If your computer is powerful enough, you'll really see the graphical jump: waves roll lazily across the ocean; horses stomp on the ground and eat grass; military units adjust their gear. It's a living world with new environment
squares hexes that have different terrain depending on which continent you're viewing. Think: Wide sweeping plains, majestic, snow-capped mountains, dense forests, lakes full of slowly oscillating water, and more. This is why your graphics processor and CPU are going to need a real head of steam.
You'll also see full-motion video of the other leaders and be forced to observe their body language; however, you won't be able to see the on-screen modifiers that communicate things like "Japan is pretty pissed off at you." In our sample game, we approached George Washington and offered him some "luxury resources" to keep him sated, but he wasn't happy with them. Thus, war was declared on the Americans. Ol' Cherry Tree himself responded by taking a step forward, lowering his voice and saying, "You have mistaken our love for peace for weakness. You shall regret this!" Wooden teeth must make you pretty cranky.
City-states are also being introduced as cities that don't represent an entire Civilization, but can help or hinder you along the way. They won't attempt to grow beyond their own borders, but you can negotiate truces with them, ask them for help, or squash them and just add their city to your growing empire without the need to expend a Settlers unit. But your opponents can also do the same. In our demo, the player played nice with a nearby City-state, offering them a one-time gift of gold. As a thank you, they would send a new unit our way every now and then. It's a nice way to get new units without spending the resources on them.
Also new will be a full-fledged world builder, and full support for modders (thanks in no small part to lead designer, and former Civ modder, Jon Shafer). There will be a database of mods that you can access through an in-game web browser; you can also vote for mods or even cruise through the forums while waiting for other players to move. An in-house joke at Firaxis is that players will be able to load up and play Sid Meier's upcoming Facebook-based Civilization Network while waiting on other players to move.
Supposedly the team learned a lot about streamlining Civ V's controls by looking back at Civilization Revolution -- though that doesn't mean Civilization V will be coming to consoles. We asked if it would possibly be coming to the Mac, an especially timely question given Monday's hot and steamy announcement, but a 2K representative told us, "We can't comment on that right now." Which smells a lot like, "We'd better start work on a Mac version pretty darn quick."