MAP57: The Marshes (PlayStation Doom)

MAP57: The Marshes is a secret map in the PlayStation and Saturn versions, part of the games' Ultimate Doom episode, which can accessed from MAP29: Twilight Descends. It was designed by Randy Estrella. It uses the music track "Corrupted" in the PlayStation version, and the track "The Broken Ones" in the Sega Saturn port, both composed by Aubrey Hodges.

Walkthrough
Though this is a large, spread-out level containing a number of areas to explore, the main mission in this stage is to kill a Cyberdemon; doing so will unlock the exit in the beginning room.

Other points of interest
In the south part of the level, there are numerous trees forming a forest of sorts. If you carefully search within it, you will find a light amplification visor and a super shotgun - this is the only place where the normally Doom II-exclusive weapon can be found in the Ultimate Doom portion of the game.

There is a wooden building in the east portion of the level. If you walk up the stairs you can notice two skull buttons; both manipulate the light level of the outdoor portion of the map. Press the one on your right to increase the light level for better vision. The other switch makes the area darker, increasing the challenge of fighting the cyberdemon significantly.

In the watery area (the central area of the map), there are three groups of four teleporters. Never visit the ones in the south, as they always lead to an inescapable room with a slow crushing ceiling (though a BFG9000 and some cell ammo appear within it during deathmatch games, they only act as a lure for unsuspecting players).

Official
There are no official secrets in this level.

Non-official

 * 1) There is a building located on the central water pool. It is recognizable for its grey rock walls, number of imps and deep cyan lights in the room. There are two ways to get there: 1) use the group of teleporters which are located at the northwest of the pool. 2) Climb to the wooden building at the east of the map. Jump over to the wooden room separated from this building. Press the skull switch to lower the entire room of the aforementioned building you need to get into. Quickly get there. Collect the rocket launcher and ten rocket boxes. Beware the crushing ceiling ahead. Now notice the room has four openinngs. Face south and drop from the openinng on the bridge. Follow it to find a megasphere and a computer area map. If you press the skull switch here and try to jump off you will be teleported to another place facing a cave. In this cave you can find a BFG 9000.

Trivia

 * This is the only level in any port of Ultimate Doom where one can find a super shotgun.
 * The "re" trap area consists of designer Randy Estrella's initials, and exists as an easter egg which will usually only be noticed by viewing the automap.