Even your base of operations can be upgraded to provide additional bonuses in the field, such as a radar that highlights enemy positions, among others. (gamesradar.com)
Of course, the person playing had the advantage of intimate knowledge of the level, including enemy positions, which no doubt made it easier and faster to complete. (techtimes.com)
Each one — such as Zussman's ability to chuck you medkits and Pierson's trick of revealing enemy positions - appears depending on the mission you're in and can be regenerated by killing enemies. (techradar.com)