There are those who feel that Civilization V, as it was first released, was a little thin. The game's first expansion, Gods & Kings, addressed some of that criticism. Its second, Brave New World, transforms the game into one of the best the PC has ever seen.
It does the things you'd expect from a major expansion. There are nine new civilisations, new units, new buildings and new wonders.
But then it goes and does so much more, and does it in a way that, when you look back on 2010's original effort, you'll think you're now playing the sequel.
Let's start with the biggest and most important additions. Brave New World completely alters the way culture, diplomacy and trade are handled. Culture is no longer simply a modifier that expands your borders, and trade isn't just a magic money connection between two cities.
Instead, they're now a part of the game world. To establish trade routes, you need to build land (caravans) or sea (cargo ship) units and have them actually move to the cities they're trading with. This doesn't just see money change hands, but is also a new (and effective) means of spreading other things, like religion. These units are always on the map, can be tracked, and in times of war attacked and seized by you (or your enemies).
The idea of culture also gets its own land units. A new introduction to the series, Archaeologists, appear later in the game and are able to travel the world visiting special sites, which in a neat touch are based on ancient in-game events or locations like old battles or barbarian camps. These units can either build landmarks commemorating the event or, if a site is outside your territory, you can make like the British Museum and steal the stuff, putting it on display back home.
Great Artists have now been broken down into three types: Great Writers, Great Artists and Great Musicians, with all three able to attach their works to a city like a perk, increasing its cultural worth. The Great Musicians can even go on tour, similar to the religious missionaries, travelling the map spreading your culture and helping increase your "tourism" score.
Below is a video showing this sort of stuff in action.
"Tourism" isn't the greatest term for what's really a new tally measuring your cultural might. The more wonders you build, the more great works your artists put on show, the higher this score gets, and later in the game this gets important.
Why? I'll get to that in a minute. First up, though, the way all these units work is fantastic. Civilization has long offered you the possibility of a cultural victory but it's always been the most boring path available. Military action always gave you battles to plan, units to move, things to do; the pursuit of cultural victory, meanwhile, left you doing little but hitting "next turn" 500 times in a row.
Now, however, you've got something to keep you busy! Which is important not just for cultural players, but for all players in the mid-game lull, once the races for religion and expansion are over and before the modern world's military showdowns have begun.
Archaeologists can sneak around raiding tombs, musicians can tour the land spreading culture, your trade empire can reach out and literally touch every corner of the globe. You're almost as busy as a more hostile player, but with none of the bloodshed.
There's a point to this. Get your culture score big enough and you'll start influencing other civilisations, whose leaders will solemnly approach you and tell you their people are now "wearing your blue jeans". Influence enough civilisations and you'll be granted a cultural victory.
You can compare and compete with civilisations pursuing other means of victory via another big new feature, the World Congress. Beginning in early times as an infrequent get-together and eventually evolving into the United Nations, it's a way for every civilisation in the game to meet and enact global laws and policies, as you'll see in the video below.
Have an enemy who's more powerful? You can try and enact a trade embargo, hitting their back pocket. Industrious and/or after some cultural benefit? You can elect to hold Civilization's versions of the World's Fair and Olympics. Peaceful players can even try and get global laws passed taxing standing military units, which can cripple larger powers.
Motions live and die on the number of votes they receive, but what's cool is that you can lobby behind the scenes - via the regular diplomacy screen - to assemble voting blocs. I had an instance playing as Japan where I was a global superpower, but I was in some ways too powerful; other civs frequently ganged up and tried to cripple me by blocking my own proposals and enacting others to restrict me.
There's a bigger point to this as well. Late in the game, votes can be taken to elect a "world leader". If you can wrangle enough of the votes to win - and it takes a lot, so you'll need to be smart - you'll be granted diplomatic victory.
All of this helps lend the expansion some feelings the series has long been missing: the sensations of community and power. Thanks to Civ V's wonky AI, alliances and friendships often felt artificial and fickle; now, while they're still far from perfect, the formality and importance of the World Congress really brings everyone together.
Power, meanwhile, is reflected in the way you can see and control your new units. It's one thing seeing your bank balance trickle upwards, it's another to get to see your trade network in the flesh. It's also supremely satisfying to be a global superpower at the World Congress, able to exert your will over other players.
Being in the top position of an arbitrary points leaderboard had long been the game's only way of measuring success, reliant on size and strength, but now, even the smallest civs can work their way to the big table through culture, diplomacy and trade.
Note that I've really so far only touched on the game's biggest and most important additions. There are plenty more. Your civilisation's religion is joined late in the game by a chosen ideology (essentially democracy, fascism and communism), which is not only a further means of alienating/allying with other civilisations, but also of customising your strengths, as like with religion your ideology lets you augment your civilisation with bonuses and perks, some of them - like the ability to double your output of strategic resources - ridiculously powerful.
There's also a new civilisation that's a radical departure from the way the game is normally played. Usually, a new faction simply means a few new units, but the addition of Venice to the game is a great challenge for seasoned players, as after you establish your capital you're forbidden from building or annexing cities. You can only create puppets from conquered enemies, meaning in most cases you're reliant on diplomacy and trade, though if you really must expand your Great Merchants can buy entire city states.
There are only really two areas that Brave New World fails to impress. The first is the way trade actually affects your growth; I found that even on a few different difficulty settings, by the time I hit the industrial period I was making more money than I knew what to do with, which made things a little too easy.
The other is sadder, at least on a personal level. As someone who still feels that Civilization II's Second World War scenario is one of the best strategy games ever made, the two scenarios included with Brave New World underwhelm. The game's lack of stacking makes the US Civil War scenario a bizarre exercise, while the colonial Africa map is an overly-complicated mess.
But, um, whatever. I thought Gods & Kings had done enough to turn Civilization V into the best game in the series. The advances made here, turning trade, diplomacy and culture into things you can actually manage, go so much further. In addressing some of the series' longest-standing issues, such as long periods of inactivity and less appealing pursuits of victory, Firaxis have turned Civilization V into one of the best strategy games of all time, regardless of how you want to play the game.