This campaign shares many features with Dungeons & Dragons, there are lots of monsters, plenty of magic, the Core Character Classes of Dungeons & Dragons are all there, the ranged weapons are a bit more advanced that the standard ranged weapons of Dungeons & Dragons, because this is the age of gunpowder, it is also the age of exploration, and the age of piracy.
If you ever seen a Pirates of the Caribbean movie that would fit right into this setting Early Modern characters share some features with Dungeons & Dragons and some features of D20 Modern. We use the Defense rules of D20 modern, armor is only half as effective against gunpowder weapons as it is against other armor types. Characters develop combat reflexes which serve as a natural defense bonus increasing with level at about half the rate of the character's Basic Attack Bonus, thus if a character has a BAB of +2, his Defense Adjustment will be +1 before he puts on any armor or takes his dexterity adjustment into account. A 1st level Fighter for example will have a BAB of +1, and a Basic Defense Adjustment BDA of +0. Fractional amounts are rounded down. Let's just call the Defense Score in D20 modern AC to avoid confusion.
On the character Sheet there will be the AC score, the Touch score which is Armor class minus the Armor Rating AR of the Armor worn, the Flat-footed score which is Armor Class minus the Dexterity Adjustment, and the Gunpowder Score which is the Armor Class minus half the Armor rating of the Armor worn rounded down. Aside from this little mechanic everything is the same as in the Dungeons & Dragons 3.5 Core rules.
Ships are more advanced, they cross oceans, have better navigation, and typically come armed with cannons, there is the Old World and the New World. Socially the Old World is set up much like the standard Dungeons & Dragons campaign setting, the melee weapons are much the same, gunpowder weapons have replaced crossbows shortbows and longbows, one thing gunpowder weapons aren't is quite, if you want to do a sneak attack, bows still have their uses. Firing a musket pretty much alerts everybody in the enemy camp that they are under attack. For a dungeon setting, it is useful to use melee weapons, or bows as the walls of the dungeon will muffle the sound a bit, but fire that musket and everyone in the dungeon will pretty much be onto you.
Magic works the same, money and treasure are the same as well. What do you think. Is there anything to add about this?