Marco and Tamra of the Peregrine Falcon Strike Force are back and tasked with wiping out General Morden's remaining. Four characters are playable with Eri and Fio of the Intelligence Ageny's S.P.A.R.R.O.W. squad also returning from Metal Slug 2. The action remains true to the series, featuring side-scrolling, fast-paced shooting and a variety of vehicles to control. New to the Metal Slug series are branching paths found within most levels. Although every path eventually leads to the same end level boss, the difficulty in getting there will vary as will the rewards.