Based on the elite squad-based Special Air Service (SAS) that had its beginning near the start of World War II, Hidden & Dangerous focuses on units designed to infiltrate enemy positions, carry out special assignments and conduct specialized operations. The units weren't all of a single purpose but were grouped by area of expertise, whether it was an interrogation unit, special boat force or some other requirement that needed special attention.
Gameplay revolves around six distinct campaigns, each divided into individual missions. Play is somewhat linear (with exceptions) in that most missions must be successfully completed before the next can begin and, correspondingly, all missions of a campaign must be completed before advancement to the next one can occur. Each mission can require a team of up to four commandos, chosen from an international field of 40 available, each with individual attributes, abilities and specialties.
Hidden & Dangerous contains a total of 23 missions with changeable weather patterns (rain, snow and fog), varying objectives and real-time movement through diverse terrain and locations. The game requires 3dfx graphics acceleration and provides viewpoint options from either first- or third-person perspectives. The world of Hidden & Dangerous is not stagnant, as objects within the environment move and react causing active strategic and tactical planning.
Up to four players can cooperate per team over a LAN or the Internet. The game comes with a wide-ranging arsenal of WWII equipment, weapons, vehicles and objects from communication devices to camouflage uniforms, explosives and sniper rifles. Hidden & Dangerous assigns and tracks a player's specific "profile" from the beginning of the game, updating and assigning scores for each mission, with the resultant ratings having an impact on future missions.