The Metal Slug storyline stretches from the beginning of the era of modern-day terrorism, set in the near-future of 2028. There are two militant factions that struggle for power: the Rebellion and the Regular Army. The Regular Army is a well-equipped, modern-day force run by various nations around the world. The Rebellion is comprised of various small, organized militant groups, ranging from terrorists to splinter groups of military forces driven by a hunger for power.
The Regular Army is a very formidable force. However, it lacks effectiveness due to the widespread corruption within the chain of command. Other officials often deny the reports and recommendations given to them by intelligence officers. This often leads to intelligence failures that result in dramatic consequences.
