Weird -- while Nullsummenspiel is a literal translation of Zero Sum Game, the others have just taken one word from each title -- Feuer (Fire) for Seize the Fire, Bestien (Beasts) for Rough Beasts of Empire, and Zweitracht (Disharmony) for Paths of Disharmony.
Perhaps the literal Translations would have been too long to look good on the Cover:
Das Feuer ergreifen
Wilde Bestien des Imperiums
Pfade der Zwietracht
Especially the third sounds a bit strange in German, more like a Horror-B-Movie title. And of the course, lesser text means you can enjoy more of that beautiful background-picture.
Heh, I think the third is the only one that sounds appealing and the first two sound rather strange.