While many a system (or supplement) has had claims made in earnest that it is hardcore "sword & sorcery", or whatever, Conan OGL
actually is. Well, maybe not
hardcore, but yeah, it's S&S alright. Captures the Conan feel quite well, I think.
If you prefer full colour, get the Atlantean Edition. If, on the oither hand, you are after a bit of extra rules content, get the 2nd Edition.
One of the most notable aspects is the magic system. This is not your D&D-style magic, by any means. Sorcery can benefit from a few things, such as sacrifices. It also, however, can lead the practitioner directly into the depths of madness, and other side-effects of Corruption. Runaway Magic can be fun, too.
"Races": All just humans from different areas, different cultures. Some small mechanical variation, at times reaching the D&D races level of such.
Classes: Barbarian, Borderer, Noble, Nomad, Pirate, Scholar, Soldier, Thief. I believe the 2nd edition book also has the Temptress, which was originally found in a 1st edition supp. Multiclassing is "free", and favoured classes (from "races") - rather than penalising deviation, as per 3e - reward sticking to the standard archetype(s), by granting bonus feats, at 1st, 5th and 10th level, assuming a favoured class has been adhered to for that time.
You still have skills and feats. Some feats are quite neat, with good combat (or other) flavour. Abilities not only get individual inceases at every fourth level, but an increase to all of them at once, every sixth level too.
Fate Points are very cool - they offer
Left for Dead,
Mighty Blow,
Repentance or
Destiny, as the player wishes. You start with three FP, and once used, they are gone forever - more can only be gained by accomplishing major goals; that kind of thing.
Weapons do more damage. Armour provides DR, not AC. You have Dodge and Parry scores, which increase according to class(es) and level. Mostly, you'll be wanting to pummel your way through said DR, but those treading the Finesse path can instead try and exploit chinks in the armour, thus bypassing it altogether. Another twist is that some weapons have an AP (armour piercing) rating, to help somewhat with, that's right, piercing armour. Armour can also be reduced in effectiveness, if it takes a large amount of damage in one go.
High Living has to be my favourite rule in the Conan RPG. Basically, PCs must spend a considerable portion of their ill-gotten gold on. . . well, ale and whores. More or less.
Hopefully, that is enough to give you an idea.
edit --- Oh, and if you want a gazetteer of "the lands of Conan", get the Road of Kings supplement, or Return to the Road of Kings (2nd ed. expanded version). Either one is by far good enough to use with whatever system you favour, should you find that world at all compelling.