|This article is written from the Real Life point of view|
Surface is considered to be the most memorable theme from Metroid II: Return of Samus, which was remixed in the reimagining of the game, Metroid: Samus Returns. It was originally composed by Ryoji Yoshitomi and later remixed by Daisuke Matsuoka.
In Return of Samus, Surface plays throughout Phase 1 and in most tunnels that are either currently or formerly flooded with purple liquid. As such, it is one of the most ubiquitous musical themes in the game, playing in every area except Phase 6 and Phase 9. While the rest of the game's soundtrack consists of dissonant, minimalist, or tense themes, Surface stands out for being one of the only upbeat and adventurous songs with a clear and distinct melody. It can be heard here: 
Samus Returns features three remixes of the original theme. The first is a slow, quiet, atmospheric version, titled M2 Surface Arr. In this version, the melody plays with high bells accompanied by low ambience. When Samus Aran first arrives on SR388, this theme plays throughout the Surface. Gradually, it is replaced with other themes, with the second remix taking over the southeast tunnels after the Scan Pulse is acquired, and Surface 2 taking over the planet surface's left half after the baby hatches. However, even in the endgame, this first remix can still be heard in the northeast tunnels if Samus backtracks there. It can be heard here: 
As previously mentioned, a second remix titled Surface 1 or Allarea A plays once the Scan Pulse Aeion Ability Artifact has been collected. It also plays throughout the Accolades Trailer. This one opens with deep choirs, similar to those heard in Chozo temples in Metroid Prime and Metroid: Zero Mission. Like the original theme, the melody here is exciting and energetic, performed by electronic synths. It can be heard here: 
- Moth Temple After Luminoth from Metroid Prime 2: Echoes has a very similar melody to Surface, although it is unknown if this was a deliberate reference.
- If the Scan Pulse is skipped in Metroid: Samus Returns, Surface 1 will never start to play.
- Surface 1's internal name, Allarea A, suggests that the theme may have once been intended to be played throughout SR388 in the remake, much like in the original game. Instead, M2 Ancient Chozo Ruins Arr and Matad Ambi fulfill its original role as the music played in purple liquid tunnels. Additionally, the internal name of Chozo Laboratory is Allarea B; it is unknown how the two themes might have been connected.