The Official

DOOM 2 LOGO


KEY FAQ

(Remember, if it doesn't say "The Official DOOM ][ Key Faq", it is probably something else!).

Legal crap: This Document is Copyright 1995, 1999 by Richard R. Ward <rrward@gci.net>,
            and Mike Newton  <mik@delusion.net>.  Red Key instructions by Mike Newton.
            Blue and Yellow Key instructions, HTML conversion and other such nonsense
            by Richard Ward.

            This document is NOT a product of id Software. nor is it endorsed in any way
            by id Software.  The use of the DOOM 2 logo graphic should not be construed to
            indicate that id Software endorses or is involved with this FAQ in any way.

            I have tried to make sure that the information in this document is accurate
            (well, the factual stuff).  I take no responsibility for  misuse or
            inability to properly use the information in this document. So there.

            DOOM and DOOM ][ are registered trademarks and/or servicemarks of, and are
            copyrighted by ID software.

            This document was prepared with the Zeppelin-Woody compression algorithm,
            patented and servicemarked by Unicycle and Compukeserve.  Used without
            permission of anyone.  (Software patents suck.)
            

Index


1: A note from the author(s).

2: What is in this FAQ?
     2.1   What is a key?
     2.2   Why do I need a key?
     2.3.1 What is blue?
     2.3.2 What is red?
     2.3.3 What is yellow?
     2.4.1 Why do I need a Blue Key?
     2.4.2 Why do I need a Red Key?
     2.4.3 Why do I need a Yellow Key?
     2.5   What the hell am I talking about?
     2.6   Definition of terms.
     2.7   Revision history.

3: How to get the Keys on different maps of DOOM ][.
     3.01 Entryway
     3.02 Underhalls
     3.03 The Gauntlet
     3.04 The Focus
     3.05 The Waste Tunnels
     3.06 The Crusher
     3.07 Dead Simple
     3.08 Tricks and Traps
     3.09 The Pit
     3.10 Refueling Base
     3.11 'O' of Destruction
     3.12 The Factory
     3.13 Downtown
     3.14 The Inmost Dens
     3.15 Industrial Zone
     3.16 Suburbs
     3.17 Tenemants
     3.18 The Courtyard
     3.19 The Citadel
     3.20 Gotcha!
     3.21 Nirvana
     3.22 The Catacombs
     3.23 Barrels 'O' Fun
     3.24 The Chasm
     3.25 Bloodfalls
     3.26 The Abondoned Mines
     3.27 Monster Condo
     3.28 The Spirit World
     3.29 The Living End
     3.30 Icon of Sin
     3.31 Wolfenstein
     3.32 Grosse

Stuff



1: A note from the author(s).
     This FAQ (and I use the term loosely) is the combination of Richard
     Ward's "The Official DOOM ][ Blue Key FAQ!" and Mike Newton's  "THE
     OFFICIALLY-UNOFFICIAL DOOM II: RED KEY FAQ" as well as new text for
     the Yellow Key (no one felt up to the challenge of doing a Yellow Key
     FAQ, I guess).

     I have no one to blame thank for this FAQ other than maybe Mike Newton
     for letting me steal his idea and his Red Key FAQ.

     Mike's Red Key FAQ was written after reading one-too-many posts asking
     "How do I get the Red Key on level 02 of DOOM ][?".  I guess it was
     better than yelling at them.  :)


2: What is in this FAQ?
     This FAQ is for people having trouble finding the Keys on different
     maps of id Software's game; DOOM ][.  This document does not cover how
     to get the Keys in any other version of DOOM nor any of the freely
     available DOOM pWADs. Nor does it warn you about what kinds of
     monsters will be trying to deny you possession of the glory of the
     Blue Key, the utility of the Red Key, or the necessary evil of the
     Yellow Key, nor of the traps that await you.

     For each level, the keys are listed in the order that you need to get
     them.  Some levels do not have any keys, and on some levels it does
     not matter which order you pick up the keys.


     2.1: What is a key?
          Lobster's New Universally Unreadable Dictionary defines
          "key" as:
               "Key, n, plural keys, ['kee'],
               1. a thingamabob, usually of metal, for moving the
               whatchamacallit of a lock and thus locking or unlocking
               something, if it works."
          In DOOM there are three different keys, (not at all bad) Red,
          (pathetic and stained) Yellow, and (glorious) Blue.  They come in
          two varieties; key cards (below left) and skull keys (below
          right).  Key cards and skull keys are functionally identical,
          a blue skull key will open the same door as a blue key card,
          they just differ in how they look.

          Blue Key <-- Key Card                          Skull Key --> Blue Key


     2.2: Why do I need a key?
          Because some of the doors in DOOM ][ are locked.

     2.3.1: What is blue?
            Lobster's New Universally Unreadable Dictionary defines
            "blue" as:
                 "Blue, n, [blew],
                 1. A glorious color somewhere between green and purple.
                 The best darned color in the whole world."

     2.3.2: What is red?
            Lobster's New Universally Unreadable Dictionary defines
            "red" as:
                  "Red, n, [red],
                  1. A pretty nice color between orange and purple.
                  Goes well with white or black.  Too bad the commies
                  had to use it for so long."

     2.3.3: What is yellow?
            Lobster's New Universally Unreadable Dictionary defines
            "yellow" as:
                 "Yellow, n, [yell - o]
                 1. A dingy and soiled color somewhere between green
                 and orange.  Of all the colors, this one truly sucks."

     2.4.1: Why do I need a Blue Key?
            Are you nuts?!  The Blue Key is the most beautiful thing
            in the world!  Besides, it opens locked doors that need
            the Blue Key to open them.

     2.4.2: Why do I need a Red Key?
            To open doors locked with red keys.

     2.4.3: Why do I need a Yellow Key?
            I guess you could use them to open doors locked with yellow
            keys.  I usually throw mine in the compost heap before the
            color rubs off on me.

     2.5: What the hell am I talking about?
          I haven't the faintest idea.

     2.6: Definition of terms:
          "Jump", there is no jumping in DOOM ][.  When I use the
               word "jump" I mean that you should run off the edge
               of a raised platform (Shift+UpArrow).

     2.7: Revision history:
          Version 1.0 and 1.1 released in early 1995.
          Version 1.2 October 1999.  Minor errors fixed and
          document converted to HTML.

3: How to get Keys on different maps of DOOM ][.
          (Information you might actually use (imagine that)!)
MAP 01 - "ENTRYWAY" - Sandy Petersen
No Keys MAP 01 is completely devoid of any keys at all. :(

MAP 02 - "UNDERHALLS" - American McGee
Red Key

As you travel around the river you'll come to a room where you can see the red key in a window of a building surrounded by AstroTurf(TM). Stay on the ledge above the turf and follow it around to the left. You'll see a window. Jump from the ledge through the window (over the turf). Proceed up the stairs to the RED KEY.
 
Blue Key

From the RED KEY, go back to start, flip the switch behind the red bars. Take the west river to a room with two holes in the floor. Go down the southern hole. The BLUE KEY will be to the east.
 
Yellow Key Map 02 is not soiled with the YELLOW KEY.

MAP 03 - "THE GAUNTLET" - American McGee
Blue Key

From start, go to the west until you find the BLUE KEY.
 
Red Key

The RED KEY is in the grassy area with the demons, spectres, and imps (oh, my!). (near the exit).
 
Yellow Key Map 03 is not tainted with the YELLOW KEY.

MAP 04 - "THE FOCUS" - American McGee
Blue Key

From start, go south and up the stairs until you get to a room with grey bars in the windows. Hit the switch (this will lower the BLUE KEY). Go down the stairs and go through the door to the east. Go south and west to the BLUE KEY.
 
Red Key

Go through the blue door. You can see the RED KEY just ahead of you up on a ledge. Continue through this room to the next door. Just inside this door, on your left, is a small crate in the corner. Back yourself onto this crate and a larger crate will fall in the middle of the room. Get on this lifting crate and you can now easily get the RED KEY.
 
Yellow Key From the RED KEY turn left, use the teleporter. Go down the stairs and through the red door to the west. Go through the second red door. You couldn't miss that sorry excuse for a YELLOW KEY if you tried.
 

MAP 05 - "THE WASTE TUNNELS" - American McGee
Red Key

From the start, go left and through the door (which really isn't a door, just looks like one). Follow the lights to the right through the door. Go to the final door on the left, open it and flip the switch. Turn around and go through the door directly in front of you. Go left and follow the river until it dead-ends. Turn left and head up the stairs. On your right at the top of the stairs there is a door. Go through the door and turn right. Follow this around to the water and there's the RED KEY.
 
Blue Key

From the RED KEY go south then west to the red door. Behind the red door is the BLUE KEY.
Yellow Key From the BLUE KEY go west to the blue door. The YELLOW KEY is on the other side of the pillar.

MAP 06 - "THE CRUSHER" - American McGee
Blue Key

From start, go west to the huge lift. Wait for lift to rise. Jump through the hole in the south wall of lift to the ledge with a switch. Flip the switch and run like hell to the lift that just lowered. The BLUE KEY awaits the brave.
 
Red Key

Go through the blue door and up the lift. Follow around to the left and down the stairs, straight past the red door and through the next door. Go down the lift, through yet another door. Follow the stairs all the way up and run across to where the RED KEY is.
 
Yellow Key From the RED KEY go back up the lift and east to the red door. Follow the grassy path to the south and through the next door. The putrid YELLOW KEY is in the southeast corner of the room with the green slime in the trench.
 

MAP 07 - "DEAD SIMPLE" - American McGee
No Keys Map 07 has no keys at all. Don't stare, it's not polite.

MAP 08 - "TRICKS AND TRAPS" - Sandy Petersen
Yellow Key

From start, turn around and go through the south door. If you survive, you will be burdened with the YELLOW KEY.
Red Key

Go through the yellow door (in the starting room) and follow the path (staying to the left). You can't miss the RED KEY!
 
Blue Key Sadly, this map has no BLUE KEY.

MAP 09 - "THE PIT" - Sandy Petersen
Blue Key

From start, take the north lift. Go as far north as you can. You will run into a lift, hit the switch to the east of the lift. Lower the lift and jump over to the newly raised section. Go around the corner to the south-east (don't fall off) and out into the courtyard. Go back to the newly opened room (just around the corner) and flip the switch. Go north and flip the newly exposed. A door will open to the west. Jump across to the raised ledge. This will lower the platform with the BLUE KEY. Run like hell to the BLUE KEY.
 
Yellow Key

From the BLUE KEY, jump off the platform and go north to the blue door behind the switch. Open doom and hit switch. Run back (south) to the newly opened hidden door. Flip the switch on the north face of the pillar and go through the (now open) door. Jump into the green muck and run to the left (south), hit the switch in the alcove and run to the YELLOW KEY.
 
Red Key There is no RED KEY on this map.

MAP 10 - "REFUELING BASE" - Sandy Petersen
Blue Key

From start, bear east until you get to a long brown courtyard. Take the south door. Go east to a large dark room. Go to the north. On the south wall of this area is a small room with stairs. Go up the stairs. The BLUE KEY will be behind a hidden door in the southeast corner.
 
Yellow Key

From BLUE KEY, go back to the brown courtyard and go to the door at the north end. After the door, take the first right and go to the end of the aisle and the YELLOW KEY will be in the alcove around the corner to the right.
 
Red Key There is no RED KEY on this map.

MAP 11 - "'0' OF DESTRUCTION" - John Romero
Blue Key

From start, go east ¼ the way around the circle. Take the "bridge" to the east and continue east as far as you can go (you will climb two flights of stairs). There will be a small wooden "house". The BLUE KEY is inside.
 
Red Key

Well, you know *where* the RED KEY is (if you don't, just delete DOOM II and go back to PONG:) There are two ways to get it:
  1. Go get the blue key (you don't need it, but you need to go get it). After leaving the blue key area (back to the original path), turn right and then look right. Down in the acid there's a door-like-thing in the wall. Go in it and into the teleporter. From the ledge where you exit, run fast to the RED KEY!

  2. (You actually need the blue key for this one) Go through the blue door and flip the switch. Continue on and follow the newly raised path to another switch and flip it. Jump down and go up the stairs and now there's a path raised to the RED KEY!

 
Yellow Key Map 11 is joyfully free of the YELLOW KEY.

MAP 12 - "THE FACTORY" - Sandy Petersen
Blue Key

From start, go around the building to the northwest corner. Go up the stairs and bear north (and kinda west). Go through the first door you find. Go to the wooden box with the Soul Sphere on top and turn east. Go to the end and turn north (two lefts) and the BLUE KEY awaits the valiant.
 
Yellow Key

From the BLUE KEY turn around and go east to a column with red banners on either side of a door. Behind this door hides the YELLOW KEY like the frightened rabbit it is.
 
Red Key While there is no RED KEY on this level, there is a red door. A sneaky trap if ever I saw one. (Something I'd expect the YELLOW KEY to try and get away with.)
 

MAP 13 - "DOWNTOWN" - Sandy Petersen
Blue Key

From start, go around the grey wall and follow the dark arrow into the alley and up the stairs. Go through the door and go down a hole in the northwest corner of the room. Use lift at the north end. There will be another hole to the north as you exit the lift, go for it. Open the door at the end and the BLUE KEY will be in front of a teleport in the northwest corner.
 
Red Key

From the BLUE KEY go through the door at the top of the stairs and head south to the large arrow on the ground. Follow thepath to the BLUE KEY, stopping at the top of the lift. Take the teleporter rather than the drop and follow the ledge around to the blue door, to the teleporter up to the RED KEY.
 
Yellow Key From the RED KEY, jump off the building and go to the southeast corner of the map to the red door. Ride the lift to the top and there you will spy the pathetic visage of the YELLOW KEY.
 

MAP 14 - "THE INMOST DENS" - American McGee
Red Key

From the start, go right and then right again down the stairs. Follow to second door on right and walk through it and the door behind it. Go to the right and follow to stairs on left, up the stairs and through the door. Directly ahead of you is a diamond-shaped window. Jump through the window to the path dead ahead. Turn left after the second water channel and follow this to the RED KEY.
 
Blue Key

From the RED KEY, go back to the double gated "bridge" (with the self opening doors) and go south and west to a the shack next to the bridge blocked by red skull pillars. Open the shack door and hit the switch. Go over the bridge south until you come to a door. On the other side the fearless will be rewarded with the BLUE KEY.
 
Yellow Key Map 14's purity has not been soiled by the YELLOW KEY.

MAP 15 - "INDUSTRIAL ZONE" - John Romero
Red Key

From the start, take the lift to ground level. Turn right and follow the outside wall around until you see the building (on your left) surround by a small "red-acid" channel. Follow stairs to the top of the building. Once at the top, look right (at the white teleporter). Back up and jump to the teleporter. From the ledge you exit on run straight to the ledge on the building in from of you and flip the switch. Fall into the room in this building and go in the teleporter. Upon exit, move forward a bit and then back into the teleporter again. Get the RED KEY.
 
Yellow Key

(You can get the YELLOW KEY without the RED KEY (you can solve the level without the RED KEY), but I'm not telling you how!) From the RED KEY take the lift down to ground level and go to the grey building with brown buttresses to the east (you can see an Invisibility Sphere in it). Take the lift up to the red door, go through and follow the hall to the teleporter at the end. Use it. From the "warp in" turn around and go to the lift behind you (south). Go east and south and go through a doorway facing west. Go inside. Hidden behind the BFG-9000 is the almost useless YELLOW KEY.
 
Blue Key Flip the switch to raise the stairs and go up and out to the south. Jump off the southwest corner towards the green castle (don't fall in the moat!). Go into the castle. Get the Rad Suit in the northwest corner and then go down the southern most tunnel and flip the switch. Go back to the entrance room and up to the top of the newly formed stairs. Lower the lift at the top and go around the corner to the east and hit the switch. Go back down the stairs. There will be an arrow on the floor pointing to a small hidden door in the wall. Open the door and the hardy adventurer will be blessed with the BLUE KEY.
 

MAP 16 - "SUBURBS" - Sandy Petersen
Blue Key

From start, leave the building you start in. Go to a small lake in the southeast corner of the map. In the slime is a small wooden island. The BLUE KEY awaits atop this island (it is obscured by four boxes of rockets, but nothing can hide the glory that is the BLUE KEY).
 
Red Key

Go to the grey building in the northern area of the map (the one with the funky blue and red firewall inside). Behind the blue door is the RED KEY. You can't miss it.
 
Yellow Key Like all good things, this map is without the YELLOW KEY.

MAP 17 - "TENEMANTS" - John Romero
Red Key

From the start, take the first available left. Follow down the jagged path to the RED KEY. (Mike gets all the easy ones.)
 
Blue Key

You need the RED KEY, from the RED KEY wait for door to open, go to the intersection north of start (with the door that won't open). Behind the RED Door is a switch, hit it. Go across to the other room (who's door is now open) and ride the lift down. Go to the far end of this lower area and hit the red/green switch. There is a door that will lead you back to the start area. Go out of the now open door and across to the east doorway on the acid pit. Go to the northeast corner of the north acid pit and hit the wall (spacebar, there's a hidden switch on this wall). go through the door that opened just to the south of you and hit the switch on the eastern end, raising a bridge across the south acid pit. Go across this bridge and fall into the narrow chasm at the far side. Flip the switch. This will raise you out of the acid and raise a bridge across the north acid pit. If your soul is pure, you may now get the BLUE KEY.
 
Yellow Key From the BLUE KEY go back to the courtyard and go through the blue door to the west. Go to the south and go up the stairs. Turn around and run to the (now) exposed Soul Sphere. Go back up the stairs and hit the (now) exposed switch. Go down the stairs and go up the stairs in the northern part of the room. Follow the path to the green pillar with the beating heart. Turn left (east) and jump in the acid. There the YELLOW KEY awaits like some third-place ribbon at the Science Fair.
 

MAP 18 - "THE COURTYARD" - Sandy Petersen
Yellow Key

(*SPOILER*) Shoot the door to open it and take the first left into the courtyard. (*END SPOILER*) Go to the northwest corner and the YELLOW KEY waits like a discarded cigarette butt.

Blue Key

From the YELLOW KEY go to the east side of the "pillbox" on the raised ledge to the east of the YELLOW KEY. Open the yellow door and use the teleport within. The BLUE KEY is hidden behind one of the green pillars.
 
Red Key Hmmph, looks like someone at id decided not to include the useful RED KEY in this map.

MAP 19 - "THE CITADEL" - Sandy Petersen

You can get the keys in any order so I'll list them in alphabetical order

Blue Key

From start, get into the castle (you'll figure it out), go west to a room with several doors and a switch. Hit the switch and go through the west door. Hit the north switch and a teleport willl open in the wall. Use it. Turn around and take the south passage. Open the hidden door just past the ammo box in the window and lower the lift within (far wall). After the lift raises, RUN (fast as you can) out of the window and over the moat to the red building. Go in the north entrance and flip the switch in the "guard shack". Go through the west opening and use the NorthEast teleport. Go straight ahead and you will receive the blessings of the BLUE KEY.
 
Red Key

From the start, follow the path to room with stairs on both sides and 3 doors. Go through the door on the right, flip the switch to raise the stairs, and go through the secret door at the top of these stairs. Run fast up the stairs inside this door veering right toward the teleporter on the ledge in the corner. Upon exit, move forward then back into the teleporter again. In this room, shoot the west wall to raise the floor. Hit the switch on the raised floor, get on lift, and jump to the raised floor. Go through the door and follow path to the RED KEY.
 
Yellow Key From the start, go to the same place that opened the first teleporter to the BLUE KEY. Wait for the door to close. Hit the switch on the south side and go back through the newly opened hidden door. Follow the stairs (turning LEFT (never right, ALWAYS LEFT)) to the YELLOW KEY.
 

MAP 20 - "GOTCHA!" - John Romero
No Keys

This map has no keys, poor bastard.

MAP 21 - "NIRVANA" - Sandy Petersen
Yellow Key

From start, take the north teleporter and follow the rings to another teleporter, use it. Hit all four switches under the rocket launcher. Lower the (newly raised) lift and take the southern teleporter (it's the one singing Shania Twain songs :) ). The wall that surrounds you works like a door. The next one lowers by itself. The YELLOW KEY is in there somewhere.
 
Red Key

(You could get the BLUE KEY before the RED KEY, but it'd be more work.)
Go through the yellow "gate", turn right and follow past the blue "gate". Turn right again and jump to the ledge with the switch. Flip the switch and run to the lowered lift in the acid. Get the RED KEY.
 
Blue Key You need the YELLOW KEY, from the YELLOW KEY take the teleport to the big room. Open the yellow gate and run into the acid lake to the tall pillar near the ledge on the northwest edge of the map. Jump over to the ledge. The BLUE KEY awaits to add meaning to your life. (Oddly, you can exit without the BLUE KEY, but I'm not telling you how (like it's really all that hard...).)
 

MAP 22 - "THE CATACOMBS" - American McGee
Blue Key

From start, take the northeast lift. Use the lift in the northwest corner of the acid pit. Take the stairs to the west and follow the passage to the end. You will come to a metal room with a door (located in the north ledge of the acid pit). Behind the door is a teleport that will take you to the BLUE KEY.
 
Red Key

Go through the blue door down the northeast lift in the central area, flip the switch to open the gate. Go through the "gate-thing" toward the "eye-thing". Turn left at the "eye-thing" and hit the skull switch to open the door. Go through the door and hit the skull switch on the left to lower the lift to the RED KEY.
 
Yellow Key Another map undefiled by the YELLOW KEY.

MAP 23 - "BARRELS 'O' FUN" - Sandy Petersen
Yellow Key

(Only one key and they had to use yellow.). From start, go south and use the teleporter behind the door. Go north and use the next teleporter. Go south and hit the switch, and then go back to the north end of the ledge. Use the newly raised platform (hint, if the wall has not lifted, shoot it) and go to the stepped section to the east. Go south again and jump onto the teleporter to the east (in the lava). Turn around and follow the "cave" around once. The lamentable YELLOW KEY awaits behind a newly opened door.
 
Blue Key

This map wallows in the sadness that comes with not having the BLUE KEY.
Red Key This map does not contain a RED KEY.

MAP 24 - "THE CHASM" - Sandy Petersen
Blue Key

From start, go across the "bridge" to the building with the acid waterfalls on the sides. Behind the door the BLUE KEY awaits those brave souls wise enough to decipher the maze.
 
Red Key

Go through the blue door and walk on the thin "wall-thing" straight ahead. Stay right until you see the hangin' dead guy. Walk toward him and the teleporter he hangs from. Head toward the white teleporter in this room. To get the RED KEY hit the skull switch on the right of where you entered. Then the left (directly behind you now), and lastly straight ahead (now to your left). Welcome to the RED KEY!
 
Yellow Key Like any respectable place, it does not have a YELLOW KEY.

MAP 25 - "BLOODFALLS" - Shawn Green
Blue Key

From start, take the east stream past the blood waterfall to the open area with the pillar of blood. Lower the lift on the east side of the area and go into the caves beyond. Bear left and find the teleport that will take you to the glorious BLUE KEY.
 
Red Key

With a BLUE KEY, who needs a RED KEY?
Yellow Key Not on this map (haha!).

MAP 26 - "THE ABANDONED MINES" - John Romero
Red Key

Straight from the start, hit the switch. Walk forward to the end and turn left. Walk to the end again and hit the switch. Turn around and run to the end and left into the now open door. Follow this around the home of the RED KEY.
 
Blue Key

From the RED KEY go back to the intersection with the bright lights and head west. Behind the prison of the red door the BLUE KEY awaits liberation.
 
Yellow Key From the BLUE KEY go back to the intersection with the bright lights and go east. Follow the serpentine path to the blue door. Beyond cowers the wretched YELLOW KEY.
 

MAP 27 - "MONSTER CONDO" - Sandy Petersen
Yellow Key

From start go to the wooden door to the east. Go to the farthest south switch and use it. The YELLOW KEY pitifully waits for you like a misbehaved dog.

Blue Key

You need the YELLOW KEY, from the YELLOW KEY exit the "library" and go through the door on the north side of the acid pit. Flip the metal switch on the west wall. Go through the door and through the YELLOW Door. The BLUE KEY will be waiting for you.
 
Red Key After you get the BLUE KEY, shoot the demon face on the northern wall to open the secret door and hot the switch behind it to open the door out. Go out through the south door and hit the switch to raise the stairs. Go out the door at the top of the stairs and head east to the blue door. Open the blue door and hit the switch. Behind you will be the RED KEY.
 

MAP 28 - "THE SPIRIT WORLD" - Sandy Petersen
Yellow Key

From the start take the east hallway to the ledge. Go through the central "lobe" and to the bloodfalls just to the east (left) of the two grey and yellow pillars. Go down the falls and head south to a huge red room. Run through the blood to a doorway on the wall behind the central pillar (an Invulnerability Sphere would be a good idea) and go up the stairs to a room with a raised dias, six pillars and a thrown. Sit on the thrown to lower the dias. Get on the dias and hit the two (almost) hidden switches on the walls after the dias raises. A door will open in the northwest corner. The YELLOW KEY will be sitting there like roadkill.
 
Red Key

From the YELLOW KEY go back to start and open the yellow door. There will be the RED KEY.
Blue Key The spirit of this level is forever damned for it's failure to display the awesome beauty of the BLUE KEY.

MAP 29 - "THE LIVING END" - John Romero
No Keys There are no keys on this map.

MAP 30 - "ICON OF SIN" - Sandy Petersen
No Keys This map is so evil it does not need any damned keys!

MAP 31 - "WOLFENSTEIN" - Sandy Petersen (NOT IN THE "GERMAN VERSION" OF DOOM2)
No Keys Nope, no keys on this map.

MAP 32 - "GROSSE" - Sandy Petersen (NOT IN THE "GERMAN VERSION" OF DOOM2)
No Keys No keys on this map, either.!