Like a line of faceless soldiers on parade, military-combat games are tough to tell apart these days. ”FSW” has given the increasingly stale genre a fresh spin: Instead of assuming control of an individual soldier, you’re in the more passive role of a squad leader, moving two teams of infantrymen across urban settings full of ”tangoes” (soldier-speak for targets). And if the pacing seems deliberate — you give orders to fire but never actually shoot a gun yourself; squads spend a lot of time tiptoeing behind corners — the action is still very much in-your-face. Watching one of your GIs fall to a single bullet provides a harrowing exclamation point to ”FSW”’s immersive thrills.