Complex sentence: The first issue of this name was digest size (5-1/2 "by 8-1/2") with just 32 pages, and dealt exclusively with Game Designers Workshop products with general military history regarding the subjects of those games.
Split into simpler sentences: The first issue in this guise was digest size (5-1/2 "by 8-1/2") with just 32 pages. The game dealt exclusively with Game Designers Workshop products, as well as general military history regarding the subject of those games.