im hoping nothing has changed too much since ed 2
You are already familiar with it, you just don't know it. NWN2 operates under 3.5e rules. So proficiencies are gone and thief skills are gone and replaced by feats and general skill banks. There are class skills which you can invest points fully into and all others are cross class that you can only bring up by half. feats are special features you can add to your character that are unique abilities like martial weapon proficiency and cleave. They changed ac and threw out THAC0. Now the ac number represents the minimum sum you have to roll with a d20 to make a hit. But pretty much all the rolls use a d20 for calculation of passing or failing. All skill performances require a skill check, except in non competitive situations where the dm allows you to take twenty or ten. Think jumping over a small chasm with no pressure of being chased or other extenuating circumstance. Otherwise its the same game. Another change is that everyone uses the same experience table, and xp from monsters is tailored to the strength of the party relative to the threat/difficulty of the monster.