Combat

True Berserker Bonus

Monks don't get a True Berserker bonus. 

Can't get a True Berserker bonus unless you are wielding a weapon (Beastfighters don't seem to be an exception.)

Shields, Necklaces, Rings, Bracers, Tools, and Missile weapons can be worn and you're still a True Berserker.

Melee ToHit

Base value bonuses:

Dwarven Shield & Dwarven Rune Axe paired give a bonus of 10 ---- If Shield is in the right hand and Axe in the left. Needle and Sting's bonus is 50. Stunned gives -4, Blind -4, Drunk -1, Invisible +4, Blessed +2, Meelee Weapon Master is 3, Basher Powerful Strike & Mighty Strike give 1, 2, 3 if weapon is >=100stones; Brawler gives 2 if barehanded, Bonus of Strength - 12 / 2 (if positive, no decrease if negative) Strength - 9 / 2 (only if negative, no increase) All ToHit effects from equipment. Monks get +PCLevel ToHit if Unarmed and Unburdened. Beastfighters get +PCLevel ToHit if Unarmed. If weilding a spear (or spears?) alone (without a shield) then +2 -1 if Satiated, -2 if Bloated.

From Base: Regular Torch 1d4 Thorns 3d3 Assassin or Thief Level 12+ Backstab = Double damage OfTheSun *2 vs Undead Ashen =0 vs Undead Mighty Blow =*2 or Tremendous Blow =*3 Add Monster PV if Phase Dagger Silent Room =*10 Life Room =/10 Blessed =*1.5 vs Undead/Demon Cursed =/2 vs Undead/Demon If Meleeing with a Missile weapon, /2 If using Holy Avenger and Paladin, *2 If using Holy Avenger and not Paladin, /2 If Torch, +2d4 damage vs FireVulnerable If Lawful Weapon, +1d8 vs Chaotics If Lawful Weapon, +1d8 vs Chaotics If Hateful weapon & Beserk, +2d6

• 1d4+1 if Crit, or *1d4+2 if Slaying

If Level 50 Assassin, If Mob Total Level < 50, If not Unique: (50-MobLevel)*2 / 1000 for insta-kill If Level 32+ Monk, If not unique, If Humanoid and not Undead/Construct, and size <= 2 OR Level >= 40: (50-MobLevel)*2 / 1000 for insta-kill If some weird variable set (Maybe related to two-weapon combat?), /5 If mild weapon, /5 If penetration, Add monster PV

Two-weapon Combat

Take your Two-weapon Combat skill value, and multiply by 0.05. from that, subtract: ((RightWeaponWeight + LeftWeaponWeight) / 10 [20 if Ranger Level32+, 40 if Ranger Level50]) - 6; if this results in a negative number it's changed to 0. Then there's a mysterious benefit for all rangers. Add ambidextrous talent if you have it (+2).

more to come...

Missile ToHit

Archers get +1 ToHit per level of experience. 

Assassin, Bard, and Ranger get a level / 3 bonus ToHit. Paladins, Thieves, and Barbarians get a level / 2 bonus ToHit (Possibly also Fighter).

Other classes get a level / 4 bonus ToHit. 

Archery Skill / ? = ToHit bonus, appears to be different for Archers.

Concentration / 50 ToHit bonus for all?

(Dex - 12) / 2 = +ToHit (Min 0)

(Dex - 9) / 2 = +ToHit (Min 0) (**This is probably actually a minus if less than 9, I should double check.)

Eagle Eye +3

Keen Shot +2
Good Shot +1
(That is to say, the game manual is correct.) 

Blessed +2

Burdened level affects it in some fashion...

Invisible +2

Drunk -3

Archers +6

Blind -4

Stunned OR Confused -4

Satiated or Bloated -1?

Add in some other factor depending on level and class...

Merchants throwing gold get a bonus of their level -1.

Add in appropriate affinity bonuses.

If room has 'shifting breeze', /3.

If stuck in webs, /2.

Add Tactics bonuses.

Something else might change after this for Paladins, Rangers, Monks, Barbarians, and Beastfighters (Fighters too?)...

Critical Hit Chances

If slaying, Counts as crit and skip crit section. 

Base chance of 1/20 (Luck Modifiers alter this depending on good/bad luck, Murderous weapons double your odds)

OR FindWeakness/500 (FindWeakness/1000 for Missile attacks) 

OR If Backstabbed, 1/4 OR If +Crit Weapon, CritValue/100 (This is a semi-hidden number that is likely different for each weapon. I actually do NOT see a bonus from other +Crit equipment being added in; this should be tested.)

OR If Lvl 25+ Fighter, 1/10 

OR If Lvl 25+ Assassin, 1/5 OR If Beastfighter vs Animal, CharLevel+10/120

(There may be other tweaks for Missile attacks versus Melee as well beyond just Find Weakness.)

Critical Hit chances of +Crit weapons vary from weapon to weapon: Bloody Dagger: 50% Whip of slaughtering: 50% Axe of the Minotaur Emperor: 40% Serpent's Bite: 30% Mighty Morning Star Grod: 0%

Critical hit boosts are only applied from weapons, so the following will NOT improve your crit rate when equipped normally (but should if you use them as weapons):

Bracers of War: 8% 

Ring of the Master Cat: 16%

Rust Monsters

Select a slot at random. If a ring slot is chosen and you are wearing gloves, select the gloves instead. No effect (or message) if the slot is empty or holds a non-metal item, or if the slot is armor and you are in the middle of donning or doffing some. Otherwise, the item is touched, and will be rusted if not rustproof; rusting rusty stuff destroys it.

Misc.

Rusty weapons do half their normal damage. 

Being a natural enemy of the undead is like always having a 'Slay Undead' power.

Thin Dagger "Cat's Claw" slays rats. 

Rabbit Knife slays battle Bunnies and Mutated battle Bunnies. Of the Sun deals double damage to Undead; Ashen does 0 damage to Undead. Holy Avenger not being used by a Paladin deals half damage??? Torches burn fire-vulnerable mobs for +2d4 damage (This is added after crits and other bonuses).

Emerald Dagger poisons more effectively than Poisonous weapons (1d6 duration instead of 1d2?)
Of Vampirism steals 1d8hp, gives -1Alignment, doesn't work on Undead/Constructs.
Necromancer level 25 ability gives damage dealt / 3 hp? Or if at max HP, gives some amount of PP. In addition, a Damage? / 10000 chance to get +1 Mana.
Throwing Shields should train Shield skill, needs testing. 

Cannot Backstab undead. Thorny Hands also add bleeding? Can't raise Weapon Skills if Very Defensive or Cowardly? Can't raise shield skills while Beserk?

An enraged monster has twice as many attacks as it normally would, and has 3 less DV. (They can become enraged by eating a comrade's corpse, among other things.)