Without going into too many details, Dominion is a medieval-themed deck-building card game designed by Donald Vaccarino. The base set was released in 2008 and received a bunch of awards. A total of 8 expansions have been following, released every 6 months. Most of the cards of the 8 expansions were already designed and bundled in sets since 2008.
In Dominion, the optimal strategy depends on which cards are already in your deck, what the other players do, what cards are available to add to your deck, and a small amount of (somewhat controllable) luck. The game has been so carefully tuned and playtested that some reviewers consider it too safe and overbalanced, overdesigned and overdeveloped. Dominion's balance is so interesting that it deserves an article in itself.
Looking at the complex interactions between cards, Dominion reminds of Magic the Gathering. For example, expert players talk about engines, a concept similar to Magic's deck types, but (I'd say) deeper. In fact, the MtG analogy is not surprising, given that Vaccarino is a veteran MtG player who pitched several design ideas to the MtG designers in the late 1990s.
After having played around 100 games, Dominion also reminds of Chess: it has traditional openings, annotated games, and a vocabulary very game-specific (e.g. greening or stalling). Dominion is a very deep game.
Of the 8 Dominion expansions, some have been received more favorably than others. For example, Alchemy is the third expansion. It adds potions, a new currency, and
not too many people enjoy playing just Alchemy games. On the other, the fourth expansion is called Prosperity, and it adds a lot of
over-the-top cards: compare, for example, Market from the basic game to Grand Market in Prosperity. This expansion is
certainly the most well-received.
The lesson here seems to be: make more awesome versions of what exists already, and adding extra currencies like Potions makes the game more complicated, but not necessarily more fun.
Dominion's unofficial ecosystem
A lot of unofficial projects emerged around Dominion. For example, a card set constructor helps you determine which cards to pick for your non-digital game(s) with friends. An AI simulator enables experts to polish their strategies by scripting basic AIs and running thousands of games between those AIs. The AI is provided from external files, and the returned graphs plot the average number of points earned per turn against the number of turns. As an example, this technique was used on the basic set of the first Dominion. There are also fan-made expansions, a zombie retheme, and a stand-alone program to play Dominion by yourself against AIs.
Since at least 2010, an online server called isotropic has been running Dominion games online. Its interface is very simple, and a lot of players have been enjoying the fact that it is free and of relatively good quality. Vaccarino has even been using it to playtest his expansions with select players. Along isotropic, there used to be councilroom, a website used to measure various statistics about Dominion cards from isotropic game logs. A lot of expert players seem to have enjoyed the stats reported by councilroom. And there used to be a free iPhone app that allowed people to play Dominion online with other people, but it was discontinued in April 2012.
Dominion generated dozens of projects run by motivated fans. How could a game publisher channel these fans? And how much control should be exerted?