Like both previous Total War expansion packs (Shogun's Mongol Invasion and Medieval's Viking Invasion), Barbarian Invasion injects dynamism into Rome Total War's static campaign map, with new mobile factions. And happily, it goes further still, offering a wide choice of campaign types.
Will you take up the management challenge of an already-large empire, complete with unhappy populace, porous borders and expensive armies? Or attempt to turn one city into two, then three, then 20... then march on Rome?
Or, will you join the terrifying horsemen of the Huns or Vandals, free to charge across the steppes and settle where they wish? Already Barbarian Invasion is making us feel warm inside, and we're still on the menu screen.
The fundamental Total War mixture of turn-based strategy map management and real time army-level battles works as well as ever, and in this regard Invasion offers few changes to something that's certainly not broken.
The campaign map, meanwhile, plays host to an army of differences that'll pose tough challenges to those who've mastered the original.
This covers the same area: from the Scottish borders and central Russian plains to modern-day Saudi Arabia and Morocco. Now, however, there are fewer settlements and thus fewer territories.
More space in between means you'll need to be more cunning than ever about positioning armies to defend borders.
Barbarian Invasion deliberately attempts to distinguish the campaign experience for each faction, too. Whereas with the original, the challenge of simply managing settlements and your slowly expanding empire was pretty much the same whichever race you played, now you'll face challenges unique to each culture.
As a Roman leader - of either the Western Roman Empire or the breakaway Eastern lot, based in Constantinople - your generals have a new characteristic: loyalty.
As you start a Roman campaign, many of your settlements will be at immediate risk of revolt because of overcrowding, distance from the capital, and any other reason those pesky rioters can think of.
Generals with low loyalty may band together and lead a fully fledged rebellion, forming a new faction and yet another enemy for you to face.
Luckily for leaders of non-Roman factions, loyalty is not an issue - but the addition of religion brings yet another factor into the equation.
A settlement's populace will have its own religion, but unhappiness may result if this is at odds with the ruler's main religion, or with that of its neighbours.
While Rome's campaign could become static, a Barbarian Invasion campaign is packed with uncertainty and menace. Where are the hordes? Will the Huns attack my neighbours or me? Can I take advantage of a Roman rebellion? When is the right time to settle? The replay value is phenomenal.