Squirt gun: a weapon which can be loaded with a potion (using up the potion), giving it ammo for 5-10 shots. When you fire it, a liquid projectile flies through the air, and causes potion effects (identical to those of throwing a whole potion) to whatever monster it hits.

It would be silly to define a separate liquid projectile object for each type of potion; probably the best implementation would be to have a single “splash of potion” object and use some field on the object, like corpsenm, to track what sort of potion it is.

Loading water into the squirt gun can be used to discipline pets.

Differentiate the neutral alignment by making it not really about killing. Instead, neutrals get rewarded for forcing monsters to back down, surrender, and get left alone peacefully. (Sapient monsters will beg or gesture for mercy when brought down to sufficiently low HP; non-sapient monsters will produce some other message). To keep loot fairly balanced, a monster that surrenders will drop its gear.

Extension of the feature in several variants where monster spawns are concentrated on the upstairs during the ascension run: occasionally, instead of spawning a monster, generate an organized group which is trying to get the Amulet, usually made up of sapient monsters (such as a group of soldiers, or a few priests of the same god, or some elves led by a couple elf-lords). Possibly, this only happens after you get back out of Gehennom and are again visible to the other gods.

Make monster summoning less common, but make group spawns more common. (Not necessarily meaning group spawns caused by monster summoning.) In particular, when a monster that is a lord or prince to its kind spawns, it should always spawn in some associated retinue along with it.

New Biologist role, which revolves around polymorphing monsters, brewing potions (probably non-alchemically), and possibly collecting samples from monsters.

Possibly, they start with a number of potions of booze, but are penalized for drinking booze; it’s intended to use for brewing with samples. They also possibly have a guidebook describing recipes (other roles can do this too, but lacking a guidebook they won’t be able to do it very well).

Starting equipment may contain:

• Alchemy smock
• Gloves, probably leather but maybe padded
• Goggles, a new eye-slot tool made of plastic that protects your eyes from splashes and spits just like the visored helmet
• Knife
• Walking shoes
• Wand of polymorph (questionable)
• Tripe and vegetables to tame monsters

One take on the quest: it sees you fighting the Black Mold (a mold that constantly multiplies itself and attacks with random elemental damage, including possibly disintegration, when touched). The quest artifact is the Elixir of Immortality, but this is not possessed by the nemesis; instead you have to brew it yourself using an ingredient found on the goal level and which will be destroyed by the Black Mold if you don’t get there first. The Elixir isn’t needed; the quest is counted complete if you destroy all the Black Mold.

They can get Expert in only a few skills, including knife.

They are penalized for “animal testing”, which is polymorphing or otherwise abusing living peaceful or tame monsters. Or possibly it’s okay as long as the subject isn’t killed. However, they are rewarded for other forms of experimentation.

A Yendorian Army monster will never hit another Yendorian Army monster with a ranged attack, to cut down on them killing each other, and also because they ought to have good enough skill and discipline to avoid friendly fire.

If you are mostly surrounded by puddings, they will merge together all at once and engulf you. This is a delayed instadeath in several distinct stages:

1. The puddings tower over you and merge together, preventing escape. You are engulfed, but you can still do things like attack or zap a wand of opening.
2. One or two turns later, your arms and legs are grabbed. You can no longer use most items but may still be able to cast spells and read scrolls.
3. The pudding spreads over the rest of your body. You can’t speak or do things that require speaking, though prayer is still possible.
4. The pudding is forced down your throat, dissolving you from the inside. This either kills you instantly or gives you a few more turns to live if you have magical breathing.

When a creature is completely surrounded by enemies that have hands, or is completely surrounded by enemies that have hands except for squares it can’t safely move to (like walls, or water that it would fall into), every attack made against that creature is an automatic critical hit. This is to make it more difficult to just wade through a sea of monsters while ignoring most of their hits, and incentivize having pets to surround an enemy with.

Possibly, do a lesser version of this (critical hits only some of the time) when a creature is almost but not completely surrounded. Though it should probably require a certain amount of adjacent enemies or something; two opponents facing off in a straight, empty passageway shouldn’t count as “almost completely surrounded” by the walls.

Several issues have been pointed out with this system if implemented naively: getting “surrounded” by two monsters in a corridor or being surrounded instantly with summon nasties or a cursed scroll of create monster could pretty much spell instant death. The original idea was that being surrounded basically amounts to being held down so that all hits have maximum accuracy.

Revamping melee weapons:

1. Slashing (swords, axes) and blunt weapons (maces, flails) deal about the same base damage.
2. Swords’ main advantage is that they have a high chance of inflicting bleeding. Blunt weapons have a very low bleed chance but armor reduces their damage a lot less.
3. Bleeding steadily decreases the HP of the bleeding creature. It’s debated whether this should remove a few HP per turn (which would require increasing the HP of everything by a factor of 10 or so) or whether there should be a random chance (around 10%) of losing 1 HP on a given turn. (Possibly an algorithm that makes a monster lose 1 HP on one turn in every 10 - but the exact turn of HP loss isn’t predictable. For instance, if hash(monster id + (turns / 10)) % 10 == turns % 10, lose HP due to bleeding on this turn.)
4. Certain monsters are immune to bleeding, notably undead, golems, elementals, and others that don’t have vitals of any sort. These tend to be better killed with blunt weapons.
5. Bleeding can be fixed (or at least stanched) with bandages. Cloth items can be torn up to make bandages.

Revamped combat system:

1. All melee attacks randomly select a specific area of the body to hit, as well as regular misses, all out of the same pool.
2. Higher skill biases the pool “inward” on the body - some of the miss percentage will turn into outer limb hit percentage, some of the inner limb hit percentage will turn into a body hit percentage, etc. Head strikes are rare, but can inflict stunning as well as damage, although helms mitigate this somewhat.
3. Armor protects the area it covers, but its material or AC is a big factor in damage reduction: weak cloth armor takes full damage just like no armor, plate armor generally reduces damage completely except for rare armor-chink hits, etc.
4. Armor is strictly organized into four tiers of cloth, leather, mail and plate.
5. Positive weapon enchantment lowers the armor’s effective tier. Positive armor enchantment raises its effective tier. High armor enchantments are made substantially harder to come by.
6. Thrown daggers and knives are effectively useless against mail and plate armor, except for rare chink hits. Bow and arrow is useless against plate armor unless enchanted. Crossbow, however, is still useful against it. However, a successful shot deals a lot of damage.
7. On the monster side, many monsters (e.g. dragons) have effective full-body enchanted plate. Some monsters such as giants may also have powerful attacks that bypass armor.
8. Along with the limb-targeting system, it is also possible to break limbs. Broken limbs can be cured with prayer or most types of healing.

Low-level sapient creatures avoid you and will not attack if you are visibly equipped with top-tier gear such as dragon scale mail or artifact weapons, unless they decide they have some advantage with which to beat you.

A much more fleshed out interaction system for sapient monsters. It is initiated by chatting, which opens up a menu offering four key verbs: Ask, Tell, Show, and Give.

Ask is used to gain information from a monster; this could be a whole bunch of things, from rumors to identification to information about the dungeon. Each type of monster you can ask things of has a limited knowledge base, and this knowledge base may contain some inaccurate information. Especially interesting is the possibility that you can ask someone for identification, and they tell you what they think it is - which could be right or wrong, but a good clue either way. You can also ask someone to join you, and pay them some gold to tame them for a certain amount of time.

Tell is currently a less developed part of this idea; the only thing suggested so far is that you can tell a creature about traps you’ve discovered, which will make those traps known to the creature. You can also use “tell calm” on your pets to make them refrain from attacking peacefuls.

Show lets you select any item from your inventory to show to the monster. This can be used for intimidation (e.g. showing a stack of iron skull caps to a goblin).

Give lets you give items to a monster, which in some cases, depending on the AI, lets you test the effects of items.

Note that a potential pitfall of such a system is that if it’s complex enough to do interesting things with, it is probably going to be hard to use without spoilers. And if it’s uncomplex enough, it runs the risk of most possible responses being “I don’t know/care about that”, which also makes it hard to use without spoilers. A middle ground between these is likely to require an enormous amount of work.