MAP57: The Marshes (PlayStation Doom)

MAP57: The Marshes is a secret map that appears in the PlayStation and Saturn versions of Doom, which can be accessed from MAP29: Twilight Descends. It uses the music track "Corrupted" by Aubrey Hodges. It was designed by Randy Estrella.

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.

Secrets
1. In the area with the rocket launcher and the 10 rocket boxes there are 4 openings one of which has a small bridge leading to a small area containing a megasphere.

2. In the megasphere area there is a skull on the wall. Flip it, walk through and you will be teleported to a small cave containing a BFG 9000.

Trivia
This is the only time in any port of Ultimate Doom level that one will find a Super Shotgun.