|This article is written from the Real Life point of view|
|“||The fact that a piece of music containing only three notes has remained with everyone for so long is really surprising to me. I think it’s because that even before the music was in place, the game world of Metroid was fascinating.||„|
Title (Metroid) begins with a repeating six-note motif, a tense and mysterious high-pitched melody playing over low droning. It then transitions to a lighter section reminiscent of a lullaby, with high notes like the twinkling of stars. The song builds to a climactic series of arpeggios before resolving with the same low droning heard at the beginning. In the original game, it does not loop back to the beginning, instead repeatedly playing the low drone. It can be heard here: 
This song is one of several tracks that sound different between the NES and Famicom Disk System versions of Metroid, with the latter having higher-quality instrument samples. The FDS version is included in Super Metroid: Sound in Action, named Title (タイトル). The FDS version of the theme also appears in Nintendo Land, when selecting a mission from the Metroid Blast gate. It can be heard here: 
A synthesized arrangement by Tanaka is present on his Kid Icarus / Metroid Original Soundtrack Orchestra Version single, referred to as Title Music (タイトル音楽). It can be heard here: 
In Super Smash Bros. Melee, Title (Metroid) is partially remixed in Brinstar (Melee), a medley of songs from the original game. Here, the melody sounds very electronic, like the beeping of technology. Brinstar (Melee) is also featured in Super Smash Bros. Brawl and Super Smash Bros. for Nintendo 3DS and Wii U.
Smashing... Live!, a live orchestral performance of the Melee soundtrack, featured an arrangement of Brinstar Depths (Melee) and Brinstar (Melee) titled Depth of Brinstar. An orchestrated version of Title (Metroid) is heard during the Brinstar (Melee) segment, with low brass performing the droning and high woodwinds playing the melody.
Title (Metroid) is fully remixed in the original game's remake, Metroid: Zero Mission. This version moves the six-note motif to the end of the song, and then loops back to the beginning of the lighter section. An abridged version that only consists of the droning and six-note motif is heard in the Samus Data Screen and Options menu. Both versions are included in the Sound Test, the former as number 03 and the latter as 01. It can be heard here: 
Title (Metroid) was orchestrated as part of the Metroid medley in PLAY! A Video Game Symphony in 2011. This version sounds darker and more dramatic than usual, though still manages to sound heroic.
A remix of the full theme appears in Super Smash Bros. for Wii U on the Pyrosphere. Composed by Kohta Takahashi from Bandai Namco, this version incorporates part of Samus Aran's Appearance Fanfare at the beginning and the ending theme from Metroid at the end. This version of the song is included on the blue CD of the Smashing Soundtrack that was a Club Nintendo bonus for registering the Nintendo 3DS and Wii U games. It can be heard here: 
- The opening six notes of Title (Metroid) would be remixed in almost every Metroid game afterward, becoming a main theme for the series itself.