* Barbarian Hordes - A barbarian faction can flee en masse from an attacker and take its entire people in search of a new homeland. When a faction loses its last settlement the entire population can move as a series of horde armies. If - and when - the faction manage to conquer a new homeland region, the people can again settle and begin life anew. While a faction is on the road it cant recruit new units other than mercenaries, but it doesnt pay any upkeep on its armies. Hordes are a get out of jail card for some factions facing defeat - or they may just get hacked to pieces as they run!
* New Units - New factions means new units! In fact, almost every unit in BI is new. This means that there are plenty of new tactical tricks to discover, strengths to play up, and weaknesses to exploit! Every faction in the game has a signature unit that is unique to them, such as the axe-throwing Francisca Heerbann of the Franks to the ultra-heavy Sassanid Clibinarii cavalry. Even apparently familiar units have been revised.
* New Special Abilities - Some units in the game have new special abilities. The Shield Wall allows barbarian elites to lock themselves into a defensive stance and withstand frontal attacks. The Schiltron is a defensive hedgehog formation for spear-armed troops - great for withstanding cavalry, but very vulnerable to missile fire. Swimming allows light troops to cross rivers and flank defenders who think they are safe at one end of a bridge or ford!
* A modified technology tree - allows barbarians to build and expand larger settlements. It also includes new buildings to reflect the changed importance given to religion at this time in history.
* A new campaign map - Europe and the Empire have changed after 350 years of Roman rule since the end of the main Rome: Total War campaign. The new map reflects the shifts in population and wealth that have gone on.
* Religion - is now an important factor. Christianity has become the dominant religion of the Empire, but its your choice whether or not to revert to paganism in the hope that this will bring victory. Barbarian factions can convert, opening up new parts of the technology tree in the process.
* Generals - can now be recruited as well as adopted into the family. There are also new vices and virtues as well as ancillary characters for generals retinues.
* Rebellions - can now flare up into full-fledged civil wars. Your generals can decide that they would make better kings or emperors than the current rulers and take matters into their own hands!
* And goodbye to the Senate! That old favourite enemy of Rome: Total War players everywhere is now a toothless talking shop with no power over the fate of the Empire. Instead: worry about the Huns!