Think of Cities XL as a sort of spiritual successor to Sim City Societies, but with less emphasis on the people-please and more emphasis on playing God.
Now that Maxis has been swallowed by Spore and the guys who made Sim City Societies have moved onto
bigger, better things Children of the Nile, indie developer Monte Cristo is free to snap up what little market there is for city-building sims in the wake of their 2006 game, City Life (which is, you guessed it, another city-building sim).
What sets XL apart from both City Life and from the Sim City franchises is the online component. This is problematic for an early look at the game because none of what makes an online community pass or fail really exists yet. But the gist of it is, when you buy the single-player game (that you'll burn through in about four months), you can register for the online service at 5 Euros a month. The online service is really an online multiplayer mode, like an MMO along with a social networking site a la Facebook where you can interact with other people that opt to sign up for the online account.
Through the online mode, you can build a city near your friends' cities or on a completely different planet so they can't visit. But if you do that, you won't be able to trade with them - which is where the appeal of vity-building online really comes from.
Because XL features a persistent environment, you can actually work with the cities around your city to balance the needs of all the whiny townspeople that need jobs and not to die of pollution. So you could build a city that's entirely made up of amusement parks, stadiums and tourist attractions while your buddy builds a stale, totalitarian state and then just send the citizens back and forth between you so they're never really unhappy, but they continue to grind away at soul-sucking factory jobs.
In addition to sharing balancing duties, you can also trade resources with people online. So say you want to build that new stadium and you don't have enough oil or water resources to build it. You can use the site's search engine to find someone nearby your city (with the appropriate shipping capacities like airports or docks) with a surplus of those items. Then you can offer them whatever you have extra of (cement, electricity, etc.) or absolutely nothing at all and see if they'll accept a trade or just give you what you want out of the sheer goodness of their hearts.
The key to any simulated city game is maintaining balance; which is even more crucial in an online environment where seasoned MMO players already know all the tricks (twinking, gold-farming, etc.). To keep unfairness to a minimum, Monte Cristo has changed a few minor things that city-building pros might take for granted. For example, excess resources don't accumulate over time in the online mode. So if you've got 10 extra energy, you'd better spend it or trade it - or lose it when the week the ends. This keeps the online environment mostly equal without letting players that have been there the longest gain any unfair advantages. Also, special blueprints for stuff like the Eiffel Tower or that giant statue of Jesus Christ in Rio are given randomly to online players in a sort of lottery - they require a ridiculous amount of resources to build and usually give your city a major stat bonus (like attracting more tourists), so it encourages trading between gamers.
Monte Cristo is also introducing Facebook-style tie-in stuff. The singleplayer and online modes will both have Achievement-ish rewards that you can display on your XL profile or possibly on whatever social network site you use. And like Facebook, the XL site also features friend lists, news RSS feeds and ways to track the stats of your city. To go along will of this is your personal avatar - a cartoon-y incarnation that you can use to walk the streets of your own city (even in singleplayer mode) or other people's cities (although I'm told you can't do anything besides observe).
That stat-tracker will come in handy if you decide to leave your city alone for a long time. Because the online mode is a persistent environment, your city keeps on living while you're gone. So an earthquake can wipe out half your population and leave construction stalled out on your new monument and you'd never know it 'til you logged in again. But, says Monte Cristo, you'd be warned well in advance before you built over a fault line - so it's your own damn fault if it happens, really.
To me, that's what sounds the most interesting about online mode in Cities XL: there will be different planets with different conditions for you to build cities on. One planet might have absolutely no fossil fuel resources; which means you won't have to deal with as much pollution, but you'll have to look at alternative energy sources. Or another planet might have tons of fault lines but a lot of fossil fuel, so you'll have to weigh earthquake risk against drilling for oil. Singleplayer modes in many city-building games have scenarios like this, of course, but it's how you and your online buddies work around it that could be vastly entertaining.
The last thing that Monte Cristo has done to make XL stand out from its predecessors is tack on "gems" - Gameplay Extension Modules - that can be bought and plugged into your online or singleplayer game for extra mileage. The two the developer plans on releasing when the game launches are a "Beach Gem" and a "Ski Gem" where you get to play resort tycoon with either a beach or a ski slope. These gems are a more detail-oriented layer of gameplay where you can get as specific as designing a black-level ski trail or a beachside cabana with one of those bars in the middle of a pool.
That's where Cities XL will show its strength (if it has any): switching between micromanagement on the street level of your city (where you can watch citizens walk to work or get mugged) and the godlike view where little flashing icons tell you how much money a business makes or how many people have been brought to the hospital. Monte Cristo built an entire engine from the ground up to handle this view-switching and - buggy though it was in pre-beta - it looks fairly decent.
The three key problems with Sim City-style games are 1) overwhelming the player with too much to keep track of, 2) boring them to death by not throwing them enough curveballs and 3) boring them to a second death when they run out of motivation to keep building stuff. Time will tell if Cities XL address all of these problem - but I think the online mode (if it works like it's supposed to) will definitely take care of the latter two. And that first one? Well, it's the kind of thing that becomes a mark of pride for hardcore gamers ("You couldn't get past the tutorial? N00b!") so perhaps it's no big deal.
Cities XL is gearing up for a closed beta sometime between the end of this month and mid-April and is looking to release retail copies between Q1 and Q2 (sorry, not for download - you actually have to go use a CD key and stuff). Keep it here on Kotaku if you want to score a beta key.