Vicksburg was published in the October 1969 (Volume 2 Number 10) issue of International Wargamer, an IFW publication. It consisted of six pages of rules, three pages of OOB and playtest response form, two pages of counters (which needed to be colored, mounted, and cut out), and seven pages of maps (which needed to be cut out and assembled).
The rules seem typical for a simple wargame from this period, with a few embellishments such as rules for canal-building, mines, and mortars. The most unusual element of the game is that it takes place on two maps, a small map for campaign operations and a large map showing just the fortifications around Vicksburg. Units are presumably supposed to move between the two, but the rules are not entirely clear.