Before mentioning the core mechanics, I'd like to first say that if you're an old-school "GM is God" or "Benevolent Dictator" GM, then you'll want to know that the Mophidius 2d20 RPG system uses a currency mechanic of Momentum and Fortune for players and Doom for the GM to add cinematic effects to the game. This currency mechanic can be house-ruled away from the core "roll dice to make a skill check" mechanics. Myself, I'm fine with it, since I prefer to throw challenges at the players, and let the system worry about game balance.
Skill Checks: Otherwise, Conan uses the commonly seen skill check of making a die roll versus a target number. Characters have Attributes, Skill Expertise, and Skill Focus. Attributes are inherent abilities, and are Agility, Awareness, Brawn (Strength), Coordination, Intelligence, Personality (Charisma), and Willpower. Skills represent specialized training, and each skill is tied to a particular Attribute. When a character makes a skill test, they roll 2d20. Each result equal to or below the character's Attribute plus Skill Expertise is a success. However, if they also roll equal to or less than their Skill Focus, they receive two successes instead. Before making a roll, the game master assigns a difficulty level, typically D1, to determine how many successes needed. If two characters are in opposition to each other, they are considered to be in a Struggle. Both make a skill check against a Difficulty, with the character passing the Difficuty check and making the most successes being the winner. Interestingly, attacks, by default, are at a D1, but, if the defender chooses to give the gamemaster a Doom point, he may choose a Defend Reaction (such as Parry against a Melee attack, Acrobatics against a Ranged attack) and make it into a Struggle.
Cinematic Rules: While many roleplaying games rely entirely upon the game master to make the encounter entertaining, Conan has specific rules for cinematic play. Experienced game masters who enjoy the freedom to "wing it" during a game might not like these rules. New game masters and those who prefer more framework for introducing new elements can now rely upon the game system to be fair and him to not seem arbitrary as he makes an encounter more challenging. Returning to the skill check, a low roll means success, so, if any dice the player rolls is a 20, then the game master can add a Complication for each 20 -- even if the roll otherwise succeeded. For example, a player using his bow may hit his target, but may find himself now out of arrows. Momentum is a currency players can use to add advantageous cinematic effects. For each success greater than the Difficulty, a player gains a point of Momentum. They can spend it on various actions, or placed in a shared pool for later use during the round. Desired Effects indlude adding +1 damage, disarming an opponent, or adding an addtional d20 to a skill test. Since a character starts with 2d20, even the most skilled character will only have two success (three if they make their Skill Focus). Characters may roll additional dice by spending Momentum, generating Doom points for the gamemaster, spending Fortune, or working together as Teamwork. A player character begins with three points of Fortune, and is awarded them for reaching milestones and other in-game accomplishments. They may be spent on a Bonus Die with an automatic roll of a one (hence up to two successes if they have a Skill Focus of at least one), a Bonus Action, etc. A character cannot roll more than three additional dice, except through Teamwork. With Teamwork, additional characters can work together as a team. Each player describes how he is assisting the leader (and doesn't have to use the same skill as the character he is assisting) and rolls one d20. If the leader scores at least one success on his roll, then any successes generated by the assistants are added to the leader's total.
Action Scenes: Any conflict is presented as an Action scene. Action scenes are divided into rounds. The length of a round depends on the encounter. Rounds may last a few seconds in intense combat, or minutes for a village raid. Each round, a character can take a single Standard Action (eg. an attack), a single Minor Action (such as running across a room or another action that does not require a skill test), and any number of Free Actions (eg. dropping a weapon). Additionally, Reactions are special actions characters can take, turning a skill test into a Struggle. Reactions include a Defend (when the defender doesn't want the attacker to use the default difficulty of one), Protect (when a character attempts to defend an ally from an attack), and Retaliate (a melee attack when an enemy attempts to make a non-attack skill test). A character (including NPC) may perform several Reactions, but the first cost a point of Doom, second two points, etc. (The gamemaster gains Doom points to the gamemaster's Doom pool for their characters, while the gamemaster pays Doom points from his Doom pool for NPCs). Players, being the heroes, usually go first, but the gamemaster can spend Doom to allow an NPCs to immediately take their turns. Surprise is treated as a Struggle, and players can still spend Fortune or add Doom if they do not succeed. Rather than a grid, the location of each character is abstracted into zones, as defined by the gamemaster. The game uses five broad range categories (Reach, Close, Medium, Long and Extreme). (Reach is defined as within an arm's reach, while Close is the character's current zone.) Each zone has various zone effects (eg. moving out of an enemy's Reach requires a Withdraw Action as a Standard Action, or risks a Retailate Reaction from the enemy), including terrain tests, which may require a Standard Action as a skill test. Terrain tests are divided into Obstacles, Hindrances, Hazards, and Cover.
Attacks: Conan has three methods of attacking a target: Melee, Ranged, and Threaten. After choosing a target, the attacker chooses a weapon (Melee and Ranged), or a method of scaring the target (Threaten). If the target chooses a Defense Reaction (paying or gaining Doom points), there is a Struggle. Otherwise, it's an Average (D1) test. If the attacker succeeds, he rolls a number of six-sided Combat Dice for Combat Damage. 1-2 causes that much damage. A 5-6 causes one damage and triggers an effect, such as Piercing or Vicious. The defender rolls a number of six-sided Combat Dice, depending on armor, Courage, cover, morale, etc., as Soak. The difference is damage, taken against the defender's Stress. If a defender takes over five damage or has his Stress reduced to zero, the defender takes a point of Harm. In less abstract terms, a Physical Damage Type would cause Stress against the target's Vigor, and Harm against his Wounds, while a Mental Damage Type would cause Stress against the target's Resolve, and Harm against his Trauma. Wounds cause an increase in difficulty for Agility, Brawn, and Coordination tests by one, while Trauma increases the difficulty of Awareness, Intelligence, Personality, and Willpower tests by one. Characters suffering four points of Wounds or Trauma become incapaciated, only able to take actions by spending Fortune. Minor NPCs generally become incapaciated or flee after one or two points of Harm. Momentum (extra successes beyond the requirement to pass a difficulty check) generated in combat can be used to additional effects, such as Bonus Damage, Confidence (additional Morale Soak), Disarm, Penetration (ignore an amount of Soak equal to twice the Momentum spent), Re-roll Damage, Second Wind (recover Vigor or Resolve), Secondary Target (another target within Reach takes half damage), Swift Action (gain an additional Standard Action with a penalty), and Withdraw (leave the Reach of an enemy without triggering a Retailate Reaction).
The Conan RPG, then, has quite a bit of "crunch" and attempts to cover every cinematic action you could have in an RPG. I've only touched upon typical combat, and the game system uses Momentum and Doom to allow players and the gamemaster to add effects to combat. Additionally, the gamemaster will spend Doom to add more challenges to the players, such as spending more Doom to select a more lethal hazard in an adventure. At this point, it's probably best to download the free Quickstart and see if the game system works with your gaming group.
Character Generation: Returning back to the core book, Character Generation is more than selecting abilities and skills. Character background is heavily emphasized, and various skills are dependent on background. The first step in character generation is determining the character's Homeland (randomly or by choice), so a character with a Homeland of Nemedia speaks the Nemedian as his Language, and has the Talent of Cosmopolitan (able to speak with other characters with the Cosmopolitan Talent; several Homelands have the Cosmopolitan Talent). Generating Attributes starts with an optional modification then randomly selects which Attributes the player next modify. The player then selects or randomly rolls their Caste, which grants two caste talents (prior background knowledge), one skill (which may be further trained), a story, and Social Standing. The skill gained adds +1 Skill Experience and +1 Skill Focus to the designated skill. For example, a Warrior Caste has Sentry and Subject as Caste Talents, Parry as a Skill, a story, and Social Standing of 1. Social Standing may have an effect on Command, Society, and Persuade tests, allowing the gamemaster to adjust the Difficulty. Stories add additional background, are randomly rolled or selected, and grant a Trait. For example, a Warrior's story may be that of "Idle Hours Guarding Cold Wars", which has the Hedonous Trait (thanks to many hours of boredom). (By bringing a Trait into play as a Complication, a player may gain a Fortune point.) Next, a player rolls or selects his Archetype. Archetypes include Archer, Barbarian, Mercenary, Noble Warrior, Pirate, Priest, and Witch/Shaman. Archetypes grant a Career Skill, Career Talent, Mandatory Skills, Elective Skills, and Equipment. For example, a Shaman has a Career Skill of +2 Skill Expertise and +2 Skill Focus in the Persuade Skill, Career Talent of Force of Presence, Mandatory Skills of +1 Experience and +1 Focus to Alchemy, Counsel, Healing and Lore, and Elective Skills of two of Animal Handling, Sorcery, or Thievery. Equipment inlcude a toughened leather jacket (Armor 1: Torso/Arms), Healer's Kit, Alchemist's Kit, etc. Then the player selects or rolls for Nature, which comes with an Attribute Improvement (+1 to a single Attribute), Mandatory Skills (+1 Skill Expertise and +1 Skill Focus to three skills), Elective Skills (+1 Skill Expertise and +1 Skill Focus to two skills of a player's choice), and a new Talent, typically associated with one of the received skills. Skills consist of a Talent Tree, in which a Talent may be a prerequisite for another Talent, and Talents can have Ranks by being taken multiple times. While Skills are used for 2d20 rolls, Talents are special abilities. The Agile Acrobatic Talent, for example, allows you to re-roll a d20 when attempting an Acrobatic test. After Nature is Education, which, again, is picked or rolled, and provides mandatory and elective skills, as well as a talent. Then, the player rolls or selects a War Story, such as "Survived a Massacre", which improves specific skills, and lets the player create the background. Character creation continues with Finishing Touches, in which the player chooses various increases in his Attributes, Skills, and Talent, as well as a Language, Fortune Points, Personal Belongings, and a Weapon. Finally, with Final Calculations, the player determines his Vigor, Resolve, starting Gold, and Damage Bonuses. The character generation chapter also has a summary table to create or roll up a character, as well as alternate character creation limitations, for less heroic characters, or characters that are part of a group.
Sorcery and Alchemy: In Conan, the concept of a sorceror isn't the guy in the second row casting fireballs. Although novices (perhaps such as player characters!) may prefer to show off and reveal their true power, more experienced and prudent sorcerors (okay, NPCs!) will prefer to hold back, creating rumors and reputations of the power, as well as allying with and controlling men of power and those they control. That being said, some sorcerors may prefer to turn to Craft and Alchemy to create Petty Enchantments, such as lotus pollen and talismans. Sorcery itself is a Skill Tree, which also includes talents only related to sorcerous knowledge, such as "Protective Superstitions", which allows you to gain one bonus Momentum per rank when in a Struggle against a spell. Sorcery itself has the prequisite of the Patreon talent, and branches into Pact -> Barter Your Soul -> Life Eternal, and Enduring -> Enchanter -> Everlasting Sorcery. Characters acquire spells through the Patreon, Pact -- and Barter Your Soul -- talents. When casting a spell, the character takes a Minor Action to Focus (particularly since the Complications are more frequent when casting spells!). He may use various items, including those which improve his social abilities, such as Persuade and Command. A spell stat block includes Difficulty, Duration, and Cost to Learn / Cost (amount of permanent Resolve to learn the spell, and amount of Resolve it takes to cast). Sorcerors can enhance their spells with Momentum spends, and some spells have Alternative Effects, such as spell reversals. Counter magic allows a sorceror who can cast the same spell to block a rival's spell with a Struggle. Not too surprisingly, with the variety of spells and petty enchantments possible, additional sourcebooks and The Book of Skelos will be available.
Equipment and Upkeep: No more tracking of copper pieces, currency is abstracted. It's still called Gold, but day-to-day expenses are covered under Upkeep. You still can't go to the local We Have Everything In Stock store and just buy what you want. The gamemaster sets a difficulty, and you can use a Society skill test (or Persuade, or even Thievery!) to locate a seller, and can use Momentum to haggle down the price, and your Renown as the seller recognizes your reputation. You typically can only attempt to obtain one of these items per Upkeep. Between adventures, besides Upkeep, players can Carouse and engage in all sorts of activities: Meet a Patron, Trade, Gamble, Engage in Rumors, Recover, Cultivate Renown, and Receive Title. At the end of their Carousing, players roll on the Carousing Events table, which ranges from seeing some grave robbers stealing from the dead, to finding a strange possession. Most of the Carousing Events feel like adventure seeds, and I wouldn't mind seeing a future supplement, of more developed encounters.
Encounters: Speaking of which, the Conan core book includes a healthy monster manual of foes for the player characters. Creature Categories are divided into Minions, Toughened, Nemesis, Horrors, and Undead (some foes have more than one category). Toughened and Nemesis creatures are mechanically similar to player characters. Minions, being more numerous and less threatening than characters, have simplified fighting rules. Enemies often come in Mobs (Minions only) and Squads (Minions lead by a Toughened creature called a Leader). The game system has rules making fighting Mobs and Squads simplified but not too abstract (eg. attacks are similar to Teamwork). Skills are condensed down into Fields of Expertise: Movement, Combat, Fortitude, Knowledge, Social, and Senses. Senses, for example, covers Insight, Observation, and Thievery. After presenting the Special Abilities creatures have, the chapter has a brief discussion of an Encounter Structure, how to design a typical challenging encounter. Creatures are divided into Mortal Foes, Wild Beasts, Monstrous Foes, Otherwordly Horrors, and Characters of Renown. I particularly appreciated the Mortal Foes section, since it provides Bandits, Bodyguards, Cultists, Guards, Pirates, Thugs, and all sorts of staple humans. Wild Beasts include domesticated animals, like Dogs and Camels, as well as foes and vermin. The Characters of Renown section has entries for Conan; Amalric of Nemedia; Astreas, Chronicler of Nemedia; Belit, Queen of the Black Coast; Valeria of the Red Brotherhood; and Thoth-Amon of the Ring.
Adventure: Vultures of Shem. The adventure opens in the aftermath of a bloody ambush of an entire army, hardly the cliched beginnings of the tavern where the party is approached by an almost random stranger or asks around for rumors. Experienced gamemasters may want to brush up on their acting skills for the uneasy soldier encounter the PCs will have. Less experienced ones or gamemasters pressed for time can modify and excise this encounter (or try the Quickstart adventure). The adventure then settles down into a more conventional dungeoncrawl against not-quite-known monsters. What I did like is how the adventure starts off distinguishing itself away from the generic fantasy adventure, and presents enough unknown (whether it be NPCs that have their own self-interests, or monsters whose seem to have a purpose) to differentiate the world of Conan. The adventure is a tad railroady (about reasonable for a premade adventure), but not obviously so, leading to a climax, which, I think, does a good job of impressing players to the world of Conan. (Oh, and if you have a player who insists on being of noble blood, they should be in for a surprise.)
Conclusion: Overall, I think the 2D20 system is a very good fit with cinematic roleplaying and the Conan universe. I started with first generation roleplaying games which tried to fit the theme and genre of a game world into its game system, and like seeing roleplaying systems which pretty much do the reverse. 2D20 still isn't far from "roll dice to hit a target number" so you should be able to still modify the system like you've been doing for other roleplaying games. The Quickstart is free to download, and contains additional content as well as makes for a player handout. I also recommend the PDF to print out the character generation chapters for the players.