not bad
The whole new loyalty can be pretty fun, of you're against the romans, just stand down until they finally rebel, and take the settlement, you get to keep your powerful roman ally, and you get a settlement. But if you're an enemy of ROme, it kind of sucks, the start out with a bunch of huge armies, so if they don't like you, or you offend them, they'll send massive armies and just wipe out all of your land.
The new horde thing isn't all that great, they're hard to manage, and it just makes the campaign last 10 minutes, unless you actually try to take a settlement.
Overall I think that Barbarian Invasion was alright, strays really far from the first game, but still alright. DOn't but it unless you find it for around $20... (>^.^)>