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 will be discovered 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
The player begins in a dark room in the southwest part of the map. A small canal leads to a wide open area ("A", Fig. 1)

Part 2: South castle interior
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.