I don't do many video game reviews on this site; there are people who play more games and do a much better job of it than myself. Still, I'll occasionally write them, and when it comes to Sid Meier's Civilization, I'm always willing to offer an opinion.
[Just a quick note: if you've never played the Civilization game or have any idea what the game is, most of this review will probably be gibberish. It's an expansion, so this review assumes you know how the original game operates.]
I've been playing Civilization since the very first version came out way back in 1988; I've eagerly anticipated each new edition, with new features, new graphics, and a much more interesting gameplay. So far I haven't missed any.
For those who aren't familiar with the brand, Civilization puts you in charge of one of history's greatest empires--say, the Romans, or the Russians, or the Assyrians--and you guide them through history, discovering technology, building cities, and conquering neighbors. The latest edition, Civilization V, came out in 2010, and has had two expansions: Gods & Kings (released in 2012) and, now, Brave New World.
One of the major criticisms of Civ V when it first came out is that it was too simple: compared to previous Civ games, where each new edition added new features and more depth, Civ V seemed like a step backwards. (There were also some obvious balance issues.) In retrospect, it was certainly a true claim but was also not necessarily a bad thing; the game get new players to play, and slowly added content until the current version of the game is just as robust and strategic as any of its predecessors.
Anyway, after Gods & Kings added espionage, religion, and a better City State system, it more or less brought Civ V up to speed with Civ IV (save its awkward corporation mechanism). So when the new expansion was released, many people were wondering what changes could be made that were new and fresh aside from the usual additions (such as new civilizations and new wonders).
The game overhauls quite a few things in the game, but the new content boils down to three things: a new Ideology system, a new Trading system, and a World Congress.
Ideology System: Previously, the "policy tree" system allowed players to purchase new policies that would grant benefits to your civilization; many of these (such as Piety and Rationalism) were mutually exclusive. The "modern" idologies--Freedom, Autocracy, and Order--were also mutually exclusive but otherwise worked like regular policies.
That's all changed now. You now explicitly must choose one of those three Ideologies once you hit the modern age (or build enough Factories). The "policy tree" for these three branches are now greatly expanded (fifteen (!) policies instead of the usual five). In addition, your ideology is in direct conflict with the others. Players may try to export their ideology through a new system called "tourism." Basically. the more people that visit your ideology (and see how awesome it is) will affect relations, and may eventually cause cities to flip. (Generally speaking, tourism acts as the offense and culture the defense.) It also overhauls the Culture victory condition: instead of winning by filling out five policy trees, you win by exporting your tourism a sufficient amount to all other civilization in the game.
A part of this new system are Great Works--Music, Art, and Writings. Instead of simply having a "Great Artist" there are three distinct Great People. You can use these leaders to create Great Works, install them in your buildings, and produce culture and tourism. There's a system where you can combine different works in various ways to create bonuses. While you still produce culture the old fashioned way, the output is diminished and instead make up for it by collecting these Great Works. And finally, once you discover Archeology, various archeological digs are found throughout the map, and you can send a new Archeologist unit there to dig it up (where they can be installed just like great works).
Trading: Instead of generating wealth through tile yields, you now generate wealth through creating trade routes. You can build either Caravans or Cargo Ships (land and sea, respectively). Once built, you select a destination city. The trade unit will them move between the two cities and generate a certain amount of money--and, depending on the situation, also religion and science. (There's plenty of other special abilities that generate even more yields.) After 30 turns, the trade route stops, and you can either do it again or pick a new destination. While you still collect some money via tiles and other items, the majority of your revenue comes from trade routes. Your trade routes can be disrupted, so they must be protected.
World Congress: The previous diplomacy system was pretty simple: someone builds the United Nations, and then everyone votes every 10 turns to see if anyone wins enough votes to win the game. it's now much different.
A "World Congress" convenes once one player 1) knows the Printing Press and 2) has made contact with all other nations. Every so many turns (and when certain Age qualifications are met), two proposals are made (the host and the player with the next highest number of delegates). Each player is assigned a certain number of delegates (generally corresponding to the number of City States they are allied with, but could also be for other reasons), and they may allocate those delegates to vote "yes" or "no" on a wide variety of issues. This includes winning the game via Diplomacy, but also includes things like embargoes, outlawing a luxury resource, hosting a World's Fair, and so on. (It's similar to how Civ IV did it, but it's a lot more comprehensive.)
There are, of course, all sorts of tweaks and additions, such as new civilizations, new wonders, new buildings, and so on. But the three things listed above are the main changes to the game.
So, what is the verdict?
All in all, it is a good addition to the game itself. It certainly adds a significant amount of content to the game. All three of the new systems listed above are done very, very well. The Ideology system makes a lot more sense now. The World Congress is fun; the list of proposals is pretty exhaustive and you actually get to wheel and deal with other leaders. The trading system also makes a lot more sense, and it's pretty interesting to look at all of the different destinations, all of which produce different outcomes. All three of these major changes now make the late game significantly more fun; the biggest criticisms of the franchise has always been the lackluster end game, as the thrill of expansion and exploration makes way for boring accounting. The trade network, the ideologies, and the World Congress inject a lot more fun into the second half of the game. And it's pretty seamless--while it's obvious that two of the three don't deliberately kick in until late in the game, you don't notice it because it makes sense.
Probably the most welcome change is in the AI. The AI is just as scatterbrained as always, but now that there are trade routes and the World Congress to deal with, the consequences of war are greater. As such, there are less outbreaks of war. I'm a builder, not a fighter, so I like this change; however, I'm sure many people do not. (To compensate, the barbarians are smarter and more aggressive.)
Edit: I wanted to mention this in the original post, but I forgot. There's a bit of an AI quirk; either the formula changed or other things changed and they didn't compensate for it, but the "Warmonger" penalty seems to be too extreme. This was a penalty if the AI players thought you were capturing too many cities and thus was too aggressive. The way it sits now is you could capture one city in, say, 2000 BC and in 2040 they'd still be mad. It's pretty obnoxious and probably should be fixed.
And just a few notes about the content: there are plenty of innovative new civilizations, such as the Assyrians (steal a technology when you conquer a city) and Indonesia (you get three unique luxuries that can be traded away). Probably the most notable new civilization is Venice; they cannot build any new cities and cannot annex any conquered cities; all they can do is create puppets for the cities. As compensation, their trade revenue is doubled. It's certainly different, and given the core mechanics of the game it works remarkably well. There's also a host of new Wonders; most of them deal with the new Great Works system. Since the three ideologies are combined into one system, that let Piety get split up into Piety and Aesthetics (faith and culture, respectively) and Commerce gets split into Commerce and Exploration.
And as mentioned above, two of the five victory conditions are different: Culture requires that you export your Tourism rating to a certain level to all other civilizations, and Diplomacy is part of the World Congress. This, of course, changes a lot of strategies. The culture system is probably the biggest question mark; while there's still a "closer" bonus for finishing a policy tree, there's no inherent drive to do so now that it's no longer a victory condition.
That said, there are a few changes that...well, they aren't bad, but
could take some getting used to. Science costs now increase as you build
more cities, which discourages rapid expansion. I kind of like this
change, although it gets pretty drastic. I would prefer that it be toned
down, but it's not a dealbreaker.The Great Works system is very awkward; it's hard to know what goes where and what would make the best combination. And splitting up the Great Artist into three separate Great People seems to clutter things up with little benefit. It seems like a lot of work and detail to accomplish something the old system managed to do OK with. I don't hate it; it just seems a little sloppy. The whole Tourist concept works, but it's not documented very well and it's not easy to grasp.
I'm also sure there are plenty of balance issues to work out as well. Right now, it seems a lot easier to generate Great People (possibly to make up for the fact that there are three Great People now?) which throws off some things. There are so many Wonders now it's impossible to hoard them all--which is probably a good thing, although it makes the number of wonders you build and have to abandon much higher. Money and Culture are tight in the early game and become almost embarrassingly plentiful in the end game. These aren't bad changes, but they are different enough to the previous game that it will take some time to adjust to it. The game also seems to take much, much longer;my first victory was a Time Victory, which I haven't done in years.
Is it worth the $30 retail price? It's tough to say--you're getting a similar experience as before, so I'm not sure if that's worth half of the cost of the original game. (At this point, the game, expansions, and DLC exceed a hundred bucks if you pay full retail; I'm not sure if it's worth that or not. Thankfully it's very easy to not pay pull retail.) But if you are fan of Civ V, it's definitely worth getting; while it's a similar experience it's different enough to keep you engaged.