The Dark City Expansion plays with Citadels, the popular card game designed by Bruno Faidutti. Before I start my explanation, the reader should know my bias. I love Citadels. It is one of the first games I purchased and also one of my favorite to play. Consequently, if you are only a lukewarm Citadels player, you may want to take my comments with a grain of salt. I own the original German version, Ohne Furcht Und Adel, since the English version had not been published when I purchased the game.
In the Dark City Expansion you receive:
1. A full set of all the character cards in the game including the alternate characters (witch, queen, etc.)
2. Player aid cards that go over the turn sequence.
3. A wooden king marker to keep track of who chooses the character roles first.
4. Brand new purple district cards.
I will go over these individually.
Full Set of New Character Cards
For me, these character cards were the reason to purchase the expansion. That is because they are not included in the German version of the game which I own. I was more than upset when the English version had these cards but there was not a German expansion that included them.
If you have the English version of Citadels, however, you may be upset to have spent your money on these. It is possible that you have played the game so often as to render your original character cards marked, but I doubt it. I have played a great deal but still use my original cards. Odds are, you will not be impressed with this portion of the expansion.
Player Aid Cards
These are perhaps nice for the first time player but are hardly necessary. A listing of what individual character abilities are would have been more useful as the player turn sequence is not all that difficult to comprehend.
Wooden King Marker
This is also nice, if unnecessary. The card marker in the German version or the cardboard tile in the English version were sufficient for the purpose, but the marker is wood and more tactile. Wooden components are a classy touch.
New Purple District Cards
For those of you who are buying this expansion to go with your English version, this is the reason to get it. There are enough new cards here to add a new thrill to the game. Several of the cards are, in my opinion, vastly more powerful than the majority of the original purple cards. In addition, they are simply more clever.
One, apparently the result of a fortunate misprint (see Bruno Faidutti's website), is called the Poorhouse. It costs nothing to play (and as a result gives no value to a city) but offers a powerful ability. Another lowers the building cost of all purple districts. The list goes on, and the buildings are great.
Some have worried that all the new districts will unbalance the game. Bruno Faidutti has recommended (again see the website) that you simply switch a couple of the old districts out for a couple of the new ones. That seems to maintain the balance well. You are by no means bound to this however. You can throw them all in if you wish.
This expansion is definately worth it if you own the German version of Citadels. It gives a powerful new addition to the game that will keep it novel for a long time yet.
If you own the English version, you probably need to assess how much you love playing Citadels. If you at least consider it a good game and it gets play time fairly often, then I would suggest getting it. Tack it onto a large order so that you maximize your shipping efficiency; it isn't like the expansion is extremely expensive.
As Bruno Faidutti points out, the Dark City Expansion isn't meant to be a fundamental reworking of the game - only something to liven up an already great game. For a complete reworking, you may want to try Fist of Dragonstones by Days of Wonder.
The current English version of Citadels from FFG already includes the Dark City expansion.