Special level

A special level has some unusual features that differ from the normal dungeon-, mine-, or maze-style levels. Usually some parts of these levels are not randomly generated. The special levels are made with a special programming language, which is then compiled into a .des -file by lev_comp. NetHack loads the .des-file when needed and creates the special level based on the instructions in it.

This list might not be complete.

• Minetown
• Mine's End
• Oracle
• Sokoban
• Sokoban top level
• Bigroom
• Fort Ludios
• Rogue Level
• Quest portal level
• Quest top level
• Quest bottom level
• Medusa's Island
• Castle
• Valley of the Dead
• Fake Wizard's Tower
• Wizard's Tower
• Vlad's Tower
• Asmodeus' Lair
• Baalzebub's Lair
• Juiblex' Swamp
• Orcus' Town
• Bottom Level of Gehennom aka Vibrating Square
• Moloch's Sanctum
• Elemental Plane of Air
• Elemental Plane of Earth
• Elemental Plane of Fire
• Elemental Plane of Water
• Astral Plane

This list is better organized and more complete, as well as filled with information, at [1]