Welp, I played through 51 out of 100 turns worth of the Civ IV tutorial that is part of the demo, and let me tell you this: It's incredible. In no way is this game inferior to the original Civilization running on my Mac LC emulator in black and white. It's got settlers, warriors, irrigation, mines, roads, shields, gold, science vs. wealth trade-offs, multiple civilizations just beyond "the fog of war", barbarians, the whole slew!
If I'd never played any other version of Civilization before this one, well, WOW. The game's incredible.