Metal Slug Attack contains different unique soundtracks heard only in the game, however in Another Story mode, each faction had its own unique battle theme. The latter is heard from the first 3 stages while the 4th and last stage has its own theme.

'Scrap Island' is the main battle theme of the Regular Army in Another Story, while originally it is first heard in Metal Slug 7/XX's first mission.

'Be Headquartered in the City' is the main battle theme of the Rebel Army in Another Story. While it is first heard in the Queen's Battle Extra Ops however it is one of Metal Slug 3D's main OST.

The Ptolemaic Army's battle theme in Another Story is a rearrangement or remix of Run Through, which is the main theme of Metal Slug 5's mission 4 (first half).

While the Alien faction doesn't remix or reuse soundtracks from previous Metal Slug games, it does have its own unique battle theme. A seemingly futuristic, xenon, and techno-themed soundtrack.

Like the Alien faction, the Independent faction has its own unique theme. A yet melodic, adventure-themed battle theme which is unique compared to most of the game's OST which is such called as 'Fated Destiny'.