SR388 Underground

SR388 Underground is a theme from Metroid II: Return of Samus. It can be heard throughout Area 1, which features remnants and ruins of the Chozo civilization on SR388. The track is included on the Samus Archives Sound Selection CD that is included with the Special and Legacy Editions of Metroid: Samus Returns, a remake of Metroid II. Samus Returns features three remixes of SR388 Underground with the first being featured in Area 1 once again. Two even slower, more atmospheric versions can also be heard at the entrances to areas after the Chozo Seal of the previous area has been activated.

The original version can be heard here, the Samus Returns Area 1 version here, and the slower versions here and here.