Desert Rats is the second entry in R. T. Smith's World War II trilogy, including Arnhem and Vulcan. It simulates the North Africa Campaign in 1941-42 commencing with the arrival of Rommel in Tripoli and ends with the Battle of El Alamein. The bitter campaign includes Operations Battleaxe and Crusader and the Battle of Gazala. The game is named after the men of the 7th Armoured Division who were known as the Desert Rats after adopting a 'gerbil' as their insignia. Several versions like DOS and ZX Spectrum 128K includes two additional scenarios: Operation Compass and the Battle of Beda Fomm (December 1940-February 1941).

The gameplay is shown on a scrolling map by turns. Players select the units and give them orders to hold position, move to, fortify, or assault. Units move on the grid of rectangular cells. The balance of battles may be adjusted by Malta Status (Historical, Operation Hercules, Not used as base) as well. Historically, Montgomery defeated Rommel at El Alamein, and it is player's opportunity to alter the history making it sooner or vice versa.

The game is accompanied by a detailed instruction booklet including historical background notes of the campaign with maps and photographs. Two players representing Allied and Axis may be computer or human.