|This article is written from the Real Life point of view|
There are two versions of Boss Alpha in Samus Returns.
The first version, known as Boss Battle 1 or Boss Alpha Mn, plays during encounters with standard Alpha Metroids on the Surface, Area 1, and Area 2. This theme is very tense, relying on dissonance to create a feeling of unease. Its instrumentation consists largely of synths and other electronic instruments with Game Boy-like beats. It can be heard here: 
The second version of Boss Alpha, aptly named Boss Alpha2, plays during encounters with Evolved Alpha Metroids starting in Area 2. This theme is much more aggressive and fast-paced with a more distinct melody, but shares its style and instrumentation with Boss Battle 1. This version can be heard here: 
The melody of Boss Alpha2 is notably similar to the original Metroid battle theme from Metroid II: Return of Samus, composed by Ryoji Yoshitomi. Both songs share a repeating four-note phrase, where the first two notes go down and the next two notes go up. While it lacks the opening stinger, Boss Alpha2 comes the closest to resembling the original theme when compared to other Metroid battle themes in the remake, which may have been Daisuke Matsuoka's way of incorporating the original theme.
- When Alpha Metroids are encountered in superheated rooms, neither version of this theme will play. Instead, a remix of the Lower Norfair theme continues to play during those battles. The same applies for Boss Gamma when Gamma Metroids are fought.
- Boss Alpha2 is heard in the Samus Returns Launch Trailer during a segment showing a Zeta Metroid Grab Sequence.