I got to play d20 "A Game of Thrones" this weekend.

[Enforcer]

What about magic? I've heard it's feat-based.

It is. And it's meant to be part of the story--no *Zap!* and you're healed, but actual rituals are involved.

Does armor give DR or is it just an AC modifier?

DR. But shields give either a Defense roll modifer or DR, depending on whether the attacker chooses to try to bypass the shield or attack through it.

Is there a noble core class?

Yes.

What about critical hits with major effects, like in the Black Company Campaign Setting or Swashbuckling Adventures etc.?

Crits work pretty much as normal as far as when you get one and how much damage is done. Each character also has a Shock value (Con based) and when a character gets hit for more damage than their Shock (after DR is applied) they have to make a check or be stunned. Most crits are gonna require a Shock check. And, whenever you have to make a Shock check from an attack that breaks the skin, you take a Serious Injury that bleeds for 1hp per round until you get First Aid--even if you make your Shock check. And every character has far fewer hp than in D&D, making such an injury pretty serious even for the warrior-types.

 

[Maester Luwin]

Hey everyone! Also remeber under this system any damage taken is going to hurt. There are no healing spells or potions. Rest under the care of a Maester (& the use of heal skill/ Leechcraft feat) is the best this world offers (again staying true to the books). Armor acts as DR but remember that all classes will have fewer HP's as well. As Doug has said there are a lot of combat options but be wary... Thanks Maester Luwin

 

[Maester Luwin]

Hey everyone! One thing in this system which really makes sense is that every character has a fatigue threshold (this is optional). This is the number of rounds that a character can fight before becoming fatigued. Now armor acts as DR in this system but it also reduces your Fatigue Threshold. Once a character reaches his threshold, the character takes a -1 to hit/ defense rolls (which is cumulative ) each round. So cons are important not just for HP but also for how long one can fight. Also feats like endurance become important in this system. With these mechanics one can recreate a fight scene like the one between Ser Vardis & Bronn! Maester Luwin

 

[Enforcer]

Also, the fatigue threshold makes Endurance worthwhile. And, it should be noted that the fatigue threshold is an optional variant of the optional fatigue rules (where you roll each round to see if you're fatigued, and could be fatigued on round 1).