Should you have any questions, shoot
I'll try to cover the combat system briefly for you :
Melee is like in any other game. Except Backstabs deal up to 5 times more damage, and Helmets protect from critical hits.
Attack speed, accuracy and damage are increased with character levels, as well as Weapon Proficiency points and some items and spells.
It's a attack vs Armor roll every time. There are 4 types of physical damage. Slashing, piercing, crushing and missile. Some items give partial resistance to one or more types of damage. Some give increased Armor Class.
Some targets are immune to a type of damage, some are immune to non-magical weapons, some can be affected only by really powerful ones (example : Demi-Liches can only be hit by +5 weapons!)
There are spells that grant magical weapon protection for 4 rounds (24 seconds)
There are spells that grant protection from non-magical ones.
Now, magic system is why i love Baldur's Gate. It's a rock - paper - scissors one.
A chain example :
A mage can protect himself with Stoneskin. It stops up to 10 physical attacks (not elemental nor magical)
It can be dispelled with Dispel Magic, Remove magic, Breach or hitting the mage 10 times.
Dispel and Remove magic can be stopped with Spell Immunity : Abjuration
Breach can be stopped with Spell Defense, Spell Trap, Spell turning and more.
Spell Turning is dispellable with Spell Thrust, Secret word and more.
Spell Thrust cannot be cast on an invisible target
Spell Thrust is also too weak to affect a target protected with Spell Trap
True sight, Purge Invisibility, Oracle and more reveal invisible targets.
Non-decection stops the above spells, with the exception of True Sight.
True sight can be stopped with Spell Immunity : Divination
But Oracle ignores Spell Immunity Divination..
Et cetera, Et cetera, Et cetera
Basically the more complex your defense chain is to dispel, the more time the enemy needs to make you vulnerable.
If mage level is high enough, there is always a way to work on enemy protections.
There are 7 types of magical damage. Magic, Fire, Magic Fire, Cold, Magic Cold, Acid, Electricity.
There are spells, scrolls and potions that partially protect from some (In Kuroisan fight we were all protected from Acid at 70% or more)
There are spells, scrolls and potions that FULLY protect from some
There is also the last resistance : Magic (not to confuse with magic damage)
It's a chance of ignoring a hostile spell altogether.
However there are a few spells that ignore magic resistance.
Which also can be increased by other spells, scrolls or potions.
There are 9 spell levels for Arcane spellcasters (Sorc, Mage) and 7 levels for Divine (Priest, Druid)
Mage can cast only one spell per round (6s) with the exception of very powerful end game mage using a very powerful, end game ability that removes the cooldown.
Spellcasting can be interrupted by damage, Crowd Control or effects such as Silence and Miscast Magic.
Mage spellbook is limited.
Insanity makes enemies deal double damage, and the mods i'm using upgrade them both AI wise, and attributes/ resistances / gear wise.
I hope it helps!