Perdition's Gate

Perdition's Gate is a 32-level megawad for Doom II developed by Wraith Corporation and published by WizardWorks Software in 1996. The demo version, which contained the first 11 levels, was distributed via the Internet and on D!ZONE Gold discs. Unlike its sister release, Hell to Pay (a partial conversion containing new monsters, weapons, music, and textures), Perdition's Gate only contains new music and new graphics for various textures.

According to Tom Mustaine, Perdition's Gate was offered to Id Software. He contacted Shawn Green, who ''"responded positively about another 32 level pack for Final Doom." Shortly afterwards, he was informed that the "Final Doom window of opportunity had closed"'', so Perdition's Gate was offered to Wraith Corporation instead.

Story
Over 15,000 years ago, an alien race existed in a distant galaxy, a race of beings that had mastered ways of mixing technology with the power of the mind. These were the overseers of the universe, protectors of developing worlds, and masters of incredible technologies. Yet, possessing such technology led to conflicts with savage alien races, including a race of monstrous demonic aggressors.

A war ensued between the savage demon race and the alien overseers. The overseers attempted to make peace with the attacking force but their attempts ended in miserable failures. The savages were a race of pure evil, no understanding of diplomacy or peace. In a desperate final attempt at suppressing the aggressors, the overseers closed down their most valuable technology, the inter-dimensional teleporters. Before all the teleporters were powered down, legions of the demonic race made their way through, wreaking havoc on under-developed, formally protected worlds. One of those worlds was Earth, many thousands of years ago.

The sight of raging monstrous creatures to villagers and peasants in Earths biblical times bred fear in the minds of all. Eventually, the small unsupported armies of monsters were destroyed, but the advent of these creatures rooted myths into human culture about demons from hell and perdition. After the destruction of the initial demon force, myths and legends were all that remained regarding the existence of the creatures.

Thousands of years of evolution followed as the people of Earth began to forget about demonic myths and legends of the past while heading headstrong into the technological era. At the same time, the demons took over the former overseer’s world, and began their understanding of the overseer’s awesome technology. Masterminds were bred to help teach and integrate the demon technology with that of the overseers. Not until recently, did the demon race possess the power to re-commission the inter-dimensional teleporters. Thanks to the efforts of human experimentation on the moon of Phobos, the teleporters on the overseer’s world were given life once again. Soon after, the demon masterminds began to understand the workings of the overseer technology and started building attack forces to continue their conquest of the universe.

4 years have passed since Earth marine forces won the war against the demon aggressors. You are a cadet marine who has been called upon to serve in the UAC strike force while they continue running controlled gateway experiments at their Earth headquarters. Arriving at the main gate on your first day of service, you notice that things don’t seem to be running normally at the UAC headquarters. You pull out your service handgun, and enter the main gate suspecting the worst. Little do you know, but you are about to embark on a journey to the overseers world, the dawn of a new battle on another plane of existence. Hopefully, you have what it takes to clean out the alien world, and find the portal leading to the plane of hell itself; hopefully, you can find and destroy PERDITION’S GATE.

Levels
The map names were taken from the output of PG-PLOT.COM (executable file on the disc). The names mentioned on Tom Mustaine's website differ and when available are listed for reference in parentheses.

Earth

 * MAP01: UAC Main Lobby, Shipping and Receiving/Main Gate (UAC HQ)
 * MAP02: UAC Executive Areas, Interlock (UAC Complex B)
 * MAP03: UAC Executive Areas, Recreation Area/Yard (Recreational Yard)
 * MAP04: UAC Executive Areas, Storage Area (Storage Area)
 * MAP05: Executive Areas, Sub-Basement Entry (Sub-Basement)
 * MAP06: Sub-Basement, Waste Areas (Delta Area)
 * MAP07: UAC Nukage Areas, Nukage Monitor/Flow Control Facility (Toxin Refinery)
 * MAP08: UAC Nukage Areas, Waste Tunnels/Drainage Tunnels (Drainage Tunnels)
 * MAP09: UAC Experimentation Labs, Hangar/Storage Area (UAC Experimentation Center)
 * MAP10: UAC Experimentation Labs, High Security Area
 * MAP11: UAC Secret Teleporter Lab (Teleporter Labs)

World of the Ancients

 * MAP12: Entryway to the Worlds of the Ancients (Ancient Gate)
 * MAP13: Distant Worlds (Teleport Platform)
 * MAP14: Transfer Locking Area
 * MAP15: Teleporter Central (Teleporter Center)
 * MAP16: The Alien Shrine (Teleporter Power)
 * MAP17: Interdimensional Control (Teleporter Junction)
 * MAP18: The Throne of the Vile (Computer Center)
 * MAP19: Closer to Hell
 * MAP20: The Last Stand (Hell Gate)

Planet Hell

 * MAP21: Hell's Gate
 * MAP22: The Deepest Reaches
 * MAP23: Hell's Gymnasium
 * MAP24: The BloodStone Gardens of Hell
 * MAP25: Hell's Park
 * MAP26: The Blood Tunnels
 * MAP27: Hell's Masterpiece
 * MAP28: High-Tech Hades
 * MAP29: The Bomb Facility (Bomb Facility)
 * MAP30: The Escape (Escape!)

Secret Maps

 * MAP31: World of Wonders: The Planet of Living Rock
 * MAP32: World of Wonders: The Sea of Radioactive Waste