Heck² patch

The Heck² patch provides a collection of special levels to replace some of the maze levels in Gehennom. The new levels consist of fixed designs amid random mazes; the placement of levels into the dungeon is random. The patch is against NetHack 3.4.2 but also works with 3.4.3. The patch has a home page.

The patch makes extensive use of the des-file format, often ordering multiple MAP and MAZEWALK commands to produce the new levels.

There are five groups of Heck² levels: heck-a, heck-b, heck-c, heck-d, heck-e. Each game has a 25% chance of a heck-a level, a 50% chance of a heck-b level, a 75% chance of a heck-c level, a 100% chance of a single heck-d level, and four of the heck-e levels.

The heck-a levels include:
 * 1) Demogorgon escorted by two shriekers
 * 2) Dispater escorted by green slimes and disenchanters
 * 3) mind flayers and master mind flayers
 * 4) Geryon escorted by doppelgangers and werewolves
 * 5) iron bars and iron golems
 * 6) liches
 * 7) Yeenoghu escorted by minotaurs

The heck-b levels include:
 * 1) a cross-shaped level
 * 2) a room with many trolls
 * 3) a stream of lava with red dragons
 * 4) a maze of lava
 * 5) a dark, open region
 * 6) a small pool with kraken
 * 7) parallel, vertical corridors
 * 8) hidden closets

The heck-c, heck-d, and heck-e levels are less exceptional, but they insert open areas into the maze and sometimes unusual features like pillars or rounded rooms; they also insert solid wall, sometimes reshaping a level like 'm' or 'w'.

The biodiversity patch incorporates the Heck² patch.