Fire on the Mountain concentrates on the action around Turner’s Gap and Fox Gap during Robert E. Lee’s first invasion of the North, emphasizing the difficulty of mountainous terrain and the seesaw nature of the battle into which reinforcements continue to trickle and the effects of mounting officer casualties. The game uses simple mechanics to simulate movement, artillery, cavalry, leaders, and difficult terrain, with a unique combat system that allows the game to move quickly while still simulating the tense nature of the battle.