MAP13: 2400 Fulton Street (Eternal Doom IV)

Map 13: 2400 Fulton Street is the sixth map of the 7-map PWAD Eternal Doom IV: Return from Oblivion. Designed by Chris Couleur, who also did Map 11 and 12, Map 13 is a huge, sprawling map with 6 keys and 7 secrets to discover, and about 1000 enemies to kill, notably several cyberdemons. Many of the enemies are spawned, sometimes silently. The player's inventory from the previous map is not carried over. Only a pistol is available at the start, but all other weapons can be found in the map. The player must also obtain 13 artifact items in order to achieve 100% items.

In terms of the map's architectural designs, there is a nice mixture of elegant medieval structures, rough outdoor terrains, as well as dark castle interiors and swampy areas. Per the map designer, jumping is disabled by default for this map, unlike other maps in the WAD.

Walkthrough
The map is divided into several regions, which the player must unlock one by one with keys or triggers. Every unlocked region invariably contains a key that unlocks the next region. Like other maps in the WAD, there is a "hub" area that connects several regions together, provided that all paths are cleared with the proper keys or triggers.

Part 1: SW and SE regions
You begin in a dark room in the southwest part of the map. A small canal leads you to a wide open area ("A", Fig. 1a), where a shootout lasting several minutes ensues. A small room (B) is accessible by swimming underwater or walking on the ledges above. An underwater passage leads you to a smaller pool, where you find a blue key card and a soul sphere (item 1 of 13).

Head east and use the blue key card to unlock the door that leads to a small lake with several small islands. Dispatch any enemies close by. At one corner of the lake, there is a hard-to-see underwater passage. It leads you to a castle area at southeast (C).

A pool is in the middle of this area, surrounded by grey stone structures. This area has an intricate sequence of switches to activate. On the landing beside the pool, a face switch (C1, Fig. 1b) opens up staircases that lead to the upper levels. Go up the stairs to the second level and kill all enemies in your way. There is a dead marine in a small room behind bars. To pick up the health bonus behind bars (item 2 of 13), run towards the bars and bump against them repeatedly, and eventually you will grab the health bonus.

Shoot the dead marine behind bars (coup de grace?) and a nearby wall (C3) will open up and a few mancubi will spawn. Kill them, and go to the balcony (C3), where another face switch opens a staircase that takes you up another level. Go up to the third level. The end of the corridor is a door that opens to a room with a rocket launcher on top of a pillar.

At one corner (C4) of this room, a face switch lowers the rocket launcher, but also opens up a room (C5) from where a few hell knights and barons of hell emerge. This room also has a teleporter that takes you to the tall pillar (C6) in the middle of the pool.

There are two switches on the pillar. One opens a small space (C8) in the previous room, and the other opens up a wall nearby that reveals an arachnotron. You jump down from the pillar to give yourself more room to fight the monsters. At one corner on the second level, there is a face switch (C7) that opens up a secret room (secret 1 of 7) inside a wall, where a revenant and a few powerups are revealed.

Go up to the third level again and go to the newly revealed face switches at C8. One of them lowers a platform (C9) that reveals a room (secret 2 of 7). An arch-vile spawns right next to you. You go back to C8 and flip the other switch. A nearby wall opens (C10), revealing a passage that takes you to a room with another tall pillar at the center.

After the ensuing shootout, go down a long corridor (C11) and flip the switch there. It raises a staircase that takes you to another switch (C12). Flipping that switch reveals another switch (C13) on the other side of the wall and also opens up a room (C14) next to two deep pits. There are two cacodemons in those pits that you can't see due to your inability to jump. They don't hear you either. You need to fire rockets down there, so the splash damage will make the cacodemons come up. After killing them, return to C13 and flip the switch, which raises a staircase that lets you get to the top of the pillar. Three of the switches at the pillar spawn monster, while the last one opens a door below that leads to an outdoor area (D).

Part 2: South wing
After entering the castle interior with the red skull key, the door closes and can't be opened again until the player unlocks it with a yellow key card, which the player will find in this region.

Part 3: NE region
After exiting the south castle, the player needs to go north and unlock the NW region with the yellow key card.

Part 4: NW region
With the red skull key, the player enters the most challenging region in the map, the northwest.

Part 5: NW courtyard
The NW courtyard is like a hub that connects to several regions of the map.

Part 6: Final Stages
The yellow skull key allows the player back to the SW region to fight the cyberdemons and exit the map.