Civilization IV is a turn-based game in which the player builds an empire from scratch. All standard full-length games begin in 4000 BC with a settler that builds a single city. From there, the player expands an empire while contending with rival nations, utilizing the geography, developing infrastructure, and encouraging scientific and cultural progress. By default, players can win the game by accomplishing one of five goals: conquering all other civilizations, controlling the majority of the world's land and population, being the first to construct a space ship capable of colonizing Alpha Centauri, increasing the Culture ratings of three different cities to "legendary" levels, and by being declared "World Leader" after first becoming Secretary-General of the United Nations. If the game's clock runs out (by default in the year 2050 AD) with none of these goals fulfilled by any nation, the nation with the highest score is declared the winner.
- A new category of Great People known as Great Generals
- The ability to institute vassal states
- Eight new scenarios
- Six new civilizations playable in single-player and multiplayer
- Ten new leaders (Including new leaders for existing civilizations)
- Three new leader traits (Charismatic, Protective and Imperialistic)
- Unique buildings for each civilization
- Three new wonders
- New units, resources, and improvements
- Core gameplay tweaks and additions
- Inclusion of all patches released for original Civilization IV.
- 10 new civilizations
- 16 new leaders, one for each new civilization, 6 for existing civilizations
- 25 new units, 18 buildings and new technologies added primarily to the late game
- 11 new scenarios
- 6 new Wonders of the World
- New diplomatic resolutions through the United Nations
- Corporations: A new gameplay feature, similar to religion allows players to create corporations and spread them throughout the world. Each corporation provides benefits in exchange for certain resources.
- Espionage: Now available much earlier in the game, this expanded feature offers players many new ways to spy on opponents, stir citizen unrest and defend their government’s secrets.
- Random Events: New random events such as natural disasters, pleas for help, or demands from their citizens will challenge players to overcome obstacles in order for their civilizations to prosper.
- Advanced Starts: This new option allows the player to start the game in any era by purchasing components for an already-developed nation.
- Expanded Space Victory: Obtaining a space victory is now more difficult and requires more strategy and decision-making than before.
- Expanded Diplomatic Victory: It is now possible to achieve diplomatic victories much earlier in the game, and to defy resolutions.
- New Game Options: Beyond the Sword offers various new game options, like new world-types and the option to play any leader-civilization combination.