Doom Episode 2 Walkthrough

After escaping through the interdimensional portal in the Phobos Anomaly by the skin of your teeth, your character arrives at a scene that's familiar...yet disturbing. It's the lost UAC techbase on Deimos...and it no longer orbits above Mars. It's now in a far more sinister place.

In contrast to the terraformed mountains of Phobos in Episode 1, the Deimos landscape is utterly barren. The techbase facilities still stand, but most have been vandalized...and modified with malevolent elements. The overall effect is a mindscrew.

This walkthrough is focused on the objective of exploring all areas. Throughout the page, ▶ points to "official" secrets counted in the end-of-level tally, and ▶ points to other hidden areas.

E2M1: Deimos Anomaly

You begin the episode at the entrance to a small building on the outskirts of the UAC property. Immediately, you'll sense that things are amiss: A teleport surrounded by candles stands in the first corner of the corridor, followed by a portal in the shape of an inverted cross. At the end of the corridor, you'll find an observation area holding the [Blue key] blue key. Backtrack, and take the teleport: You're now in the very area you were overlooking earlier. Cross over the pit of blood, and hit the switch on the wall: A panel will rise out of the floor with switches on both sides. Hit the switch on the outer face to open a teleport in the blue key area you were in earlier. 1 ▶ Hit the hard-to-see switch on the inner face to open a hidden compartment in a nearby wall, containing the [Blue key] red key.

2 ▶ The teleport in the blue key area requires quite a bit of backtracking to get to, but will take you to a darkened room with a plasma gun...and quite a few enemies. Take the teleport next to the red key area. It'll transport you to a corridor finished in green stone, with two skull switches in a niche. The right switch lowers a wall in the corridor, while the left switch opens a panel in the wall with yet another teleport. 3 ▶ Follow the teleport, and it'll take you to a secret corridor with bonuses galore. ⚠ The switch that accesses this secret only works once.

With the corridor wall out of the way, you now have access to two keyed doors. The [Red door] red door takes you to a bonus area with megaarmour and a computer area map. The [Blue door] blue door gives access to a teleport leading to a room with a switch on the wall. Hit the switch, and a staircase will rise into position. Hit the second switch at the top of the stairs, and a teleport will lower. Take the teleport, and you'll arrive at the exit.

Depending on your difficulty level, either Lost Souls or Cacodemons will make their first appearance on this level. E2M1 is also the first of Doom's levels to contain a Plasma Gun. The red key is not necessary for completion.

Gallery

The inverted cross that greets players after they emerge in the Deimos Anomaly.

The plasma gun makes its first appearance in this level.

"Deimos Anomaly," the entrypoint of the episode depicted on the intermission screen.

E2M2: Containment Area

"Containment Area" is a large level with a layout split between a north crate storage area, and a south area with Hell-corrupted lifts, crushers, and toxic pools. The map was created by Tom Hall, and early versions appeared in development alphas as early as February 1993. Today it might be the single most iconic level of Doom, with its crate maze in particular often referenced and memed.

You begin near the northwest corner, facing down hundreds of crates in your path. ▶ There's a switch on the left wall ahead: Pull it, and a crate will lower behind you revealing some shotgun shells.

You could easily spend ten minutes or more simply exploring the maze: There are numerous health, armour, and ammunition bonuses to be found, as well as shortcuts where you can climb over crates. One item you should be sure to pick up is the Berserk pack: It's stashed in an inner corner, just around the bend from your starting position. 1 ▶ There's also a crate wedged against the west wall. If you "open" it from the north, it will lower into the floor and reveal more shotgun shells for the taking. Since it's easy to get disoriented in these surroundings, remember that your automap is a short tab away.

The central hall may be accessed from either the west or centre sections of the crate maze. Walk to the hub, go past the candelabras decorating the south portal, and hit the skull switch on the side wall. A door will open, and a staircase will rise...and although the door itself still bears the UAC logo, what lies beyond is a cacophony of elements from the nether world.

Turn left at the illuminated pillar, then turn left again. You're faced with your first Hell-spawned puzzle. To pick up the [Yellow key] yellow key without getting hurt, follow the pattern of circles on the ceiling. A series of platforms will rise, keeping your toes dry from the blood.

Now, it's time to explore! ▶ ▶ ▶ Ahead of you are three uncontrolled sets of moving columns with items hidden behind. Stick to the wall, and you'll be able to pick them up without issue. 2 ▶ The nearest set of columns hides an underground passageway with numerous health bonuses within, and an exit point that drops you back in the central corridor.

Return to the illuminated pillar, turn right, and turn right again. You'll cross three linear chambers with electrified floors. 3 ▶ At the end of the last chamber, you'll see a dark passageway in the corner. Follow it to a backpack. ▶ When you pick up the backpack, a wall will open revealing an ambush. 4 ▶ Open the back wall of the ambush area. It's a hidden door, revealing an egg-shaped room with a few more enemies and bonus items within. ▶ Look for a misaligned panel on the wall. It's yet another door, revealing a winding passage. 5 ▶ Look for a panel on the wall with an embossed "X." It's yet another door, revealing a computer area map. Continue down the winding passage: It will end at a door opening to the central hub.

Now it's time to head back to the crate maze. Follow the central portal straight ahead, turn left where you found the Berserk pack, and go through the door just left of it. It opens to an outer ring around an inner room protected by a [yellow door] yellow door. 6 ▶ Go inside, and hit the switch on the wall: The pillar will lower, the toxic pool will drain, and a chaingun will be there to add to your arsenal. (Collect the gun or touch the square it's on to register this secret.)

Return to the crate maze, and work your way to the northeast corner. Another [yellow door] yellow door awaits you there. Open it, then RUN to the backpack near the opposite wall! Three switches will rise out of the floor, each of which opens a storage closet in the adjacent room. 7,8,9 ▶ Blast the enemies away, then check the closets for a free rocket launcher and other items. Each closet registers as its own secret area. Entering them also causes the switches to retreat back into the floor...so if you missed the backpack the first time, you can pick it up now.

You've finished exploring the north portion of the level. Head back to the south side, turn right at the illuminated pillar, and follow the corridor until it ends: You'll find a room with bullets and megaarmour. Follow the right wall to a corridor with a raised brown floor, and turn left into the room with hexagonal tiles: 10 ▶ The steel pillar has a switch on the inner face that lowers a pillar with a plasma gun. (Collect the gun or touch the pillar it's on to register this secret.) ⚠ This switch only works once.

Continue down the corridor with the brown floor. You'll see a side room with some armour, and a moat of toxic waste separating you from the exit. (Try not to fall in...but if you do, you can follow it to the central corridor and scoop up two radiation shielding suits along the way.) You'll have to run a gauntlet of five crushing pillars. Be careful! 11 ▶ Duck left under the third pillar, and you'll find a secret room with a chainsaw. The corridor turns left after the crushers, and leads to a toxic pool. 12 ▶ Standing on the bright spot in the southeast corner of this area triggers a hidden switch that opens a compartment in the north wall with a soul sphere within. ⚠ But be fast: This trigger only works once!

Collect the [blue key] blue key from the far edge of the toxic pool. Just behind it is a winding staircase leading to a [blue door] blue door, opening to the central corridor. Another blue door at the end of the corridor gives access to the [red key] red key. (On Doom 1.1, this door is controlled by a switch on the observation platform overlooking it.) You now finally have everything you need to finish the level. Return to the toxic moat area where the crushers begin, go through the [Red door] red door, and operate the switch inside. A platform will rise, leading to the exit.

Other than retexturing, the most significant change made to this level in post-alpha development was its flow: Originally, the player was intended to enter the map at the west end of the central corridor and exit it at the east end. The yellow key is not necessary to complete this level of the game.

Gallery

February 1993 alpha map. Much of the south half of the map is unfinished. The player enters at the west end of the central corridor, and an implied exit is at the east end. The central lobby is very large, and features a reception desk.

April 1993 alpha map. Details have been added to the two north rooms, and the lobby has been downsized.

Detail from May 1993 intermission screen, designating the level as a "supply depot" with an entrance at each end. A comment elsewhere on the map notes that the building's perspective is off.

May 1993 alpha map, with the south half of the map fleshed out to close to its final form.

October 1993 pre-beta map with the entrance and exit relocated away from the corridor, the crate maze broken up with pass-throughs, and a toxic waste trench added. Close to the final version, apart from a relocated door.

The iconic maze area of E2M2, with crates of all sizes.

The Berserk pack makes its first appearance in this level.

The yellow key puzzle, where the player avoids a pit of blood by following the pattern on the ceiling.

"Containment Area," as depicted on the intermission screen in the final game.

E2M3: Refinery

The Refinery is in rather decrepit condition. You begin in a corridor overgrown by weeds. The door at right leads to a room with broken wall-mounted equipment, a radiation shielding suit, and a chaingun. Continue down the corridor to the outdoor area with bars on the windows: You'll encounter your first Cacodemon here (on most difficulty levels), and there's an invisibility sphere just behind.

There are two passages before you, both of them overgrown. Follow the left passage until you see faces on the walls, then turn around: 1 ▶ The panel in the corner is a hidden door, with a backpack within. Afterward, venture forth between the faces: There's a Hell-spawned construct with twelve rising pillars, hollowed out of rock and surfaced in flesh. 2 ▶ In the near left corner, there's a hidden one-way door serving a shortcut to an oval-shaped room with megaarmour. Go this way: Otherwise, you'll have to wade through toxic waste at the other end of the passage. 3 ▶ The oval room has a second one-way door on the left, letting you return to the corridor you were in before.

Head out of the room, past the glowing platform with the shotgun: You'll find yourself in a green marble corridor. 4 ▶ Follow the passage to the left until you reach a red blood pool, then jump in: There's a staircase leading out, with a plasma gun and other items. It leads to a room where you'll find the [blue key] blue key.

Backtrack to the oval room, following the semi-hidden way out that you discovered earlier. Follow the corridor around the corner: The [blue door] blue door will be on the right. Note that the frames are decorated in skulls, instead of rectangular tiles: It's a taste of things to come.

Follow the dark passageway past the flickering lights. It leads to an open room with an invisibility sphere, followed by a seizure-inducing maze of vertical pillars. Follow the right wall, and you'll emerge at the edge of a chamber filled with toxic waste. 5 ▶ Take a right past the vertical dividers, take a hard right, and you'll find an alcove in the corner with a radiation shielding suit. ▶ On the east face of the chamber, there's an opening leading to a room with bonus items. 6 ▶ This room also has a soul sphere hidden on a platform in an alcove.

Find your way to the landing at the other edge of the toxic waste, and follow the corridor to the exit.

"Refinery" was created by Tom Hall and was one of the first maps drawn for the game, existing in development as early as February 1993. Early versions of the level featured a near-triangular footprint, still evidenced in the final version by the "dead" north corners of the map.

Gallery

February 1993 alpha map, contained within a nearly-triangular footprint. The April 1993 version is virtually identical. Documentation and graphics reveal that this level was originally intended to feature one-way conveyor belts, although these were never implemented in Doom.

Detail from May 1993 intermission screen, designating this level as a "waste processing facility" and retaining the triangular footprint.

May 1993 alpha map, with many of the areas in the west and northeast portions of the level enlarged. The final version is almost identical.

The flesh-covered pillars, easily one of the more revolting images from the game.

"Refinery," as depicted on the intermission screen in the final game. It barely stands out on the map.

E2M4: Deimos Lab

"Deimos Lab" appears to have originally been intended as the secret level of Episode 1, occupying this slot in the May 1993 alpha release. When the level order was shuffled later in development due to creative changes and a reduction in maps per episode, it was repositioned as a main level in Episode 2. As with most of Episode 2's levels, it was created by Tom Hall and tweaked (with the addition of teleports, in this case) by Sandy Petersen.

You start in a dark room. 1 ▶ Look for a panel on the right wall, illuminated by a flickering light: It's a hidden door leading to a shotgun and a few other items. Take the teleport ahead of you. It leads to a hall surfaced in hexagonal tiles. Take the lift on the back wall, and follow the stairs to a cage full of items, including a computer area map. ▶ The cage will release itself if you stand next to the skull idol on the right. 2 ▶ A door behind will also open, containing some enemies and ammunition. This counts as a secret sector.

Retreat back to the hall, and take the corridor branching off to the right. It crosses a ring-shaped channel of toxic waste. Take the first right after it, enter the Hell-corrupted computer room, hit the skull switch on the back wall...and look out for the crusher! 3 ▶ On your way out, shoot the wall in the recess. A door will open, revealing a room with an invisibility sphere and chaingun.

Return to the corridor you were on earlier, and head right. Along the way, you'll see a ghoulish face with horns carved into a wall: This is a warning sign that on higher difficulty levels, a Baron of Hell is going to be around the corner. Go through the door at the end of the corridor, and fight. Hit the switch, take the lift to the [blue key] blue key, hit the second switch, and follow the elevated passageway. You'll pass some ceiling crushers (be careful!), and a side passage with a few stimpacks. Eventually you'll reach a chasm bridged by a thin, squiggled walkway. Collect the radiation shielding suit, then turn around: You'll see a Berserk pack in the left half of the chasm. 4 ▶ Drop down to collect it, then follow the passage to the ring-shaped toxic waste channel. ▶ Although the main corridor is just to the right, go left and follow the ring the long way around to the north side: You'll find a ledge with armour and an invisibility sphere. 5 ▶ You'll also have triggered a hidden door on the facing wall with health bonuses, medikits, a soul sphere, and a radiation shielding suit.

Find your way back to the main corridor, retrace your steps west, and take the right fork at the ghoulish face. Collect the backpack and health bonuses at the centre of the room's spiral, then head through the [blue door] blue door. It opens into a room bathed in red light. Collect the [yellow key] yellow key from the platform, but be quick about it: ⚠ The ceiling will crush you when you step on to get it!

Head to the [yellow door] yellow door elsewhere in the same room. It opens to a perimeter walkway around a massive circular enclosure. Hang a left, and follow the walkway until you see a tan passage to the left. It leads to a room with a lava pool and five doors. Open the centre door first, and walk to the back wall: Two adjacent doors will open, unleashing pink demons. 6 ▶ The right door leads to a toxic pool with an alcove to the side hiding a megaarmour. It also contains a trigger for the left door, which opens to a passageway leading to 7 ▶ an overgrown chamber with bonus items. ⚠ Be very quick entering this chamber: A barrier will rise from the floor, crushing you if you don't clear it in time. ▶ Once you make it in, open the green panel on the wall for an escape route back to the passage.

It should be stressed that the aforementioned part of the level is not required for completion...so if you're in a hurry, feel free to skip it. You can also collect the ending bonuses while bypassing the five doors altogether: Head into the lava pool. 8 ▶ In the near left corner, there's a hidden platform with two medikits. (Stepping onto it is necessary to trigger the secret sector.) ▶ Now head across to the alcove with the rocket, and open the back wall: It's a shortcut that leads directly to the left door's corridor.

Go back to the perimeter walkway, turn left, and look for a slight indentation in the outer wall. ▶ This is a pit. Fall in. 9 ▶ Feel the wall: A hidden door will open, revealing a plasma gun and a teleport to an elevated control area in the centre of the circular structure. Take the landings down to the surrounding floor. (If you'd like to go back up again, there are three switches along the way that convert the landings to a handy set of stairs.) To return to the rest of the level, there is a flesh- and bone-surfaced lift on the north side. It is controlled by a switch in a small room to the left.

Now it's time to finish the level. On the south end of the circular enclosure, there's an alcove leading to a teleport. This transports you to a room where the faces of tortured souls scroll behind bars. Follow the passage to a pit of blood, then jump in and head to a platform in the left corner that straddles a wall switch and a teleport. Before you use the teleport, turn around and hit the switch: This raises a platform in the room. Take the teleport back to the circular structure, turn around, teleport again, and return to the newly-bridged pit. 10 ▶ Cross the bridge to the exit portal, then turn around: A second bridge will rise, letting you collect a soul sphere hidden on the back wall.

Gallery

Detail from May 1993 intermission screen, designating this level as a "laboratory" on the restricted side of the techbase.

May 1993 alpha map, very similar to the final version aside from the lack of teleports at the entry and exit areas. The final version also contains two additional secrets, and two rooms on the north face of the circular structure.

The squiggled walkway over the chasm at the south end of the map.

Like Phobos Lab in Episode 1, "Deimos Lab" is depicted on the intermission screen of the final game as having a central hub and four wings. This doesn't even remotely resemble the geometry of the actual level.

E2M5: Command Center

Command Center is the first level in sequence developed entirely by Sandy Petersen, reflecting his gothic horror sensibilities. It offers multiple paths to completion, although quite a bit of backtracking is required to explore all areas. Surprisingly, it has no keys.

Open the wooden door, and enter the room with pink demons in the upper gallery. 1 ▶ To the left, you'll find a secret area tucked into a jog on the east wall...simply approaching it will cause the door to open. 2 ▶ There's a companion secret area on the opposite side.

In the north corners, you'll find a pair of staircases leading to the elevated gallery and an area with skull switch-controlled doors. Open the central door: It leads to a dirt-enveloped room with a wide door within, concealing a backpack and Berserk pack. Next, take the exposed stairs to the outdoor area, where you'll find a chaingun and computer area map. Behind the hell baron picture is a skull door leading to a wood-panelled room. 3 ▶ Turn left, go through the door, and look for a misaligned panel in the left corner. It hides a chainsaw.

There's another door on the opposite end of the room...but we have other areas to explore first. Go back outside: The outdoor area is bounded by pools of toxic waste. ▶ Jump into the right pool, and there's a switch-operated lift in the corner leading you to a side room with armour (also accessible from the gallery level). ▶ Jump into the left pool, and there's a matching lift that leads to a narrow stairway. Both lifts are concealed from the interior by doors accessible from the pool side only.

Follow the staircase down. It leads to a winding passageway that ends at a skull door. Go through: You'll come out in a green marble room with candelabras surrounding a light amplification visor. Now, you have a choice of where to go next:

Exploring the level, and finding the regular exit

Follow the passage south to a room with three columns and a ghoulish baron face on the wall (that hurts you if you stand too close to it!) Facing the columns, you'll see two skull doors to the left and two skull doors to the right. The left doors lead to a loop-shaped passageway with an invisibility sphere, while the right doors open to an overgrown walkway that runs alongside a toxic underground river. Follow the path to the point where it loops, and hit the switch on the wall. The panel will open, revealing an inner room with a second switch. ▶ Hit this switch: It raises a platform elsewhere in the level.

Retreat back to the room with the columns. To the right of the baron face is a fifth skull door: This leads to the wood-panelled area near where you found the chainsaw. Go this way, go through the skull door on the opposite side, then take the spiral staircase up. 4 ▶ When you reach the top landing, you'll hear a door open in the distance. Run back to the bottom and you'll find that a hidden door has opened, revealing a pink demon and a radiation shielding suit. Back at the top, you'll find two skull doors, one leading to a room of zombies and one leading to a subterranean staircase.

The staircase splits into two forks. The right fork leads to a long passageway covered in toxic waste. (Good thing you grabbed that radsuit!) Stick to the left wall: After you wade past the walkway you were on earlier, you should see a wall panel rise in the north wall, revealing another long muck-covered passage. 5 ▶ Follow this out to a platform where you'll find a nasty surprise: A Baron of Hell in a cage! Just beyond is a bright room with three doors. The door with the baron portrait leads to a plasma gun and energy cell pack (by way of the switch-operated platform that you raised earlier), while the outer doors lead to an outdoor ledge with armour bonuses. 6 ▶ Fall into the toxic pool below, and head right to pick up an energy cell pack. This counts as another secret. Then, head to the opposite end of the pool to teleport back to the beginning of the level.

Retrace your steps to the subterranean staircase you were on earlier...and this time, take the left fork. It leads to a dark wood-panelled room with candelabras. Grab the radiation shielding suit, head through the skull door over the toxic waste, climb the stairs, and come out through the door at the end. You're in a revolting room surfaced in flesh. Proceed through the skull door on the other side, and follow the passageway until it forks. A room with armour will be ahead...although an ambush of pink demons will be unleashed when you collect it. The left and right forks of the passage loop around, and lead you to the exit.

But that's the regular exit. You wanted the secret exit, didn't you? Welp, time to backtrack again...

Secret exit

In the green marble room with candelabras, there are two skull doors...and so far, you've only been through one of them. ▶ Go through the door on the left, and hit the switch on the wall: 7 ▶ A staircase will rise, leading to a concealed teleport. 8 ▶ This transports you to a circular room with red lights overhead. 9 ▶ Hit the face on the wall and a door will open, leading to a silver teleport. 10 ▶ This transports you to a room containing the portal to the secret exit.

Gallery

Portal leading to the secret level.

"Command Center," as depicted on the intermission screen. Looks like a Bundt pan, doesn't it?

E2M9: Fortress of Mystery

You begin in an eight-pointed room hewn from rock. You won't have much time to take in the scenery, though: There are four Barons of Hell on the floor, as well as several Cacodemon corpses serving as an ominous warning. You're next.

You could simply blast the Barons away at the outset with a plasma gun or rockets. A more challenging and satisfying way to complete the level, however, is to encourage infighting. Open the door in the east wing (due right of your starting position), which leads to a cross-shaped marble room filled with Cacodemons. Lure the Barons in and run about the room in circles, avoiding clusters of enemies. Eventually the Barons and Cacodemons will start killing each other until only a few are left.

The eight-pointed room has five weapons, an ammunition backpack, and a computer area map waiting in its wings. The cross-shaped room contains a soul sphere and numerous pick-ups. It may be worthwhile to grab some or all of these before starting your fight, but try not to get cornered.

1 ▶ The way out of the cross is through a hidden door located between the faces on the east wall. This leads to a small room with numerous doors. Hit the skull switch to retrieve the [blue key] blue key, open the [blue door] blue door to retrieve the [red key] red key, open the [red door] red door to retrieve the [yellow key] yellow key, and open the [yellow door] yellow door to reveal the teleport serving as the exit. This is the first level of Doom in which you'll encounter skull-shaped keys...and as with other hellish developments in Episode 2, they're a taste of what's to come.

Gallery

Barons of Hell and Cacodemons making mincemeat of each other.

"Fortress of Mystery," as depicted on the intermission screen. The fortress only appears on the map if the player enters the level.

E2M6: Halls of the Damned

Proceed forward from your starting point, collecting the rocket launcher. Go through the door to the Hell-corrupted room, push the switch, and backtrack to your starting position. The right wall will have opened up, revealing a looped passageway leading to an outdoor area with vertical pillars and streams of toxic waste. Hit the switch on the opposite wall: A platform will rise, letting you nab the Berserk pack. In turn, a door behind you will open, and the platform between the toxic streams will sink away.

Run down the toxic waste-covered passageway (there are medikits, if it's any condolence), and hit the switch at the end, and come back. Yet another hidden door has opened, this time in the looped passage you came in on. The alcove contains a blue exit door and a side door.

Open the side door, and follow the passage left until you collect the [blue key] blue key. An ambush door will open on the facing wall. ▶ Open the brown wall panel behind, and you'll find a chainsaw.

You're going to need three keys to finish the level...and two of them are buried deep in the complex. Follow the left wall to a switch, hit the switch, then continue down the brightly-lit passage until you see the entrance to a dark, wood-panelled area at left. Bear towards the flashing light where you see three skulls on the wall, then look for a face on the wall beyond: There's an opening here leading to another section of the room, which in turn leads to an illuminated door. Go through the door to a steel-panelled room, then feel the right wall: You'll find an alcove with a light amplification visor. The [red key] red key is also in an alcove, straight out and slightly left from the last. If you're feeling adventurous you can also look for a plasma gun in the east section of the room, and there's an ambush room containing an invisibility sphere.

Head back to the brightly-lit passageway, and take a left: You'll see three side doors next to candelabras. The first of these leads to a UAC computer room with another light amplification visor. The second and third loop together, and end at a switch and No Trespassing sign. Hit the switch and a panel will open, revealing a passageway leading to a hub with doors on four sides.

Hang right, and take the south door: It leads to an overgrown area with pink demons, an invisibility sphere, a third light amplification visor, and the [yellow key] yellow key. As you head out, note the unusual frame on the door: It's actually a one-sided keyed door, requiring the yellow key from the inner face only.

When you return to the central hub, three ambush doors will have opened, resulting in a horde of imps to fend off. None of the other branches of the hub are required for level completion...but they're fun to explore at least once, and they count as secrets. 1 ▶ Take a right down the east passage, which opens at a [yellow door] yellow door leading to an "exit." Things are not as they seem, though: When you hit the switch, the floor will lower into a red room with enemies galore. It's not all bad, though: There's a soul sphere to collect, plus a computer area map in the passageway beyond, which loops back to just aft of the "exit."

2 ▶ The north passage leads to another hub-like room with bonus items on a central platform. If you think this reeks of a trap, you're right: Four closets will open, and Lost Souls will swarm in.

3 ▶ The west passage leads to an overgrown room. ⚠ As you enter, a back wall will open and a crushing ceiling will be activated. There's also a chaingun here, and a switch that triggers the door.

When you've had enough, follow the southwest fork back to the brightly-lit passageway, and find your way to the [blue door] blue door you saw in the early stages of the level. ▶ Two side rooms will have opened along the way, with a few items and enemies. The blue door will be followed by a [red door] red door, then a [yellow door] yellow door, then the (actual) exit.

Gallery

"Halls of the Damned," as depicted on the intermission screen.

E2M7: Spawning Vats

In a historical context, "Spawning Vats" might be the most significant level of Doom. In the earliest development alphas it appeared as a starting level, "Hangar Two." It's reputed to have been the very first level drawn. In the finished game, this map serves as the final UAC construct that the player traverses, and the final level in which UAC keycards are seen. Typical for levels by Tom Hall, it features a regular footprint with realistic environs and high density.

You enter the level through a rough-hewn room that appears to have been carved out of rock. Take the left door ahead of you, and follow the passage to a room with rounded corners. The door at right leads to a supercomputer and megaarmour; the door ahead leads through a series of rooms to a warehouse. The warehouse contains a Berserk pack and invulnerability sphere, both of which are handy for fending off the demons that spawn in this space. It's also one of the few places in the finished game where you'll see the "grey with maroon stripe" wall texture that was ubiquitous as a placeholder in the early alphas.

Hit the switch on the south door to retract a barrier, and follow the passage to an open-air area with vertical columns between pits of toxic waste. In early alphas this room was the level's titular hangar, and featured a central track and massive doors on the south end. The [Blue key] blue key now occupies the same place. Pick it up, then hit the recessed switch to the left in the southeast corner. A door on the west wall will open, granting access to an energy cell pack and bonuses.

In the passageway connecting the warehouse to the former hangar, there's a recessed staircase leading to an observation and control area. Follow the steps, walk to the far end, and take a 180-degree turn to the left: You'll see a staircase leading down to a switch. Hit the switch, and turn around: 1 ▶ A secret door will open, revealing an invisibility sphere and a computer area map.

You're finished with the east portion of the level. Backtrack through the warehouse to the room you started in, then proceed through the wide, dark doorway you bypassed earlier. It leads to a room with a blue door (we'll come back to it in a moment), and a baron portrait ominously warning of dangers ahead.

Continue down the passageway to the room with cylindrical UAC tanks built into the walls. Sure enough, a Baron of Hell will be standing at the end of the corridor waiting to have his way with you! Run to get the invulnerability sphere (and other handy bonuses), and take him down. 2 ▶ In the middle of the south side of the corridor, you'll find a hidden passage tucked between two tanks. Follow it to a dim, open-air area with a plasma gun and armour. 3 ▶ On the north end of this area you'll find a switch that opens a hidden compartment just behind, with a chainsaw.

Backtrack to the [Blue door] blue door. It opens to a staircase, with a chaingun at the top. A passageway extends to the left, forking in two a short distance down the stairs. Bear towards the right wall at the fork, and follow the ascending staircase to an elevated room with torches and a toxic pit. Hit the switch on the wall (it's one of two that need to be operated to access a secret in the starting area), then take one of the two doors that flank it to access a stage-like area with an ammunition backpack. Head back down the stairs, and turn right when you reach the fork again. It leads to the [Yellow key] yellow key. Take it, then drop down into the room below. You're now in the central area of the level, with numerous rooms to explore. Take a left out the back door, hang a left again, and you'll find a computer room with a few items within. Step onto the elevated area at the end of the corridor, and you'll see computer screens bearing the original setting name, "Tei Tenga."

Head through the [Yellow door] yellow door on the south wall: It leads to another corridor, with two rooms on each side to explore. Be careful of the track in the middle of the corridor: It carries an electric charge, and will shock you! The first room on the left was the starting point of the game in the earliest incarnations of this level. The last room on the right features a brushed stainless steel console with a passageway underneath that leads to a switch. Hit this switch, and the [Red key] red key will be lowered in the centre of the room.

You now have almost everything you need. Follow the corridors left, then left, then left again until you see a door with horizontal ridges next to a blue torch. Go through the door, then pass through the exit area to a Hell-corrupted room with glowing red walls. To the left, you'll see a doorway flanked by "Radiation" signs guarding a series of square radioactive waste vats within. 4 ▶ Behind one of the vats is a visible passageway leading to a room with a rocket launcher and teleport. 5 ▶ Take the teleport to the red room, open the [Red door] red door behind it, and flip the switch. 6 ▶ Now, go back to the room you started in: A hidden door has opened, revealing an energy cell pack and soul sphere.

Time to bring this level to a close. Go back to the room with the exit portal, open the [Red door] red door on the north wall, and hit the switch. The switch will retract, revealing a second switch, and a door will open releasing a Cacodemon into the adjacent room. Hit the second switch, and a platform will rise granting access to the exit.

Gallery

Tom Hall's November 1992 drawing of "Secondary Hangar," the proposed first level of the game. Aside from having intersecting corridors, it scarcely resembles the later maps.

February 1993 alpha map. Note the exit portal in the northeast corner and the central track running through the hangar bay in the southeast, both of which were later excised from the map.

April 1993 alpha map, still occupying its original slot as E1M1. The warehouse and hangar bay have been reduced in size, several rooms on the south side have been reshaped, and an extensive network of hidden staircases have been added to the north half of the map.

Detail from May 1993 intermission screen, prominently showing the hangar doors and an extension of the track extending outside from the southeast corner.

May 1993 alpha map, with several additional rooms added but still notably lacking the exit portal of the final map.

The invulnerability sphere makes its first appearance in this level twice over.

Computer screens in the level show the name "Tei Tenga," Tom Hall's original setting for the game.

"Spawning Vats," as depicted on the intermission screen in the final game. It resembles a rock salt storage dome.

E2M8: Tower of Babel

The level begins with the player facing off in a four-sided chamber. Dead Barons hang in the niches, and a four-sided cluster of switches stands in the centre. Push each switch: A small staircase will rise into position, allowing you to exit the chamber by walking towards a niche, causing a one-way door to automatically rise. You may wish to approach and back away from several of the doors, just to choose which route to take: Two open up to rooms with soul spheres, one opens up to a room with a rocket launcher, and one opens up to a bulk load of rockets.

Whichever route you take, you'll soon be outside. Remember the green marble baron portraits in past levels, warning of dangers to come? There are dozens of baron portraits emblazoned on marble columns in this courtyard. Combined with the foreboding boss-arena architecture, you have a heightened sense that you're about to face a grave threat. Very soon.

Eventually you should hear a growl, and your adversary of the entire episode will spring into view: The Cyberdemon, an absolutely hideous demonic beast with ingrown horns, a mechanical leg, and gruesome entrails (or wires?) spilling out of its chest. It's the most difficult boss of the game. It will lob rockets at you, and a single hit can drain your health in an instant.

Your best strategy is to keep moving from side to side, strafing with the Alt key, hitting the Cyberdemon with waves of firepower from your plasma gun and rocket launcher, while pausing periodically to aim. Once you overcome this monster, the episode will automatically end. You realize that Deimos now literally floats over Hell...and the only way out is through.

Gallery

The Cyberdemon, as it appears a split-second before killing you.

An easy-to-miss detail of Doom's intermission screen is that the Tower of Babel is built in tandem with the player's progress throughout the episode, with new courses of stone added with every completed level.