1. Voodoo-esque magic: All practitioners are in exotic, dangerous locations pursuing wicked goals, hiding from the witch-hunting mobs, or turning their backs on society. Abilities include laying tricks (spell-trapping a place), creating hot foot powders (to drive your enemies out of town), and . Of course, there's always the chance for your spells/tricks to go awry.
2. Boneman's Kingdom: Dying is a big deal in this campaign, and the beginning of a whole new adventure. Down in the "boneman's kingdom" you can adventure alongside your living allies as a wraith, but your adventures always reflect an internal battle within your heart & mind. The boneman's kingdom can be physically visited, usually when a wicked thief or demon tricks you to enter. Though people fear death, it is not because they won't return, it's because their soul becomes vulnerable to theft, manipulation, enslavement, and blackmail. In fact, some priests specialize in making sure that the dead don't get resurrected, as one can buy oneself back from death...at great cost. There are no detect undead spells, and undead (zombi) are very hard to identify.
3. Yocals: People are insular and superstitious. There are no "save the kingdom" missions. Most PCs will be either exiles, rejects, enemies, or rejects of their society. There are no royal roads, postal systems, or vast empires. This world is a conquering lord's nightmare: "You mean to collect tribute from the village I've got to send my scouts through Dimroot Swamp, risking mosquito blindness and demoncrocs, then undercover through territories controlled by a hobgoblin warlord, and once they've reached the village, they'll have to convince the pitchfork-wielding villagers they're not demons?"
4. Central civilization: There is only one major city, and it is the seat of religion, culture, enlightenment, and paladins. It is kind of like heaven on earth, with a twist, inspired by "Utopia" by Thomas Moore. The farther away one gets from this capital, the more rural, rugged, idol-worshipping, and backward the villages get.
5. Invisible gods: The people never see their gods. The closest they get is once a year, when the temple priests parade the god's shrouded palenquin/statue through the city. Priests are rarely faithful servants, and more often seek to manipulate the gods to do their will through the knowledge of ancient True Names.
6. Druid tribes: Barbaric tribes led by druids seek to restore the Goddess religion, and use guerilla tactics against their foes. Many are afflicted with a minor form of lycanthropy, but learn how to control their condition. Considered enemies-of-the-state.
7. Wicked prince: A prince was born who prophesy foretold would destroy the kingdom should he ever have sex. The prince, fearing that he should fall to his lusts, attempts to make a strict Puritan society, punishing women severely for any show of beauty. He has created a harem of man-slaves, who plot his assassination. Unfortunately, the prince is hard to kill, having bathed in the blood of the phoenix, granting him invulnerability.
8. Shades of grey: Everyone has dark secrets in this campaign (in fact all PCs choose one at first level). Sample dark secrets are "mentally ill loved-one" and "marked by dark lords". Conflicts are never black and white. Whether it's intense competition, a misunderstanding, unfortunate happenstance, debate on the best way to solve a problem, or good intention gone awry, conflicts are much more personal, escalate quickly, and often will end tragically (what if the villain you're fighting has a dark secret of a missing son.... only to discover at his death it's you!).
9. Daring do: Campaign incorporates the stunt rules by Lizard, and the daring stunts from Adventure! d20. Heroes can attempt amazing manuevers of agility.
10. Amazing astronomical events: Think aurora borealis. For several years, the night sky has become very interesting, with shimmering curtains of light, lightning moving in strange directions, odd shaped clouds, meteor showers, etc. Only the most skilled voudanistas and the people in the central city know the truth: The Dream World is going to collide with the earth, spilling its denizens into known reality. And it's much closer than we thought.