After my presentation on Eurogames, one conference attendee told me that he was still confused. "What, exactly, makes a Eurogame different from any other game?"
I cited a number of different qualities, all of which taken together would lead to calling a game a Eurogame. This didn't satisfy him; he was looking for something concrete insofar as classification.
As he walked away, I immediately realized that Eurogames are not a class of games - such as race games and capture games - but a period of games, or an art movement.
There exists in the world today a game design movement called Eurogame design. Its roots run back to the 1960s, it began flourishing in the 1980s, and it spread worldwide in the 1990s.
A particular game might be from one branch of the Eurogame period. A particular game might straddle several design movements: Eurogame, war game, trivia game, and so on, taking elements of each to create a specific game meant to target those who enjoy one or more of these movements. We call games that seem to incorporate about 50% of their design each from two different movements "hybrid games", but many games fall in between movements, more or less.
You can see the working of game design periods/movements throughout the twentieth century and into this one. Morality games followed one after another in earlier centuries. After Monopoly, we saw not only clones of Monopoly games with different themes but different economic games with similar goals and mechanics. Hundreds of trivia games followed Trivial Pursuit. And, on a smaller scale, dozens of worker placement games have followed Caylus. Video games follow the same pattern.
Crassly speaking, we may look at later games as simple attempts to capitalize and monetize on the success of the previous game. This may be true in the vast majority of cases. On the other hand, like books, paintings, and movies, we can expect that at least some of the followup games see something interesting about the original game and incorporate the new mechanics, like new technology, in an attempt to explore a newly discovered territory opened by the original.
(We can see art movements within games themes, as well as mechanics. There was a sizable market for multiple morality games. Likewise, there is room in the hobby games market for multiple games about Renaissance Italy or WWII. I expect, though I have not looked, that games about certain themes come in waves, just as do games with certain mechanics.)
Considering the movements or periods of game mechanics, games are similar to any designed object: cups or chairs or cars. They seem different because we use and interact with games for a longer period and for different reasons. But how we look at these other objects in design terms should guide how we look at games.