There's a reason why the Civilization series is one of the oldest and most beloved strategy game dynasties you can find on computers today. The addictive turn-based games draw on real-world history and offer open-ended gameplay that lets you conquer the world as a warlord, diplomat, or scientist. They also have a disturbing tendency to keep you up late into the night taking "just one more turn." Civilization IV was an award-winning new chapter in the series in 2005, and last year's Warlords expansion pack helped make a good thing even better. And now, the Beyond the Sword expansion brings even more improvements to a solid foundation. The new game adds plenty of features that breathe new life into the core Civilization gameplay, and also tosses in lots of new content in the form of new modifications ("mods") and custom scenarios to play through. Not all of the expansion's additions are clear-cut improvements, but if you're a Civ fan, you'll find that Beyond the Sword will give you plenty of reasons to get hooked all over again.
The core game of Civilization IV starts you out with a national world leader who possesses a few advantageous "traits" in various specializations (military, scientific, economic, or cultural) and starts you off at a specific era in history to conquer the world through force, science, economy, or culture. Beyond the Sword adds new world leaders to play as, as well as new leader traits that help expand certain strategies, such as the "protective" trait, whose defensive properties aid players who seek to conquer the world using scientific research to win the space race, and the "imperialistic" trait, which greatly speeds the production of "settler" units that can be used to stake new claims in uncharted territory by building new cities.
The expansion also offers new options to create customized games to your liking, such as the handy "advanced game" mode, which starts you in a game about 10 turns in, unmolested. This helps get you into the game's truly interesting action (beyond just building your first city) faster. You can also opt to use the expansion's new events system, which randomly triggers various events that take place throughout the game. Many of these events aren't all that important, but some can have farther-reaching consequences, such as changing your standing with a rival nation. If nothing else, they add some welcome variety to the usual turn-based Civilization pace, and they can be toggled off if you don't care to use them in a custom game.
Beyond the Sword's more significant in-game features are espionage and corporations, which are interesting additions that bring even more variety to the game, though they aren't always practical or all that useful. Corporations essentially act like late-game religions; that is, just like with Civ IV's original religion system that let you spread religion from city to city, the expansion's corporations can spread around the world--though in this case, they focus on various economic specialties like cereal mills, mining companies, or even a chain of sushi restaurants. When used properly, they can provide powerful economic advantages, but they're balanced out by their substantial maintenance costs, even though these can only be accessed much later in the game.
Espionage, on the other hand, doesn't figure quite as prominently into the average game of Civ IV. This new feature was supposed to give you exciting new options with the new spy units, which can scout out other nations and perform undercover operations like gathering additional info on your rivals or stealing their technologies. Unfortunately, spies don't provide enough advantages to justify constantly pumping them out and sending them to the four corners of the world, since they frequently get discovered and captured before they can even get to enemy territory. In many cases, you may find yourself just skipping out on the turns it would take you to research espionage improvements to focus on your scientific research or military might. Fortunately, the expansion offers plenty of other accoutrements for the game's core strategies, including a fistful of new units, new combat tweaks to better balance siege combat, and an expanded space-race game for technophiles that makes a space-race victory not just a matter of who builds a shuttle first, but who builds the best and fastest one.
If that weren't enough, Beyond the Sword also packs in six new one-off scenarios plus five playable mods created by both in-house Firaxis developers and the fan community. Not all of the content is stellar--some, like the futuristic zombie-hunting scenario "Afterworld," don't quite hold up, though others, like the epic "Rhye's and Fall of Civilizations" fan-created mod, are excellent and provide a fresh new coat of paint to the core Civilization gameplay. Even though some of the mod content has been available publicly for some time, it's definitely convenient to have everything wrapped up in one place, and all the extra content will keep you busy for a good, long while--as you'd probably expect from the second expansion pack to a game that's infamous for stealing your free time.
Beyond the Sword's additions are primarily to Civ IV's core gameplay, so the expansion doesn't make a huge leap forward in terms of graphics or sound. But that's just fine, since the game's thematic, instrumental score continues to work well with the game, and the new graphics (in the form of new mod units and movies, as well as new leaders with new animations) fit into the game without a hitch. Unfortunately, Beyond the Sword doesn't address the somewhat cluttered interface that Civ IV had; in fact, it adds a bit more clutter with the event system, which pops up windows in the upper-right corner and logs them in a scrolling box at the top-center of your screen. Some of the clutter may still seem intimidating to beginners, but this expansion isn't necessarily for people who have never played Civ. And if you have, you shouldn't have many problems picking up the nuances of the interface, and you'll probably be too busy trying out all the new gameplay features that fundamentally change, and in some cases, revitalize, an already-classic game. Though not all of the additions in the expansion are perfect, there's plenty of new stuff in Beyond the Sword for Civ fans to play with, and plenty of reasons to dive back into the game and start taking "just one more turn" all over again.