1004) (rm w/backpack past green tunnel)
 6 167 <f5240000,fb240000> (-2780, -1244) (corridor behind N niche in
                                           yellow key rm)
 7 174 <f6c80000,fbe00000> (-2360, -1056) (secret door to chaingun)

 1  71 < 61d0000,   80000> ( 1565,     8) (rm E of green trench)
 2  88 < 6000000, 1250000> ( 1536,   293) (supercharger)
 3 118 < 7880000, 3d80000> ( 1928,   984) (backpack rm at start)

 1   7 <f8aa0000, 3390000> (-1878,   825) (hidden door W of 2-pillar chamber)
 3   5 <f8a00000, 2f80000> (-1888,   760) (hidden door S of #1)
 2   3 <f8a00000, 2c00000> (-1888,   704) (steps outside, S of #2)
 4  49 <fc700000, 5000000> ( -912,  1280) (hidden door E of N elevator behind
                                           yellow door)
 5  58 <fdb00000, 7740000> ( -592,  1908) (shortcut to W side of darkroom)
 6  69 < 1660000, 1480000> (  358,   328) (shotgun room E of 1st stairs)
 7  95 < 46c0000,  ec0000> ( 1132,   236) (hidden door in toxic lake)
 8  99 < 59c0000, 2f50000> ( 1436,   757) (path to computer map rm)
 9 110 <ff040000, 5c00000> ( -252,  1472) (niche with light amp)

 1  65 < 2640000, 55b0000> (  612,  1371) (room S of door to outside)
 2 169 <fce30000,f8d00000> ( -797, -1840) (supercharger in SW tunnel in
                                           toxic lake behind red door)
 3 181 <f8500000,f6c00000> (-1968, -2368) (exit from toxic lake behind
                                           red door)
 4 190 < 37d0000,fc760000> (  893,  -906) (rocket launcher + invisibility)

 1  71 <fdb80000,ffa00000> ( -584,   -96) (supercharger W of door)
 2  94 < 2a00000,fa800000> (  672, -1408) (path outside to invisibility)
 3 147 <ff1f0000,f72d0000> ( -225, -2259) (ledge in toxic lake S of big pillar)
 4 153 <fe500000,fa100000> ( -432, -1520) (path behind door E of radiation
                                           suit in lake N of big pillar)

 1  59 < 2040000, 1800000> (  516,   384) (rm E of corridor to 1st door)

 1  20 < 4200000, 4800000> ( 1056,  1152) (door to NE room)
 2  65 < 5000000,fe000000> ( 1280,  -512) (chaingun in lake in SE)

 1   3 < 1ee0000,ffde0000> (  494,   -34) (rm with plasma gun)
 2   5 < 4180000,  800000> ( 1048,   128) (red key)
 3  52 <ff200000,  800000> ( -224,   128) (thin corridor with health bonuses)
 4  91 < 1940000,fe480000> (  404,  -440) (computer map behind red door)

 1  26 < 4010000,fff40000> ( 1025,   -12) (chainsaw N of crushing ceilings)
 2  45 < 4200000, 2100000> ( 1056,   528) (plasma rifle on pillar)
 3  60 < 8160000, 3920000> ( 2070,   914) (corridor N of 3rd circle in SE)
 4 109 < 9e00000, 5e00000> ( 2528,  1504) (supercharger NE of blue key)
 5 128 <  480000, 7200000> (   72,  1824) (way to backpack, N of blue
                                           light rooms)
 6 137 < 33b0000, 7110000> (  827,  1809) (hidden room E of #5)
 7 140 < 3dd0000, 55b0000> (  989,  1371) (computer map, S of #6)
 8 146 < a700000, fda0000> ( 2672,  4058) (rocketbox behind E yellow door)
 9 160 < a520000, f200000> ( 2642,  3872) (rocket launcher behind E
                                           yellow door)
10 164 < a5a0000, e700000> ( 2650,  3696) (ammo box behind E yellow door)
11 176 < 4a00000, fc00000> ( 1184,  4032) (chaingun on pedestal in N)
12 236 <ffdc0000, ac00000> (  -36,  2752) (shotgun ammo behind lowering box)

 1  37 < 1e00000,fff80000> (  480,    -8) (door in N of pentagram lake rm)
 2  65 <fbc60000,  e40000> (-1082,   228) (plasma rifle in SW)
 3  97 < 2780000,fea00000> (  632,  -352) (door in SE of pentagram lake rm)
 4 103 < 3600000,  680000> (  864,   104) (way into imp cage w/backpack)
 5 119 < 5780000, 3020000> ( 1400,   770) (rad suit S of toxic)
 6 121 < 8550000, 3d50000> ( 2133,   981) (supercharger E of toxic)

 1  10 < 8000000,fd400000> ( 2048,  -704) (supercharger room N of big toxic O)
 2  16 < a000000,ff6b0000> ( 2560,  -149) (niche just N of computer map)
 3  19 < 5800000,ff130000> ( 1408,  -237) (plasma rifle E of northern O)
 4  36 < 68e0000, 2280000> ( 1678,   552) (stimpacks in N part of lava room)
 5  53 < a0b0000,  970000> ( 2571,   151) (room S of crushing ceiling, E
                                           of lava room)
 6 107 < 5700000,fe300000> ( 1392,  -464) (mega armor SW of lava room in NE)
 7 120 < 3800000,fb300000> (  896, -1232) (room w/invisibility W of toxic O)
 8 165 < 3600000,f5200000> (  864, -2784) (berserker S of zigzag in S)
 9 182 < 7e80000,f5480000> ( 2024, -2744) (supercharger near exit)
10 188 <fecf0000,f4f80000> ( -305, -2824) (hidden rm just S of starting point)

 1   8 <fbe00000,  a00000> (-1056,   160) (chainsaw in S middle)
 2  11 <f9c80000,fe780000> (-1592,  -392) (anti-rad suit in circular stairway)
 3 121 <fea00000, 9000000> ( -352,  2304) (rm near exit to level 9)
 4 126 <fb840000, 8920000> (-1148,  2194) (secret imp rm E of starting point)
 5 186 <f28d0000, 1f30000> (-3443,   499) (niche N of fake fire)
 6 188 <f2250000, 4730000> (-3547,  1139) (rm with baron in cage)
 7 219 <f83c0000, 87b0000> (-1988,  2171) (secret imp rm W of starting point)
 8 229 <f2a40000, 8c00000> (-3420,  2240) (energy cell in NW niche in toxic
                                           lake in NW)
 9 234 <f3c30000, 4a00000> (-3133,  1184) (room W of #10)
10 238 <f4e10000, 4a00000> (-2847,  1184) (lost soul rm thru teleporter in #5)

 1   0 <ff800000, c200000> ( -128,  3104) (invisibility, etc. by skull
                                           pedestal in NW)
 2  16 <fbc00000, 9400000> (-1088,  2368) (long N-S room in NW with
                                           chaingun & lite amp)
 3  48 < 6190000, c600000> ( 1561,  3168) (corridor leading N out of
                                           fake exit)

 1  44 <  200000,ffa50000> (   32,   -91) (room w/rocket launcher &
                                           teleporter in SW)
 2  72 <ffe00000,fd140000> (  -32,  -748) (rm w/switch behind red door in SW)
 3 250 < d0c0000, 3a40000> ( 3340,   932) (computer map rm in E middle)
 4 284 <  900000, 5ce0000> (  144,  1486) (plasma rifle rm in NW)
 5 294 < 5e00000, 7e00000> ( 1504,  2016) (supercharger just E of starting pt)
 6 301 < 18d0000, 7750000> (  397,  1909) (chainsaw rm in NE)

E2M8: [none]

E2M9: [none]

 1  25 <fc5c0000, 7600000> ( -932,  1888) (rocket launcher rm)

 1  19 < 6e40000, 7d40000> ( 1764,  2004) (wall blocking way to chaingun in NE)
 2  28 < 2720000, c080000> (  626,  3080) (hallway to rocket case at tip
                                           of middle finger)
 3  58 < 24a0000, 5280000> (  586,  1320) (plasma rifle near 2nd finger fm W)

 1  71 < 4600000,ffa00000> ( 1120,   -96) (rm E of northern niche in
                                           E corridor with dark niches)
 2 110 <fd900000, 1f00000> ( -624,   496) (rm just N of lava maze with BFG9K)
 3 154 <fec00000, 3a00000> ( -320,   928) (computer map in SW corner of
                                           N chamber near exit)
 4 164 < 47a0000, 4510000> ( 1146,  1105) (rm with rocketlauncher N of #1)
 5 184 < 1c80000, 1c00000> (  456,   448) (chaingun in SE niche of toxic lake)
 6 187 <   00000, 3a00000> (    0,   928) (ammo in SE corner of N chamber
                                           near exit)

 1  91 < 4fe0000, 2630000> ( 1278,   611) (rm in NE with SW window where you
                                           can shoot demons)
 2  98 <ffe00000,fd040000> (  -32,  -764) (BFG9000)
 3 124 < 6c00000,fd9c0000> ( 1728,  -612) (radiation suit in NE)
 4 177 <feb80000,fae00000> ( -328, -1312) (secret rm with rockets in W side of
                                           rm S of BFG9000)

 1   1 <faa00000,fc400000> (-1376,  -960) (light amp rm)
 2  97 < 30e0000,  730000> (  782,   115) (chainsaw E of center chamber)
 3 106 <ff200000,ffb60000> ( -224,   -74) (S stony structure in center)
 4 108 <  8a0000, 1200000> (  138,   288) (E stony structure in center)
 5 128 <f7420000, 25d0000> (-2238,   605) (westernmost room with plasma rifle)
 6 132 <fdb60000, 1200000> ( -586,   288) (W stony structure in center)
 7 178 < 1e40000, 8e00000> (  484,  2272) (rocket launcher in most northern rm)
 8 204 <ff200000, 28a0000> ( -224,   650) (N stony structure in center)
 9 237 <fad80000, 5a00000> (-1320,  1440) (secret door to NW in W part of
                                           N corridor; leads W to lava room)
10 257 <fab40000, 6200000> (-1356,  1568) (radiation suit in NW chamber)

 1  77 < 3e40000, 39c0000> (  996,   924) (energy cell in NW-SE oriented
                                           structure with cages at entrance)
 2  88 < 3800000, bdc0000> (  896,  3036) (in front of door to level 9)
 3  92 < 1800000, a400000> (  384,  2624) (chainsaw)
 4 121 < 8030000, 19c0000> ( 2051,   412) (plasma rifle on NE end of
                                           small building with 2 teleporters)

 1  80 < 7800000, 5350000> ( 1920,  1333) (BFG9000, in NE)
 2  84 <fb600000,fe680000> (-1184,  -408) (supercharger in pentagram)
 3  98 <fd2c0000,fc940000> ( -724,  -876) (secret rm SE of pentagram rm)
 4 119 <fd800000, 7920000> ( -640,  1938) (plasma rifle & energy cells,
                                           past teleporter in SE)

E3M8: [none]

 1  23 <fcdc0000, 7600000> ( -804,  1888) (secret rm W in rm just S of
                                           fake exit)

*10-2-1-2*: Secrets in Detail



# Just after the zigzag look right for the oddly colored wall <0xBA389D6,
  0xf0e054ec>.  Push it for corridor to a open place with a blue armor vest.
# After you cleaned out the exit room, go back to the zigzag room and look
  right for the shotgun (the tower with the Imp should be lowered now)
# For DOOM v1.2, a secret area has been added in the above secret room:
  look in the SE corner <0xdeff476,0xf0effdc2> for the elevator.  You'll find
  some armor bonuses up there.  The elevator lowers when you are at the
  entrance <0xb96c465,0xf4879655> in the north, so you'll have to run fast to
  get it.


# The small structure you face when you begin, has a secret door in the SE
  corner (the lighter wall part) <0x15005a8,0x121e8ad>.  Behind the door is a
  room with a red switch.  Pushing that switch will open a secret door in the
  northern corner of the stairs in the east <0x60ada92,0x3affa0b>.  You can get
  outside and collect a supercharger and a chaingun.
+ Behind the red door you'll see a stair twisting to the right.  On the top is
  an indention to your left <0xf9900144,0x3a49ddd>.  If you step on it, it will
  drop down.  You will find enemies to your right, and you will also see (but
  not be able to get) the chainsaw.
# A bit ahead you'll see a lift.  Push the first panel to your left
  <0xf9d0052a,0x5aa56a6>.  You'll be able to kill those Imps from the ridge.
# In the southern part of the maze (to get in, pull the switch behind the pillar
  in the green toxic directly to the right behind the red door <0xfdc004de,
  0x446230f>), shoot the middle most western wall (the one behind the green
  armor vest) <0xf79e0d81,0xfe82feac> for access to the chainsaw (push the
  switch in NW to lower the pillar so you can get it).
  In the same hidden area is some extra armor hidden behind the eastern wall in
  the northeastern corner of the stairs <0xf82fdc62,0x151532f>.
# In the most eastern part of the maze, push the wall between the white stripes
  <0x1eff099,0xfc88d4d4d3> for a backpack.


+ The strange grey wall straight ahead beyond the first door you open is a
  secret drawbridge.  The switch for the drawbridge is in one of the chambers
  described below.
# In the room in the NW (the one that opens as soon as you push the red button
  and that contains the yellow key) are TWO secret passages (the second niche
  on your left <0xf3c7ca46,0xf7dfc822> and the second niche on your right
  <0xf5ac3fd1,0xfac4d713>), both will open when you're on the stairs but will
  close again after a (very) short while.  Go to the stairs and then run like
  hell as soon as you hear them lower. It'll help when you shoot the drums that
  might get in the way.
# In the northern niche (leading to a rocket launcher and a green armor) is a
  secret room in the SE corner (just follow the green stuff to the right).
  Run fast for minimum damage.  You'll see a backpack and the switch for the
  drawbridge at the beginning.  To the east is the exit (a lighter colored
  wall part <0xf6aff87a,0xfbd990b9>) through another secret chamber
  containing the chaingun.
# In the south-eastern niche (the second on the right) is a supercharger (pull
  the switch on back of the pillar).
# The drawbridge should be lowered now.  Cross it, but be careful! There are
  a lot of Imps lurking behind automaticaly opening doors.  My tactic is to
  select the chain gun, run forward and back up as soon as you hear the doors
  open.  Then take them out at your leisure.  Note that you can also shoot some
  of them via the secret `window' in the SE <0xf9480573,0xf8b2d736>.
+ In the north of the room is a corridor, follow it to find the hidden-level-
# To the north of the room with the hidden-level-switch is a elevator, push the
  wall <0xfbe7f1f6,0xfaafee8c> to lower it, so you can get the rocketbox.
# Behind the blue door in the eastern corner is a secret door (the lighter
  patch in the SE <0xfd6ffcd8,0xf7a33c3b>).  The chainsaw, a supercharger, a
  blue armor and a partial invisibility is available.


You start facing a open space with a cage full of Imps in the middle. The
following rooms are described relative to that cage.

+ In the northeast is a pentagram on the floor.  If you touch it, numerous
  enemies will warp in.  Try walking around it and then running to the
  corridor.  That way you can pick them off one by one.
+ In the eastern room is a lift/trapdoor at the middle of the eastern wall
  <0x75cf281,0x2fa03b> (the highlighted patch on the floor).  To the NE are a
  green armorvest.
# Also in the eastern room is a lift/trapdoor in the SW-corner <0x6102f19,
  0xff10138d> leading to a indoor lake with the chaingun.
# The same area is accessible via the lift/trapdoor in the NE-corner
  <0x3d000fe,fcd013ff> of the southern room.
# In the northern chamber, push the middle eastern wall <0x3efe3b3,0x479d0cd>.
  You'll get into a chamber with several high pillars.  The pillar at the far
  side of the room <0x7ad637b,0x423de32> lowers when someone is on the stairs.
  Just run on it, wait for it to rise, and 'jump' to the other pillars by
  running fast counter clockwise.
+ To get to the end of level switch, run down the trench.  To the NW is a
  isle with the switch and to the south is the lift upstairs.
+ Although they don't count as secrets in themselves, getting on the
  five pillars, each with a weapon or bit of ammo on it, in the secret
  room on the right hand wall of the room with the ooze trench and
  exit, is one of the more challenging things to do in the game.
  Basically, the room on the secret level of episode one "Military
  Base" contains five pillars of increasing height as you go around
  clockwise, along with a lift which lowers when you are on the entry
  stairs, allowing access to the first and highest pillar. The key is
  to go around each pillar in a counter-clockwise direction. Just
  running and jumping toward a pillar isn't enough, as you will go over
  it but fall off the far side, and this can only get you to the first
  and tallest pillar, and the shortest (or maybe the first two on
  either end if you manage to swipe the item off the top of the second
  pillar before falling). The key is to shift+forward run at each
  pillar, take off and jump toward it, and right when you reach it,
  briefly press the down arrow to move backward. This will stop your
  running and you will be standing still on the next pillar. If you
  move back too soon you will hit the pillar and fall to the ground;
  too late and you run off the far side. It's best to give yourself a
  running start for each pillar and line yourself up so you will be
  jumping over the minimum distance possible. Using the automap under a
  high zoom level can help here. This actually isn't as hard as it may
  seem to get right. I understand some can do this all in one fell
  running swoop by turning in mid-routine, but this is a surer way.


# The light wall to the left in the beginning (before the door) <0x785a47f,
  0x45005ef> hides a backpack.
# The south exit from the round chamber (the one with the radiation suits)
  leads to a trench.  Follow the trench east for the rocket launcher and a
  supercharger.  To get the supercharger, simply stand on the left side of
  the lift and press the switch.  If you are just barely on the lift, you
  can reach the switch while on the lift.  Follow the trench west to get


# The chamber in the middle (behind the first stairs you encounter from the
  start) has a secret chamber to the south (behind the drums) <0x15a4aa6,
  0x1a0025b> with a shotgun.
# In of the east of this chamber is a toxic lake.  In the SE-corner of the
  toxic is a secret passage (the strangely colored wall) <0x466e20d,0x12009bc>.
  There is a rocket launcher and a blue armorvest.
+ In the NW behind the yellow keycard door is a chamber with two pillars and
  an isle with a switch in the green stuff.  In the indention in the west
  <0xf8e024a0,0x34ff9c5> is a secret chamber with the antiradiation suit. The
  south wall of this chamber hides another room with the chainsaw. The south
  wall thereof gives away to let you outside and get the supercharger.
  You can get the blue armor in the NE-corner by stepping on the northern
  pillar when it's down, waiting until it rises again and then 'jumping'
  over.  Ammo can be found by repeating the same action on the souther
# Two platforms with Imps hidden in the walls behind the yellow keycard door
  act as elevator in DOOM v1.2.  The southern one doesn't lead anywhere.
  The northern one <0xfc2fd5ee,0x4f92783> has a secret wall to the east which
  leads to a secret room with a partial invisibility and a shortcut to the
  darkroom (via the north).  The pentagram is a teleporter back to the
# In the north eastern chamber (the one with the blue floor and the blinking
  light) has a secret chamber to the SE <0x52fbab5,0x3d001f3> with a backpack,
  a chaingun and a computer map.
# In the northern darkroom is a partially hidden chamber to the SW.  The best
  way to get there is to follow the wall left.  You'll find the night vision,
  which is very useful in sniping those baddies in the dark.
+ In the northern darkroom the top of the /\ in the middle wall is also a
  secret door, but as far as I can see this isn't really useful (maybe for
  dashing for the exit?)


+ At the first 'crossing' you encounter, look in the NW corner.  There is a
  partially hidden chamber <0xfd4ff0b2,0xfe5ab835> with some ammo, health and
  a green armor vest.  There are also some Imps there, so to be safe, fire a
  shot into it to detonate the barrels and kill them.
# Behind the red door in the southwest is a green lake.  In the NE-corner
  is an anti-radiation-suit.  In the 'middle' (the tunnel in the SW) is a
  supercharger.  In the SE-corner is a nightvision, a partial invisibility,
  a blue armor and the exit from the lake.
# Just before you are by the blue door there is a secret chamber to the
  south.  Before you're at the blue door, there is a tower with Imps
  <0x31dc6cd,0xfdc354b5>.  When you reach the blue door it will lower so you
  can get in.  You will see an anti-radiation-suit. Push the south wall for a
  backpack, a rocket launcher, a partial invisibility and a back way into the
  room with the yellow key.
# In the same area as where the lowering tower is, is a corridor to the north.
  As soon as you get the yellow key, it will be accessable.  The twisting path
  over the toxic waste will lead to a backpack and a door to the outside. There
  you will see a supercharger on a pillar <0x1125332,0x6c93ef6>. The pillar
  will lower as soon as someone goes near it. Step on it and as soon as it has
  risen, press the wall to the west to get inside the complex again.
+ In the room immediately before the ending room, there is a radiation suit
  available behind one of the pillars.
# In the most eastern corridor is a strangely colored wall <0xd2ffa4f,
  0xf9fc115f>.  Push it to get the computer map.


# In the southwest is a big pillar <0xfe5cda63,0xf7ff97d9> that will descend
  when you are on the stairs east of it.  Stand on top of it, wait until is
  has risen sufficiently and jump on the ledge in the NE <0xffdfe6c0,
  0xf9237c97> for the computer map or the south lake in the NE corner
  <0xff1e2866,0xf72ffeb0> for the chaingun and (when you leave via the secret
  door to the east) a backpack.  Jump in the lake in the north and run fastly
  to the tunnel in the NW <0xfdf75b77f,0xfa229120>.  In the west of that tunnel
  is a radiation-suit and in the east behind the door with the light are some
  goodies and a switch.  Throwing the switch will allow you to get to the
  chainsaw later on in the room in the extreme SW <0xfacc64c4,0xf5a40aa1>.
  Leave the tunnel via the north and look behind the pillar <0xfea017a9,
  0xfacffbc5> in that lake for blue armor.  Follow the acid to the north to the
  supercharger <0xfdb37a3a,0xffa1e2e2> and leave via the east.
# After you get the blue key in the northwest, two hidden areas will open to
  free Imps and former humans.  The secret room in the middle of the map
  <0x1319742,0xfa50049c> has a false wall to the east which leads to
  outside so you can get a partial invisibility.


# The only secret room <0x1cfdaa6,0x17bdce1> is in the east in the corridor
  leading to the first door and contains a supercharger.
+ Note that there is a map in the east of your starting point.



# The SE-corner <0x63aba49,0xfdd82d07> of big room in middle (the one with
  the windows to the east, the south and the west) turns into a teleporter to
  the plasma-gun after you pull the switch <0x4e7f923,0xfee0883b> on the outer
  west side and push the button on the west side of the little wall that rises
  out of the floor (the east switch opens the passage to the red key).
# In the SW is a indention <0x31cb145,0xfb50105e> with two skull-switches.
  Press the eastern skull-switch first for access to a teleporter to a
  corridor filled with bonuses in the north.
# Behind the red door <0x186bb69,0xfd97f0a8> is a blue mega armor and the
  computer map.


# If you walk along the south border of the storage area (the one with all
  those boxes), you'll bump into a box <0xff9751f6,0xb101ab0> which will lower
  if you are north of it, to reveal some shotgun ammo.
# In the south east quadrant are three circles with parts of the floor going
  up and down.  The northern one has a secret corridor <0x82ff4df,0x22fd506>
  in the north leading to the blue door in the north, filled with
# In the SW area (with three corridors with the blue lights on the ground and
  ceiling) is a partially hidden corridor <0xff85ce0a,0x6b92713> in the NW
  corner of the most western corridor. When you try to get the backpack, the
  wall behind you will close and the wall in front of you will lower,
  revealing some Imps. The door behind you will open after a while. The
  SE corner <0x2afe532,0x7011ab87> (the black-colored wall) is the
  secret door to a small chamber.  The SE corner <0x3682291,0x6ebaa52>
  of that small chamber (the wall with the small green light) hides a
  corridor <0x4afeea4,9x667fa8e> back to non-hidden territory (the
  lightly colored wall).  The most south part of the corridor
  <0x414d0b4,0x5d0039e> (the black wall part) gives away to a
# In the south middle quadrant is a room <0x1baafb3,0x1d7344b> with two
  pillars, one khaki, one with tubes (to get there leave the three
  corridors with the blue lights via the way you came in.  Turn right
  and first left. The room on your left [east] is the one you seek).
  The west (khaki) pillar <0x31dc5c4,0x2901565> has a switch on the north
  side, with which you can lower the eastern pillar to get the plasma
# In the south middle quadrant is a corridor with skull crushing
  doors.  To get by them, run forward as soon as they start to go up.
  Take them one at a time.  The middle one <0x3f4c349,0xff1006b4> (third
  one from either side) has a secret passage in the north ridge, leading
  to the chainsaw.  When you get it lost souls will try to get you from
  hidden rooms in the south and east.
+ The room <0x6ec4d6b,0x3a0ad08> with the yellow keycard in the south
  middle has a bridge hidden under the red blood, following blue lights
  on the ceiling, just walk forward and back again fast to make them
# The western room behind the yellow door <0x456db4c,0xdc9ca53> contains
  the chaingun, just flip the switch!
# In the eastern room <0x852f5ab,0xdadd4d9> behind the yellow door
  you'll see three rooms to your right and three auto-rising pillars to
  the north. You can get the backpack on the middle pillar by running
  over the pillar when it starts to rise or later on. The switch on the
  eastern pillar <0x95f38f8, 0x11901ab9> opens the middle door
  containing the rocket launcher.  Flip the switch on the middle pillar
  <0x85ba244,0x11900694> for the south chamber (with ammo) and the one
  on the west pillar <0x75fa7ef,0x11900ad> for the north chamber
  (containing a rocketbox). It's best to pull all switches after each
  other.  Note that the pillars lower as soon as you enter one of the
  rooms, so you can't open any doors after that! (but you can get the
# To get the last secret go into the room with the blue keycard,
  <0x9e4f2bb,0x5affb22> and look up at the four corners.  Note that the
  extreme southeast corner is lit up unlike the other corners. Go and
  stand in this corner and face along the wall.  The platform with the
  supercharge on it will lower <0x9e41c9a, 0x5eff45c>.  Run across and
  get it before it rises again.  It will only go down once, so you only
  get one chance at it.  This is one of the harder secrets in all of
  DOOM to find and get to.

# In the most SW corner of the map is a corridor <0xfba6989a,0xfed0450f>
  to the room with the blue key containing the plasma gun.  To get the
  plasma gun, jump in the red blood and run north (right) fast.
# In the middle south is a room with a five-sided green lake.  The wall
  <0x2847ab9,0xfe90013e> to the south east (the part with between the
  light lines) offers a shortcut.
# The next secret on this level is similar to and next to the one
  above.  You can get out of the room with the green lake
  <0x25ff9c6, 0xfe9f8db4> via a one way secret door on the wall in front of
  the main entry way, which leads back to the room with the imp cage.  The
  other secret door above refers to a one way door into this room which is on
  the wall across from where the rising and falling platforms with candles on
  them are.
# In the south east is a partially hidden cage with Imps
  <0x1de36ff,0x10156d>.  You can enter via the NW corner <0x2effa57,0x951b16>
  to get the backpack.
# Follow the corridor behind the blue door through the open area and the room
  with all those pillars and blinking light to the green toxic stuff.  If you
  go around the corner <0x52fff7d,0x313783c> in the SE, you will find a
  radiation suit.  In the middle of the eastern wall <0x6729d81,0x42cd91e> of
  the green stuff is a corridor to a room with the supercharger in the NE
  corner <0x85000da,0x3eac965>.

# In the middle of the south wall <0xfd743e02,0xf5510517> of the beginning room
  (directly opposite to the TL's to the north), hides a room with the shotgun.
# Take the teleporter to big room.  In the north is a elevator.  Press the
  head left of it to go up.  You'll see a green armor and a computermap.
  To get them push the little red pillar <0xadc846c,0xfebfff01> with the skull
  on it in the NE corner.
# To the north of the big O formed by green toxic waste is a secret door
  <0x59bf44d,0xfb6fe831>. It opens if you have walked via the corridor
  <0x75b231a,0xf6c3a683> in the SE of the big O.  There is a supercharger and
  radiation suit. (Don't forget the partial invisibility south to the entrance)
# To the west of the big O with green toxic waste is a corridor with a T to the
  north <0x213d209,0xf9a64b57>. To the east of that corridor is a secret wall
  <0x27fad41,0xfab20726> with a partial invisibility and a chaingun. Shoot the
  wall to get them.
# In the great round corridor in north, behind the blue door: In the east is a
  `dent' <0x4ed2810,0xff5f15c1> in the ring. This is a trapdoor with a secret
  door to the east and leads to a plasma gun and a teleport to the middle of
  the great round corridor.
# In the great round corridor in the north: follow NE corridor to a room with
  - The small door <0x62ffe68,0x3b6bde> in the SW leads to a small green lake.
    The SW corner has a blue armorvest behind some drums.
  - In NE corner <0x815a37c,0x2c8c810> behind the lava is a secret door.
  Warning! the SE branch of the corridor behind it leads to a crushing ceiling.
  Outrun it and push the green patch <0xa6ffd1d,0x64560a> in the east for the
  exit. The SW branch lets you go back to the lavaroom.
# In the room above, just over the edge of the wall, is a small ledge
  with some medikits <0x6ff9294,0x22b3e1f> on them which normally aren't
  visible from the room and can be missed when running over the lava to the
  secret door.
# In the south middle behind the place where you find the blue keycard, is a
  small twisty path <0x3550d3b,0xf5c84264> high above the acid.  In the SW
  part of the toxic <0x35019f4,0xf510358a> is a berserker.
# After you open the door to the exit, look back and get the supercharger
+ Note: for those of you still searching for that damn switch so you can get
  to the exit: go in the lake and then towards the exit.  The switch is on the
  right wall of the teleporter left of the exitdoor.


# The room where the first door leads to has two secret rooms in the space
  between the room and the stairs.  The doors <0xfb80ba93,0x7dbd7cc>
  <0xf8373cba,0x7e031f5> are facing the south and will open automatically to
  reveal Imps and ammo.
+ The ridges <0xfca60096,0x3febfc5> <0xf71000d0,0x3e622b8> of the green lakes
  of the big room south of the begin both lead back to normal territory.
# In the SW is a roughly (--) shaped room.  In the room NW of the middle
  of this (--) is a switch <0xf3efdd28,0x1367f57> which activates a stair so
  you can walk through the fake fire <0xf29412f7,0x18d236d> in the NW corner.
  The teleporter there takes you to an area infested with lost souls.  The west
  wall <0xf4690f4,0x496136d> with the head leads to another room with
  transporter.  That transporter takes you to the switch <0xfe9fb836,0x92ff44b>
  for the secret level.
# In the room east to the room in the south middle with the room to the N,E,
  and W and a view to the circular stairway in the south, is a secret door
  <0xfbaff1cb,0xae3ad8> in the NE corner (near the cozy head-fire) hiding the
# In the center of the circular stairway is a anti-radiation suit guarded by
  a demon.  The door <0xf94949db,0xfe6d93d0> to it will open as soon as
  you are at the top of the stairs <0xfa165eed,0xfdd56896>.
# The south door directly after the circular stairway leads to two corridors.
  The eastbound corridor is the way to the exit, the westbound leads to C
  formed green lake in the west.  In the north of that lake is a door
  <0xf1a21e52,0xfe94f08f> (behind the ammo clip).  Follow it to a baron of hell
  in a cage.  North of that you will see a long corridor with three doors to
  the east.  The northern and southern doors lead to a ledge around the lake
  to the east.  The middle door <0xf27dc571,0x826c8a6> (the wall part with the
  pentagram over the ugly head) leads to the isle <0xf5420514,0x823f2c1> in
  the middle of the lake, where you'll find a plasma gun. To activate the
  bridge to the isle, you have to push the button <0xf2aff9f7,0xfd1cd93e> in
  the room in the center of the C-formed lake you passed while coming here.
  BTW: If you fall in the lake, the transporter <0xf42dc0b0,0x7500bcf> in the
  indention in the SW brings you back to the beginning.
# In the slime lake mentioned above, not only is there a teleporter,
  but there is also another niche with a cell pack in it


There are no secrets in this level.

+ In the SE where you find the blue keycard, two rooms with demons will open
  automatically. The SW one has a chainsaw behind the brown wall <0x6362f60,
+ Three parts of the mazes are secret.  All the secrets are off the area at
  the north of the level after going down the long narrow passage to the
# The area to the east with the fake exit counts as a secret.
# The area to the north with the goodies on the table counts as a secret.
# The area to the west past the crushing ceiling counts as a secret.


# In the NW is a corridor with ribbles.  The third indention is a corridor
  leading to a very dark open patch.  In the NE <0x126cccd,0x772feab> is a
  switch which opens a room with a chainsaw.  In the SW <0x32fff5,0x3de1cbe>
  is the plasma gun.
# In the SW is a room with a radiation shield and small patches of green
  acid in indentions along the walls.  The SW indention <0x137b2c8,0xff25986d>
  has a corridor to the south leading to a chamber with a rocket launcher and
  a teleporter.  The teleporter will get you to a red door, with a switch
  <0xffe013c6,0xfd1015b7> behind it.  Pushing that switch will open an
  oute door to a secret room in the beginning-room <0x5d894b7,0x76751d7>
  (SE corner) with a supercharger.  Because this room is protected by two
  doors, a second switch must be flipped to open the second door.
+ To open the inner door, flip the switch that is past the blue keycard
  door, up the stairs, and to the left in the room with the acid pool


There are no secrets on this level.



# The small grey chamber before the exit has a secret room <0xfc900da5,
  0x7606912> in west containing the rocketlauncher.


# To get a chaingun, follow the wall to your right (west) to the chaingun
  behind the wall.  The wall will lower when you walk over the red patch
  <0x6b010ab,0x75220b7> to its west side.
+ The second `finger' from the east has some cages with former sergeants.  To
  get into those cages, walk over the red triangle <0x3fa278b,0x817fa0c>.
  The floors of the cages lowers and a wall behind you will come down.
  To lower the triangle column (actually it rises) you want to shoot the
  back wall of one of the six cages the sergeants were in. Shooting it
  raises the pillar exposing the red triangle, walking over which
  lowers the sergeant platforms allowing you to get the stuff in each one.
# In the large circular room at the end of the middle finger is a
# The plasma gun is hidden in the western part <0x2072324,0x4ecdc0e> of the
  pillar you see when you stand with your back to the second `finger' from the


+ In the starting room, a megaarmor can be obtained on a ledge overlooking
  the yard in front of where you start.  When you go up the stairs to the
  right, and then down the elevator to the area which has stairs going down
  to where the blue key is, there is actually a second elevator in the wall
  which leads up to the ledge with the armor.  This second elevator
  <0x48189c,0xfe5f9916> can only be used once, and you must move back
  slightly after pressing the button or else the elevator will catch half way
  up under an overhang.  The armor's ledge does damage so grab it quickly.
+ Directly north of the beginning is a great open place with 4 pillars.
  Pressing the switch <0xfea95756,0xaff327> in the north will lower the middle
  pillar <0xfe921ce9,0xfef4c1db>, so you can get the shotgun.
+ To get to the rooms with the windows to the room in the beginning, go
  north and take both the east and the west stairs, and then south.
# A little north of the middle is a round green lake <0x120905e,0x1754b6d> with
  a lavalike ceiling.  In an indention <0x1c9c5cd,0x1c492ee> in the east is the
# In the SW is a corridor with two platforms (one in the north and in the
  south).  There is a small corridor in the south.  When you follow it, you'll
  come to a T-split.  In the west (right) is an invulnerability, useful for
  running over the lava in the east. Take the turn left (east).  You should be
  on the southern platform of the corridor.  In the south of that platform you
  can see a lava/blood maze <0xfd9760e5,0x1de4aec>.  In that maze you'll find
  the BFG9000 <0xff1ebaad,0xdeec44> in the SE corner and a supercharger
  <0xfe3afdf3,0x2101114> in the NW corner.  You can also get to the lava maze
  by going directly north from the beginning, then taking the west stairs,
  then following the path north.
# One of the most northern chambers (the one just before the blue door leading
  to the exit) has two air shafts flanking a formation you could describe as a
  coach facing north.   When you stand on the coach <0xff6e17cb,0x532520e> the
  wall part west of the stairs south will lower allowing you to get the map.
  The wall part <0xfffcfa97,0x41c62aa> east of the stairs will lower when you
  push it.
# The last two secrets are in the area to the east of the level, off
  the east hall and over the stairs guarded by lost souls.  Just
  entering the room around beyond it with the lava and Cacodemon counts
  as one secret.  Getting to the area past that with the berserk pack
  and armor counts as another.


+ The first room to the west from the beginning has a secret room <0xfebbbdcd,
  0xc4c579> in the SE corner containing the shotgun.
# In the SW (a bit behind the blue door) is a room with a doors to the east
  (the entrance), to the north (where you find the BFG9000 <0xffdaa1b0,
  0xfd07e1fa> in some lava), to the west (where a lot of Imps and a baron of
  hell await you) and to the south.  The south chamber has a secret room
  <0xff49f58f,0xfae5873e> to the west filled with rockets.
# In the south middle east of the blue door is a room with a door to the north
  and a small patch of blue lake on the east side.  Press the wall <0x3ddce70,
  0xf9d91cc3> a bit more north of that patch of blue for a green armorvest.
+ In the middle is a room with two pillars with switches on all sides.
  Here is a rude ascii-chart of the scene to facilitate solving this.
  [#] is a door opened by switch #
  [Y] is the yellow keycard door
  [R] is the red keycard door
  Behind door 2: an invulnerability
  Behind door 3: the yellow key
  Behind door Y: the red key

                  +--+       |   |
                  |  +-------+   +--+
    +-------------+  +      [7] [Y] |
    |            [3] |    ---+---+--+  rest of the level...
    |     --------+--+      [6] [7] |   .
    |            [2] |     +-+[R]+--+   |
    |     --------+--+     | |          |
    |       0         4    | |          |
    |     3 [] 1    7 [] 5 | ++ +-+ +-+ +
    |       2         6    |  +-+ +-+ +-+ <----- secret wall, press it
    .                                 +-+        for a radiation suit

# As drawn above, there is a secret wall <0x6cffeee,0xfdd03be8> in the south of
  the most eastern indention.  It contains a radiation suit.
# The final secret for this level is located to the left of the starting
  room, past the Cacodemon cages and behind the wall.  Using the teleporter
  across the lava to enter the room counts as a secret.


# Take the most western entrance to the cathedral.  Push the west wall
  <0xfc4e8e97,0xfc5dfd80> and get the lightamplifier <0xfad56408,0xfc1fa3ee> in
  the SW corner.
# The most NW chamber (the one with the lava floor) has secret door
  <0xfa4ed057,0x61933f5> to the east with a radiation suit.  The transporter in
  the room leads to the middle of the map/cathedral.
# The east wall <0x2d56f0d,0x9b29c1> of the big central room of the cathedral
  (the one with the four 2x2-teleporters) hides a small niche with a
  supercharger and a chainsaw.  The yellow key is required to open this
# Also the four stony structures to all sides of the middle warp-in are hollow.
  The doors will automatically open each time you warp in to the middle from
  another place (from outside to inside).
# In the cathedral are four 2x2-teleport-places.  The northern two are
  connected to the north by a corridor.  That corridor has a secret passage
  <0xfd48642a,0x56afd0c> in the NW.
# The most northern room has three switches and a teleport with crushing
  The SE-switch opens the secret doors in the corridors to the east and west,
  enabling you to get the rocket launcher and some rockets.
  The NE-switch lowers the blue key in the NW-corner.
  The NW-switch lowers the chaingun in the NE-corner.
  The teleporter in the SW teleports you to the NE corner of the cathedral.
# The most eastern room (east of the exit) has a small pit, from where many
  enemies will warp in.  To the east of that room, behind the skull <0x787fd10,
  0x2eaf2e4>, is the BFG9000.
+ For those of you wondering just which damn transporter you have to take to
  get out the middle of the cathedral: it's the most southwestern of the
  northwestern patch of transporters.


+ In the east is a cubus-formed building on a hexagon isle. The east alcove
  <0xd1027ea,0xfe2234b7> is the way in.  In the NW corner <0xb9d75d8,
  0xfeb0d1db> is the backpack.  Pushing the skull <0xbd80026,0xfe22bffe> on
  the west wall lowers the wall in the SE, releasing the enemies trapped there.
  Pushing the skull <0xc5fdf50,0xfe67fb05> on the north wall lowers the wall
  in the NE, so you can get the radiation suit there.
# In the north is a NW-SE oriented structure with two cages with Imps at
  both sides of the entrance.  That structure has a secret door inside in
  the middle of the NE wall <0x3a60e7c,0x356d9b4> (at the small light on the
  floor) and a teleporter in the middle of the SW wall <0x281e808,0x22e23de>.
  The teleporter will put you on a high structure further north.  From
  there you can 'jump' west and get the chainsaw.  You can get out via the
  transporter in the SE side <0x34a6f68,0x9bd1900> of the structure you warped
# East of the above described NW-SE oriented structure is a small _|_ formed
  building on a small hill.  The building contains two teleporters.  The
  eastern warps you on the NE ridge of the hill, where you can get the plasma
  gun <0x7e352bd,0x1c1c059>. The western transporter also warps you to a ridge
  (NW) of the hill, but there are only some shotgun shells there.
+ The small blue building <0x941bec7,0x293e0bb> in the NE contains a radiation
  suit and cacodemons.
+ All compact flaming red structures contain enemies and a few soul spheres
  or a radiation suit.  Sometimes one of the walls goes down, spilling the
# See Chapter [10-1-3] for information on getting to the secret level.
  This counts as a secret as well.
# The fourth and final secret passage area on this level is inside the
  same building room with the secret teleporter leading to the blue box
  ledge.  On the opposite wall is another hidden wall opening
  <0x3aa61a5,0x365963f> which contains a cell pack.
+ The exit is in the middle west: follow the south wall over the lava, you'll
  see a tunnel <0xfb186e6b,0x54a49e> going north to the blue door, and further
  the exit beyond.

# Beyond the northern blue door is a maze of small lava tunnels.  In the SE
  corner <0x7a37332,0x5bec063> of this maze is the BFG9000 and a transporter
  to the SW quadrant of the map.  In the NW is a transporter <0xff7323ef,
  0x824218c> warping to the SW quadrant, the red key <0xfe3f638e,0x6fd04ca>
  and a red door.
+ There are several pillars in the various lava-lakes with red doors, all
  containing transporters:
  (0) In the most SW lake is in the north a pillar <0xf9e908db,0xfc8d60ac>. It
     warps you to a room where you can see the yellow door.  In the same room
     is also a switch <0xfcaffa88,0x45f8a18> on the east wall, pushing it
     activates a bridge in room (1).
  (1) In the middle (big) lake is also a pillar <19c3b9d,362e08> with a
     transporter. It warps you to the room west of the above room.
     In this room is also a yellow door, in it is a switch that activates the
     bridge to the pillar in the middle of a lake (.
  - In the most northern lake are two pillars (east/west). The western pillar
    <ffa72354,6c46d07> has a transporter to the SW ridge looking out over the
    middle pillar..... The switch <f9d003cc,569d8a4> opens a door???
    The eastern pillar <2d380df,57aafc9> leads to the ridge east, with the
    yellow key...
  - SE: 31ff6e7,faea6d2e> NE of tower, with plasma gun.
  - In the NW lake is in the north a pillar <0xfe1aff7a,0x4093707> containing a
    transporter. It warps you to the yellow door.


+ Not a real secret room, but in case you are wondering: the room in the middle
  contains a plasma gun and a blue armorvest.


+ This level is very similar to E3M1, but is much more difficult.
# Just like in Hell Keep, there is a rocket launcher just in the west of the
  small grey chamber <0xfd20a96c,0x76057af> in the NW.  This rocket
  launcher is not available on Ultra-Violence mode and above.
+ Note that many of the hidden rooms full of enemies (the rooms that open when
  you go over the transporter-lookalike in the NW) contain weapons and other
  goodies.  Most beneficial of those is the BFG9000 in the SW corner of the
  lake (west behind the entrance).