When the player is on a water space, track whether they are submerged or swimming on top of the water. By default, entering water without the risk of drowning still puts you at the bottom, but you can use < to ascend to the top.

A primary effect of this is to establish consistency with what you can and can’t interact with while in water - it doesn’t make much sense that monsters standing on an adjacent land square, or monsters flying on an adjacent water square, can hit you in melee when you’re underwater, nor the other way around. If being on top or bottom of the water is tracked, these cases can be prevented, but care would have to be taken so that the hero can’t dive underwater and be completely safe and able to recover with impunity.

One possible mitigation (in addition to blocking an underwater hero from using melee attacks on adjacent monsters that aren’t in the water themselves) would be to make monsters that can’t currently attack the swimming hero avoid getting into melee range. Though this still wouldn’t deal with zapping them with spells from a safe distance.

Boots of fleeing: they give bonus movement points based on how many turns ago your last offensive action was (offensive actions are things that would fade an Elbereth underneath you). For the first several turns after combat they grant no speed bonus, then gradually scale up to full speed. This means that remaining in combat grants you no speed advantage but lets you travel very fast if you avoid it.

In order to penalize situations where the hero is partly or mostly surrounded without implemeting a complex flanking system: Every monster attack that incurs damage reduction due to subzero AC makes your effective AC worse by the amount of reduced damage for the duration of that turn. This means that a crowd of monsters hitting you all at once will whittle down your defense and do some damage rather than damage reduction being in full force for each individual attack.

Some monsters, when dealing what otherwise would have been a killing blow, instead leave you at 1 HP, strip you of some or all of your possessions, and possibly vanish/teleport. Shopkeepers in particular may decide to do this (but some may still decide to kill you).

Sometimes, when fighting, a monster not directly adjacent to you that wants to attack you but can’t because there is a monster directly adjacent to you can move through the combat and end up on your opposite side, as a way to make chokepointing less of a dominant tactic.

Wearing kicking boots automatically adds a kick to melee attacks you make.

A monster in the n or perhaps W classes whose main gimmick is that they will dodge or short-range teleport out of the way whenever they see an attack coming. In order to fight them effectively, you can’t be straightforward in attacking. You can use displacement, ray-bouncing, or invisibility (but they’ll recognize you’re using that pretty fast and adjust tactics accordingly).

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.

Monks who have passed through all the “Student of X” titles may go back and speak to the Grand Master to choose an elemental specialization and receive a power related to it. Stone gives a physical damage reduction; Air gives a random extra movement point here and there and a rare chance of dodging an attack. Water automatically counterattacks melee attacks. Fire boosts attacking power or gives extra attacks.

Extend Cleaver’s wide-arc hitting behavior to all battle-axes.

Paralysis only freezes you in place on a square; it doesn’t prevent you from attacking and taking other non-movement actions.

Being attacked while asleep doesn’t have a random chance of awakening you, but instead it reduces your remaining sleep time by some amount.

If you aren’t wearing armor or a shield and have high martial arts/bare hands skill, you get an AC bonus (probably a higher one for martial arts). The bonus should probably scale up with higher skill, and should be generally higher for martial arts users than bare hands users.

If a monster has horns, AT_BUTT attacks deal extra damage.

Damage reduction from AC happens before half physical damage instead of afterward.

Refactor to-hit mechanics into a simple 1d(attacker’s bonuses) versus 1d(defender’s bonuses) computation, where the attacker hits if their roll is higher.

Weapon differentiation - possibly a replacement of the old D&D “damage vs. small / damage vs. large” system currently in use. Weapons would do the same damage regardless of what size the target is, but might get a damage bonus or penalty based on if the target is vulnerable or resistant to piercing, slashing, or whacking/blunt weapons. Being resistant to this weapon type means that the damage is halved; being vulnerable to it means that the damage is multiplied by 1.5. Some obvious examples:

• Most undead are resistant to piercing damage. Skeletons are additionally vulnerable to blunt damage.
• Thick-hided animals are resistant to slashing damage.
• “Blunt is best against hard things, slashing is best against soft things, piercing is best against fleshy things”

Hitting monsters with a passive shock attack doesn’t hurt you if you’re hitting with a non-metallic weapon or your hands with non-metallic gloves on.

The higher your skill is with your wielded weapon, the lower the chance is that an enemy will yank it out of your hand with a bullwhip.

Attacking in melee with an unsuitable weapon like a launcher should negate the player’s Str bonus or monster’s weapon attack bonus.

A #stomp command that lets you stomp on a grounded creature that is a certain number of monster size levels smaller than you. A hit will instakill it.

Add a defence/evasion skill, which is trained by having monsters miss the player (while not wearing torso armor?) and grants an AC bonus when enhanced.

Merge the damage versus small and damage versus large stats of weapons, since they don’t really matter that much and add mostly pointless complexity. Damage should be more dependent on skill than on the size of the target monster. The only problem is how to stop the highest-damage weapons from becoming used by everyone because they’re so optimal; perhaps skill should do something drastic like add an extra die with every skill level, allowing you to have weapons that are decent at low skill (by having multiple small base dice) but poorer at high skill (because adding more small dice doesn’t work as well).

Have the tab key be a shortcut for auto-attacking monsters (at range or at polearm range).

Bull rush command that lets a player shove a target monster back one or more squares. The relative size of the monster and player and the strength of the player are important factors. The character might move into the space of the displaced target.