Rome Total War was the sandbox; Barbarian Invasion is the School of Hard Knocks
The layout and overall gameplay format is the same. Lead armies, build empires, and rule the world. Yipee! There's just a catch - instead of conquering left and right like in Rome: Total War (RTW) and moving on to the next province - you have to hold on to the provinces as well. In fact, if you're one of the two Roman Factions (East and West), that is all you will be doing. At this point in history, Rome is being seiged by Barbarian Hordes - and falling apart from civil unrest. The first game I played was as the Western Roman Empire. Easy right? Ha! Joke's on me. I lost half of my provinces due to unrest with 15 turns. My empire was splintered into provinces in random places. It took many more turns for me to actually solidify my empire and not lose provinces from unrest. On top of that, barbarian hordes are everywhere - the new Horde function can do wonders if you play as the barbarian factions. They can sack cities without having to take over them - gaining more loot and destroying EVERY building in the city.
Aside from the Horde function, there are also a few new additions as well. While you can lose cities because of popular unrest, you can also gain cities from unrest. Loyalists will lead the city in revolt and hand you the key! Speaking of loyalty - it plays a big part in the game. Generals now have levels of loyalty that need to watched carefully. I lost a great, powerful army to a disloyal general who joined the rebels. Such carelessness can be heartbreaking and devastating. Also, religion plays a big role in population happiness. If you build buildings contrary to the people's religious preference - you will have unrest. Also, the governors religion plays a role - if his people are one thing and he is another, unrest can occur. Finally, there are the infamous night battles. In order to partake in one, you have to have a general with the Night Battle Ability. These battles are awesome and if the enemy general doesn't have the ability - you can have one heck of an advantage.
For those who are new the RTW franchise (for lack of a better word), I would reccomend spending some quality on the original RTW for plenty of practice. Also, those who are looking for a good fuddy duddy around game, I would not recommend this game - it's a thinking game. While it's not a brain killer - you need to be able to anticipate a lot more things and be able to handle a crumbling empire. If you don't do as the Romans did - be cocky,fall apart and disintegrate - you can build an empire that will rival even the mighty Roman Empire.