German games represent a throwback to older boardgames, like 3M's series of games or some of the better Parker Brothers classics of the past. They also represent a middle ground containing what is missing in many American game genres over the last 20 years or so: Games that are easy to teach to people of all ages, but also have enough strategy to interest adults.
German games don't require a large investment of time, money, or a deep interest in the subject like wargames, RPGs, miniatures and CCGs often do. You might pay $50 or more for a German game, but the game will be more or less complete and have nice components: wood or plastic pieces, nice artwork, etc. At the same price range in a wargame, you get cardboard counters. In RPGs, CCGs and minis, you are barely at the basic level of acquistion.
Of course, like potato chips, you can't get just one!
Ben Baldanza
The features common to most 'German-style' games that seem to attract all (including newcomers) are:
Interaction: You play the people as well as the game.
Interest: The designs keep you interested even when it's not your turn.
Consequence: Often moves early in the game have large consequences for your position later in the game.
Timing: Most can be played in 60-90 minutes, making tham a reasonable 'after dinner' type event.
Obviously with the wealth of games out there you can find exceptions to everything. But I think that these four characteristics are what set 'German-style' games apart from their party or puerile cousins in the U.S.
Joe Huber
German games are really those games meant to be sold to German families. Certainly there are many aimed at the most serious gamer, commonly referred to as a Spielfreak [or Spielfriek], but the bulk of the games produced are meant to be enjoyed by older children and adults alike. As such, they tend to have a few common characteristics:
Short length (rarely over ninety minutes, and sometimes as short as ten).
Fast play (many utilize simultaneous play, but even among those that do not "dead time" between turns is minimized).
An abstract game mechanism with a theme pasted over them.
Significant opportunities for strategy interlaced with carefully controlled luck elements.
Easily explained rules.
Appealing components (tokens, board, etc.).
The ability to handle three to five players.
Having grown up with wargames, Dungeons & Dragons, and the odd 3M game, I find that the theme tends to be important for me -- not what the theme is, so much, as how well the theme is tied to the mechanics. When the two don't match, I don't tend to enjoy the game as much -- even though when they do match it's far from being a simulation.
If you have any questions at all, about German-style games or anything else in the general realm of board games, please post a note in the About Board Games Forum. I check in almost every day, and there are lots of other regulars there who can help answer your questions as well. My experience has shown that game players are by and large quite sociable, willing to answer most questions now matter how simple -- so don't be shy!