The Soul Forge: a single-level branch off Gehennom that contains a smith. The smith will take two items of the same type and forge them together into one; in technical terms this destroys one of them and imbues the other with whatever object properties the destroyed one had. They cannot both be artifacts, and if one is an artifact, it will not be the one destroyed, so the properties from the other one will be transferred to the artifact.

The smith’s price is based on how many object properties the resulting item will have, increased if it will be an artifact. In dNetHack, the smith would require payment in soul coins, but in variants without those, they may just ask for gold or some other valuable. If paid in soul coins, the requested type of coin would be random but deterministic based on the object IDs of the two items.

Add two new elemental planes, those of Positive Energy and Negative Energy.

The Plane of Positive Energy:

• The full level is lit.
• Has lots of yellow lights, trees, and whatever plant-based monsters exist in the game.
• Everything is treated as if it has regeneration. The player can regenerate current HP past its maximum, but if this gets too far past the maximum, they instantly die from being unable to contain the energy (there are warning messages to this effect as you approach this point).
• Items in the player’s and monsters’ inventories can randomly get blessed, enchanted, or charged - even if this runs the risk of overenchanting and destroying them.
• Eating any food restores HP as well as nutrition.
• All exercisable attributes are exercised at regular intervals.
• All sleep effects are negated.

The Plane of Negative Energy:

• The full level is dark.
• Contains lots of undead.
• Everything constantly loses hit points. If you have regeneration, it either nullifies or only partly nullifies this effect.
• Items in the player’s and monsters’ inventories can randomly get cursed or lose enchantment or charges (going negative on things which are capable of being negative).
• You lose several times as much nutrition per turn as normal.
• All abusable attributes are abused at regular intervals.

Add a minetown variant called “Wine Town”. It would largely follow the regular Minetown precedents of having the Watch, a temple, a (high probability of a) general store, but would also have at least 2 potion stores, a couple random potions of booze lying around, and a large “drinking hall” room.

Add a Craftsmen’s Guild to the game, as a method of advanced crafting (unlike the player’s simplified crafting such as alchemy crafting potions into other potions, or combining a blank scroll with a magic marker to make magic scrolls). The guild either has its own dedicated special level, or occupies part of a preexisting special level.

• The guild is populated with master craftsmen who work on the principle of “valuable junk items + very large sums of gold = desirable items”. They can also do some things available to the player, like increasing weapon enchantment, without needing the specific consumables needed for the player to do it.
• Would serve as a replacement or stand-in for the black market. Resolves some of the problems with balancing black market shopkeepers: if you kill the black market staff, you can have every item in the market, so black market staff must be insanely powerful. If you kill a master craftsman, however, you don’t get anything of value. Therefore, master craftsmen don’t have to be insanely powerful, or even good fighters.
• Not as good as wishes; there are some things they cannot make for you, like magic lamps, and many magical tools. You cannot specify enchantment or blessing either. For items for which enchantment doesn’t matter, the material cost will be higher.
• The interface works by #chatting to them. They will ask you what you want to create, and you enter it (using the wish parser logic to extract the proper object class), and then they will tell you the items and gold they will need for it. These could either be randomized or use certain fixed ingredients with some randomization or use completely fixed recipes; if randomized it will be deterministic for that item for that craftsman in that game. You are then prompted to select the items from your inventory.
• For gold and other balance reasons, this would probably work better the farther it is into the game; maybe it could even be found deep into Gehennom. Maybe you even have to liberate it from a demon lord.
• Craftsmen might include:
  • Metalworkers (see below)
  • Wandmakers (produce wands)
  • Scribes (produce scrolls and spellbooks)
  • Alchemists (produce potions)
  • Toolsmiths (produce mundane and some magical tools)
  • Jewelers (produce rings and amulets)
  • Sculptor (produce statues and figurines)
  • Leatherworkers (produce leather items and saddles)
  • Chefs (produce food)
  • Arcanologists (transfer charges/enchantments from one item into another, consumes only gold and not items)

Metalworker notes

Metalworkers are probably the most important sort of craftsman for many characters. There could be multiple types, each specializing in one type of metal, or just one type that does everything.

• Silvering items (or gilding, or copper-coating) should require you to use up junk silver items equal to some amount of weight proportional to the weight of the new item. The zorkmid cost of silvering should be very high.
• A forge room type (probably containing lava and maybe some junk items like iron chains) could be added which has one or more smiths in it (silversmiths, goldsmiths, blacksmiths).
  • Goldsmiths seem rather pointless right now, since there is only one gold item (the ring). They would be more useful if gold equipment existed and conferred some benefit.
  • Blacksmiths don’t have much to do as far as turning items into iron goes, but they could produce iron weapons of a type the player wants, or repair and improve iron weapons and armor (increasing its enchantment).

Assuming an implementation containing multiple puzzle branches (to offer players an alternative to Sokoban), have all the branches start from an “antechamber” level off the main dungeon. This is a small unpopulated level, and contains terrain clues around each puzzle branch staircase in it, such as boulders and strangely shaped walls for Sokoban, ice if there is an ice sliding puzzle, etc.

A new Mines’ End variant that contains a guaranteed scroll of earth, gold golems, and an earth elemental as a reference to some Swiss folklore involving gnomes. Possibly also add a healer statue named Paracelsus, who was one of the first to name gnomes as such.

Create six new semi-elemental planes that each corresponds to a pair of Elemental Planes. These don’t have to behave exactly like the combination of the two elements (e.g. the Plane of Water and Plane of Earth intersection doesn’t have to be a Plane of Mud); the inspiration for them is levels like SpliceHack’s additional semi-elemental planes.

Randomize the order of the elemental planes, and insert the appropriate three semi-elemental planes between each pair of elemental planes. This leads to an End Game that is highly different from game to game, but has continuous transitions at the same time.

Revamp Gehennom by making its main branch substantially shorter, a “hub” branch containing stairs or portals to a bunch of sub-branches containing demon lords’ lairs. Most of the lairs are optional, but at least some of them are required in order to enter the Sanctum. Each demon lord that you don’t kill, however, incurs a unique, harsh effect or debuff on you once you have the Amulet. Suggested ones include:

• The mysterious force, as it exists in vanilla.
• When you try to ascend the stairs, they vanish and several illusory copies of stairs appear across the level, along with one real one which you have to find.
• Walls extrude from existing walls around the hero in random directions, never entirely closing off, via a cellular automaton that looks for walls with a 3x2 area of walkable spaces in front of them, with the space directly in front a regular floor space - the effect of this given enough iterations turns the terrain around you into a maze.
• Generic damage over time, not severe but enough to provide a headwind. Or partial or total disabling of natural regeneration.
• Asmodeus: Some damaging cold effect that happens periodically, or your cold resistance is nullified and replaced with a vulnerability to cold effects.
• Baalzebub: Something to do with insects, either periodic summon insects from nowhere or stronger/more frequent insects
• Juiblex: You may randomly become ill, or have your regeneration dampened or something
• Geryon: Hordes of buffed q generate and rampage periodically.

Sometimes Medusa’s Island is replaced by a new level Circe’s Island. Circe has a nasty polymorph touch attack (or perhaps can even cast it as a spell, at range), and may be accompanied by sea monsters Scylla and Charybdis.

Add paraelemental planes to the ascension run, placed before or after their corresponding elemental plane:

• the Plane of Ice corresponding to Air or Water,
• the Plane of Ooze/Mud corresponding to Water or Earth,
• the Plane of Smoke corresponding to Air or Fire,
• the Plane of Magma corresponding to Fire or Earth

Either a random one of these planes would be inserted along with the four regular planes, or they would all be inserted but there would be mini-quests or objectives in the Mazes of Menace that when completed would prevent those planes from generating or skip over them.

Make the start of the dungeon (level 0) a Minetown-like affair with peaceful shops. (Very possibly you can’t reenter this level once descending into the Dungeon, unless you have the Amulet.) When you reenter it on the ascension run, it is in ruins, with a portal to the Planes newly created there.

If a special level fails to load, its fallback is not to make a maze - instead, it creates a simple large rectangular open area stocked with some random monsters and objects (and stairs, if relevant). It is named the “Bug Room”.

Level that contains a structure with a lot of gargoyle statues. Some of the statues are statue traps.

A special level where the area you can levelport into does not contain any stairs.

A level or branch that forces permanent hallucination while you’re in it. Hallucination blocking from Grayswandir may or may not function.

New Medusa-alternative level (like the Grue and Echo levels in dNetHack): Chrysaor’s Palace, containing a fair amount of water, soldiers, and Chrysaor, who wields a +10 gold broadsword and a gold shield of reflection, and whose attacks and resistances are on par with Croesus or even better.

After the Valley, have a guaranteed special level “The Gates of Hell”. This level design is very clear: “This is hell. These are the gates, and they are closed. You are not wanted here. Go away or perish.” The level is a large cavern, with a massive arc-like fortification across either the left or right side. The gates are implemented with both iron doors and a drawbridge across lava. There is quite a lot of lava, and a lot of demons inside and outside the fortification.

A special level (possibly in a quest, Rogue-locate is a good candidate) level that contains a pond outside some building or city wall, with one iron bars square on the other side of the wall, inaccessible except by going over the water. Behind it is a (maybe randomly generated?) network of corridors inside solid rock representing a sewer. Either there’s something in here required to complete the level, or there’s an alternate path to complete the level, or there’s some treasure.

Gehennom level that is cavernous but with 1-3 defensive fortifications consisting of a slightly twisty undiggable wall with turrets or guardhouses staffed with demons, and lava moats with drawbridges. Stairs on opposite sides of the fortifications.

Mines’ End variant that is an actual mine, with many twisty corridors dug out of the rock, and many unmined gems in the rock. The luckstone is unmined, in one of several possible spaces, not adjacent to any corridors but not too far away from them, and certainly not as far away as in the Wine Cellar. A pickaxe will be guaranteed somewhere on this level.

A Mines’ End that has a water theme, though not necessarily as extreme as the Gnomish Sewer.

A Big Room variant that is an idyllic scene with a nice river cutting through it with some scattered trees and maybe a couple fountains and a lake. Idyllic except for the usual bunch of monsters, of course.

When you get arrested by the Watch or a guard, you are teleported to a prison level, from which you must escape.

Demigod level containing a boss which is generated from a real player who recently ascended.

Dungeon branch or level filled with toxic contact gas (breathless doesn’t help, or only helps a little) so that you constantly take damage and must bring a lot of healing with you. The deeper you go, the worse the gas becomes, but the loot gets better.

A Gehennom Gnome Fortress, like a demon lair except with gnomes. The gnomes are physically weak but have strong crossbow attacks (and clockwork minions).

Convert some of the Gehennom filler levels into ADOM-like greater vaults that contain many challenging monsters and an artifact.

Single-level branches whose portals, found in vaults, disappear after one use; they are subdivisions of the Magic Memory Vault, and modeled after ADOM “vaults”. These are basically challenge levels, smaller and less rewarding than Fort Ludios (the master branch), that contain some nice loot and harder-than-usual monsters. Portals to them can also be found in vaults in Gehennom.

If Orcish Town is generated, guarantee a “peaceful” Mines’ End where all the inhabitants, surviving shopkeepers, watchmen and the priest have fled. Chatting to the priest will make him ask you to clear the orcs out of Orcish Town, upon which chatting to him again will make him grant you a protection boon and give you a luckstone.

• Internally, this can be done by setting a global flag if and only if Orcish Town generates, and only load the peaceful Mines’ End if that flag has been set. If you manage to get to the bottom of the Mines without yet generating Minetown, you are guaranteed not to generate the peaceful Mines’ End, and Orcish Town will not generate either.

Gehennom should be half as long, 10-12 levels, and should be mostly or all unique levels that are randomly chosen from a larger set.